> *The Future Directions in Ultraviolet Spectroscopy conference is
> sponsored by the Astrophysics Division of the National Aeronautics and
> Space Administration's Science Mission Directorate, (NASA HQ) and the
> Canadian Space Agency (CSA). Additional support has been provided by
> the French Space Agency, Centre National d\'Etudes Spatiales (CNES).*

**Future Directions in Ultraviolet Spectroscopy**

October 20-22, 2008

Annapolis, Maryland

Final Program

October 15, 2008

**Sunday, October 19, 2008**

17:00 -- 19:00 Registration and Opening Reception

**Monday, October 20, 2008**

Session I, Chair and Provocateur: B. Savage

9:00 C. Danforth (I) Finding \"Missing\" Baryons in the Local Universe?

9:30 T. Tripp (I) New Results on O VI Absorbers, Warm-Hot Intergalactic
Gas, and

Feedback

10:00 A. Narayanan (C) Probing the WHIM Gas Through Ne VIII Absorption

10:15 Discussion

10:30 -- 11:00 Coffee Break and Poster Viewing

Session II, Chair and Provocateur: C. Howk

11:00 R. Lallement (I) Local Interstellar Medium: New Perspectives

11:30 D. Bowen (I) The Distribution of Hot Gas in the Disk of the Milky
Way

12:00 V. Dixon (C) FUSE Observations of O VI Emission from the Milky Way

and Beyond

12:15 Discussion

12:30 -- 13:30 Lunch and Poster Viewing

Session III, Chair and Provocateur: T. Heckman

13:30 A. Aloisi (I) A UV Perspective of Starburst Galaxies

14:00 G. Kriss (I) FUSE Observations of Active Galactic Nuclei and
Prospects for the

Future

14:30 N. Lehner (C) The Magellanic System - Accretion, Feedback

14:45 Discussion

15:00 -- 15:30 Coffee Break and Poster Viewing

Session IV, Chair and Provocateur: A. Fullerton

15:30 R. Prinja (I) Mass Loss from Hot Stars

16:00 K. Werner (I) Abundances in Hot Evolved Stars

16:30 N. Walborn (C) Systematics of Magellanic Cloud OB Spectra from
FUSE

16:45 Discussion

Invited talks (I) -- 30 minutes, including discussion

Contributed talks (C) -- 15 minutes, including discussion

**Tuesday, October 21, 2008**

Session V, Chair and Provocateur: C. Froning

9:00 K. Long (C) Disks, Winds, and White Dwarfs in Cataclysmic Variables

9:15 S. Engle (C) The Secret FUV/X-ray Lives of Cepheids

9:30 K. France (C) Far-UV Studies of H2 Emission from Photodissociation
Regions

9:45 V. Lebouteiller (C) Metal enrichment in the neutral gas of blue
compact dwarfs

10:00 S. Mathur (C) Super-solar metallicity in AGNs measured with FUSE

10:15 Discussion

10:40 -- 11:15 Coffee Break and Poster Viewing

Session VI, Chair and Provocateur: J. Linsky

11:15 C. Oliveira (I) D/H Observations: Present Understanding and Future
Perspectives

11:45 G. Steigman (I) Tracking The Post-BBN Evolution Of Deuterium

12:15 Discussion

12:30 -- 13:30 Lunch and Poster Viewing

Session VII, Chair and Provocateur: C. Grady

13:30 E. Guinan (I) The Sun in Time: Effects of the Young Sun\'s
Radiation

14:00 A. Brown (I) The Ultraviolet Environment of Protoplanetary Systems

14:30 A. Gomex de Castro (C) The formation of planetary disks and winds

14:45 -- 15:15 Coffee Break and Poster Viewing

15:15 A. Vidal-Madjar (I) Ultraviolet Studies of Extra-Solar Planets

15:45 A. Roberge (I) Gas in Protoplanetary and Debris Disks

16:15 C. Martin-Zaidi (C) H~2~ in the circumstellar environments of
Herbig Ae/Be stars

16:30 Discussion

18:00 - 20:00 Conference Dinner (included with registration)

> W. Oegerle (I) After Dinner Remarks
>
> Director Astrophysics Division NASA GSFC

**Wednesday, October 22, 2008**

Session VIII, Chair and Provocateur: J. Morse

9:00 M. Shull (I) The Cosmic Origins Spectrograph and the Future of UV
Astronomy

9:30 C. Martin (I) The Galaxy Evolution Explorer: Results and Future
Implications

10:00 S. McCandliss (C) Essential observations of the Lyman continuum

10:15 -- 10:45 Coffee Break and Poster Viewing

10:45 K. Werner (C) WSO/UV - Ultraviolet mission for the next decade

11:00 J. Green (I) Future Ultraviolet Observatories

11:30 M. Postman (I) Future of UV Astronomy

12:00 Discussion

12:30 Lunch

14:00 End of Conference

Oral Presentations & Discussions

Monday, October 20, 2008

**Session I, The Nearby Inter-Galactic Medium**

Dr. Blair D Savage University Wisconsin, Madison

savage@astro.wisc.edu

**Finding \"Missing\" Baryons in the Local Universe?**

Dr. Charles W Danforth University of Colorado

danforth@casa.colorado.edu

Simulations predict that shocks from large scale structure formation and
galactic winds have reduced fraction of baryons in the warm,
photoionized phase (the Lya Forest) from nearly 100% in the early
universe to less than 50% today. Some of the remaining baryons are
predicted to lie in the warm-hot ionized medium (WHIM) phase at
T=105-107 K, but the quantity remains a highly tunable parameter of the
models. Modern UV spectrographs we have allowed us unprecedented access
to both the Lya Forest and potential WHIM tracers in the local universe.
Several independant groups have constructed large catalogs far-UV
absorbers along multiple AGN sight lines. There is general agreement
between the surveys that the warm, photoionized phase makes up 30% of
the baryon budget at z\~0. Another 10% can be accounted for in collapsed
structures. However, interpretation of the \~100 high-ion (OVI, etc)
absorbers at z\<0.4 is more controversial. These species are readily
created in the shocks expected to exist in the IGM but they can also be
created via photoionization and thus not represent WHIM material.

I review here the results from several large IGM surveys and discuss the
evidence for photoionized vs. WHIM OVI. Given the observational evidence
and theoretical expectations, I argue that most of the observed OVI
absorbers represent shocked gas at T\~105.5 rather than photoionized gas
and are thus valid tracers of the WHIM phase. Given this assumption,
enriched gas at T=105-6 can account for \~10% of the baryon budget at
z=0. The remaining 50% of the \"missing\" baryons may reside in gas
T\>106 or in metal-poor regions. Finally, I discuss ways in which COS
data can expand the legacy of FUSE and STIS to solve the photo/shock OVI
debate and account for additional WHIM baryons.

**A High-Resolution Survey of Low-Redshift QSO Absorption Lines: New
Results on O VI Absorbers, Warm-Hot Intergalactic Gas, and Feedback**

Dr. Todd M Tripp University of Massachusetts

tripp@fcrao1.astro.umass.edu

Currently, two broad questions are driving observational and theoretical
studies of the low-redshift intergalactic medium: (1) Are the missing
baryons located in the \"warm-hot\" intergalactic medium (WHIM) at the
present epoch? Hydrodynamic cosmological simulations predict that as the
universe evolves and large-scale structures grow, intergalactic gas
accretes into increasingly deeper potential wells, and a substantial
amount of intergalactic material is shock heated. By z = 0, the
simulations predict that 20 - 50% of the baryons are shock heated to
temperatures of 1e5 - 1e7 K, the so-called WHIM. This is purported to be
a robust prediction from these popular simulations, but is there any
observational evidence of the WHIM? (2) How do galaxies affect their
surroundings, and how do surroundings affect their galaxies? Processes
grouped under the rubric of \"feedback\" (e.g., supernova- or AGN-driven
outflows) are often invoked to solve problems in galaxy evolution, but
observational constraints on feedback are still quite limited.
Conversely, theorists have suggested that gas accretion is more complex
than previously thought and occurs in \"cold\" and \"hot\" flavors.

To provide observational constraints relevant to these topics, we have
been conducting a high-resolution spectroscopic study of the
low-redshift IGM using QSO absorption lines. This talk will summarize
several new results from this survey, with a focus on QSO absorption
systems detected in the O VI doublet. The O VI doublet is frequently
detected in low-z QSO spectra, but it will be shown that the absorbers
have some surprising properties, e.g., the gas is often cooler than
expected (T \<\< 1.0e5 K), sometimes quite enriched with metals (in some
cases approaching solar metallicity), and rather far from luminous
galaxies.

**Probing the WHIM Gas Through Ne VIII Absorption**

Dr. Anand Narayanan University of Wisconsin

Bart P. Wakker, Blair D. Savage

anand@astro.wisc.edu

We report the detection of Ne VIII in the intergalactic medium at
z=0.32566 in the FUSE spectrum of the z=0.6460 quasar 3C263. The Ne VIII
770 feature is detected at a significance of 2.9 sigma. This is a
conservative limit since the measurement also takes into account the
continuum placement and fixed pattern noise errors. Additionally, O III,
O IV and N IV are detected at the same velocity as Ne VIII. The
rest-frame equivalent width of the Ne VIII 770 feature is Wr=50.7+/-17.5
mA, with an apparent column density of log N(Ne VIII)=14.02(-0.18 +0.13)
and b(Ne) = 67.3+/-4.1 km/s. The Ne VIII 780 line is heavily
contaminated by Ly-gamma at z =0.089. The rest-frame equivalent widths
of the other lines are Wr(O III 832)=96.5 ± 14.1 mA, Wr(O IV
788)=79.8+/-12.9 mA and Wr(N IV 765)=87.9+/-18.8 mA. The low ionization
O II 834 line is not detected, with a 3 sigma upper limit of 21 mA.

Using photoionization models, we show that the Ne VIII traces gas of a
different density and temperature compared to the moderately ionized
species. A single phase model of photoionized gas within a column
density range of log N(HI)=14.6-16.2 cm-2, log n\~-3.83 cm-3, and a
metallicity range of \[Z/H\]=0.09 to -1.78, can explain the observed O
II, O III, O IV and N IV. However, for this range of metallicity, the
models require a log n\~-6 cm-3 in order to reproduce the observed N(Ne
VIII). Alternatively, collisional ionization in a hot gas can also
generate the observed N(NeVIII). This would require temperatures in
excess of 105 K, making this system an interesting probe of the
shock-heated warm-hot intergalactic medium (WHIM). COS observations will
provide better constrains on the physical nature of this multiphase
system through coverage of associated O VI and H I lines.

**Session II, The Interstellar Medium**

Dr. Chris Howk Univesity of Notre Dame

jhowk@nd.edu

**Local Interstellar Medium: New Perspectives**

Dr. Rosine Lallement Service d\'Aéronomie /IPSL/UVSQ

Rosine.Lallement@aerov.jussieu.fr

I will discuss some recent results on the local interstellar gas
distribution : -titanium absorption measurements and updated
correlations between deuterium and metals. -dense gas distribution
inferred from optical absorption data. -recent modeling of X-ray
emission following charge exchange between solar wind high ions and
interstellar neutrals, induced contamination of the soft-X ray
background and consequences for the Local Cavity hot gas. -comparison of
X-ray data with high ions from FUSE (Welsh et al): both suggest a lack
of hot gas at small distance of the galactic plane in the local cavity.
I will discuss the need for new high resolution soft X-ray, UV and
optical data.

**The Distribution of Hot Gas in the Disk of the Milky Way**

Dr. David V Bowen Princeton University

E. B. Jenkins, T. M. Tripp, K. R. Sembach, B. D. Savage, H. W. Moos

dvb@astro.princeton.edu

We review the results of a FUSE-team program designed to characterize
the distribution of hot gas in the disk of the Milky Way. By observing
OVI absorption lines towards 148 early-type stars at distances of more
than 1 kpc, combining our new results with earlier surveys of OVI, and
eliminating stars that show conspicuous localized X-ray emission, we
find an average OVI mid-plane density of 1.3e-8 cm-3. The density
decreases away from the plane of the Galaxy in a way that is consistent
with an exponential scale height of 3.2 kpc at negative latitudes or 4.6
kpc at positive latitudes. Average volume densities of OVI along
different sight lines exhibit a dispersion of about 0.26 dex,
irrespective of the distances to the target stars. This indicates that
OVI does not arise in randomly situated clouds of a fixed size and
density, but instead is distributed in regions that have a very broad
range of column densities, with the more strongly absorbing clouds
having a lower space density. Line widths and centroid velocities are
much larger than those expected from differential Galactic rotation, but
they are nevertheless correlated with distance and OVI column density,
which reinforces our picture of a diverse population of hot plasma
regions that are ubiquitous over the entire Galactic disk. The velocity
extremes of the OVI profiles show a loose correlation with those of very
strong lines of less ionized species, supporting a picture of a
turbulent, multiphase medium churned by shock-heated gas from multiple
supernova explosions.

**FUSE Observations of O VI Emission from the Milky Way and Beyond**

Dr. W. Van Dyke Dixon Johns Hopkins University

R. Sankrit (USRA)

wvd@pha.jhu.edu

Observers using the Far Ultraviolet Spectroscopic Explorer (FUSE) have
detected emission in the 1032 and 1038 A resonance lines of the
lithium-like O VI ion from a variety of sources in the Milky Way and
Magellanic Clouds, including planetary nebulae, supernova remnants,
superbubbles, and the diffuse interstellar medium. Observed line
intensities span three orders of magnitude, from a few thousand line
units (photons/s/cm2/sr) for the faintest interstellar sight lines (a
limit set by the detection threshold of FUSE) to a few million line
units for the brightest supernova remnants. In this talk, we review
these results, highlighting some unexpected discoveries \-- such as the
detection of collisionally-excited O VI in several planetary nebulae and
of photoionized O VI around a hot white dwarf \-- and pointing out some
general conclusions about O VI emission that run contrary to our initial
expectations. We discuss the scientific questions that could be
addressed by a next-generation survey of O VI emission.

This work is supported by NASA grant NAS5-32985 to the Johns Hopkins
University.

**Session III, Galaxies and Active Galactic Nuclei**

Dr. Tim Heckman Johns Hopkins University

heckman@pha.jhu.edu

**A UV Perspective of Starburst Galaxies**

Dr. Alessandra Aloisi Space Telescope Science Institute

aloisi@stsci.edu

Starbursts are an important component of both the low- and high-redshift
Universe. Thanks to their proximity, local starbursts constitute a
perfect laboratory where to test our ideas about star formation,
evolution of massive stars, physics and chemical evolution of the ISM.
This type of studies is also fundamental in order to better understand
star-formation phenomena in more distant galaxies, the connection
between the low- and high-z universe and the processes involved in the
origin and evolution of galaxies, including mergin, accretion and
feedback. The rest-frame UV spectral range provides unique insights into
the starburst phenomenon by offering unique diagnostic tools for
investigating the properties of the hot massive stars and the different
ISM phases. I will review several key results from past UV observations
of nearby starburst galaxies, including FUSE observations, and I will
give an overview of the open issues that can only be addressed by the
next generation of UV observatories.

**FUSE Observations of Active Galactic Nuclei and Prospects for the
Future**

Dr. Gerard Kriss Space Telescope Science Institute

gak@stsci.edu

Over its 8-year lifetime, the Far Ultraviolet Spectroscopic Explorer
observed over 200 hundred active galactic nuclei (AGN). Many of these
observations were campaigns dedicated to AGN science, including
coordinated observations with other observatories such as Chandra,
XMM-Newton, and the Hubble Space Telescope. However, most observations
were part of large samples of nearby AGN that served as background
probes of gas in the interstellar medium, the Galactic halo and the
local intergalactic medium. These large samples and the dedicated
campaigns have broadly advanced our understanding of the far-ultraviolet
continuum of AGN and the ubiquitous outflows of photoionized gas from
their active nuclei. The bright, nearby, lower-luminosity AGN observed
with FUSE generally have bluer continua than their higher luminosity
counterparts observed with HST, and the spectral shapes are broadly
consistent with accretion disk models. More than half of the Type 1 AGN
observed with FUSE show blueshifted intrinsic absorption by the O VI
doublet, indicative of highly ionized outflows from the central nuclear
regions. I will give an overview of these observations, and interpret
them in the context of winds from accretion disks and thermally driven
winds originating from the obscuring torus, with an eye toward what
observational capabilities are needed in the future to understand the
role of outflows in the structure and evolution of AGN, and their impact
on their environments.

**The Magellanic System - Accretion, Feedback: What have we learnt from
FUSE?**

Prof. Nicolas Lehner University of Notre Dame

nlehner@nd.edu

Characterizing the infall and outflow of gas and metals in galaxies is
crucial for understanding the evolution of galaxies and the
intergalactic medium. The study of these phenomena in local galaxies
provides the most robust diagnostic tests for models of tidal
interaction, galactic winds, and accretion of primordial material onto
galaxies, which are important for piecing together the history of matter
and metals in the Universe. The Magellanic System with its high-velocity
complexes connected to the Magellanic Clouds provides a laboratory where
the techniques of gas-phase absorption line spectroscopy can be used to
study the gas toward many individual stars and QSOs. Many of the FUV
spectra show significant blueshifted and redshifted interstellar
absorption relative to the systemic velocities of the SMC and LMC,
signatures of outflow and infall in these galaxies. FUSE provides the
largest and highest quality LMC/SMC database in the FUV and has truly
open the door to new sciences and discoveries in these galaxies. I
discuss how present (and future) observations in the UV bandwith have
changed our view of these nearby galaxies and what can we learn from it
for the higher redshift Universe.

**Session IV, Hot Massive Stars**

Dr. Alex W. Fullerton Space Telescope Science Institute

fullerton@stsci.edu

**Mass Loss from Hot Stars**

Prof. Raman K Prinja University College London

rkp@star.ucl.ac.uk

This review deals with some of the key areas where FUSE spectroscopy
advanced our understanding of hot star winds. The power of the far-UV
spectral line diagnostics observed by FUSE is discussed in the context
of both time-averaged and temporally varying winds. The results
encompass diverse, but related settings, including the winds of luminous
OB stars, disk-driven outflows from cataclysmic variable binaries, and
the fast winds of PN central stars.

The current serious discordance of different mass-loss estimates for
O-type stars is described, and the pivotal role played by analyses of
FUSE observations of the PV resonance line doublet is highlighted.
Because this discordance has wide ranging implications, its confirmation
and resolution are extremely important. Currently, the origin of the
problem is thought to be clumping (or, more generally structure) in
winds, which is not well characterized by the current theories used to
interpret the observations. However, before progress can be made, the
nature of the clumping must be constrained. I discuss how additional
FUSE diagnostics, together with a multi-wavelength strategy may provide
the needed information.

FUSE time-series data have also provided unique insights into the
structured and variable outflows in other hot star systems. Successes
include the first detections of migrating DAC-like features in the fast
winds of PN central stars, and new perspectives on global modulation,
often strictly periodic, in the collimated outflows from the inner
accretion disks of cataclysmic variable binary stars.

**Abundances in Hot Evolved Stars**

Klaus Werner University of Tuebingen, Germany

T. Rauch, J.W Kruk

werner@astro.uni-tuebingen.de

We present results of abundance analyses in hot (pre-) white dwarfs and
central stars of planetary nebulae. We concentrate on hydrogen-deficient
objects, for which the results allow to conclude on interior
nucleosynthesis and mixing processes in the progenitor AGB stars. The
analyses are almost entirely based on ultraviolet spectroscopy performed
with HST and primarily with FUSE. We identify observational and modeling
requirements that are necessary to achieve further progress in this
field.

**Systematics of Magellanic Cloud OB Spectra from FUSE**

Dr. Nolan R Walborn Space Telescope Science Institute

Eliceth Rojas, Alex W. Fullerton

walborn@stsci.edu

The FUSE data for 287 OB stars in the Magellanic Clouds are an
unprecedented resource to investigate the behavior of the stellar winds
as a function of spectral type, luminosity class, and metallicity. The
smaller extinction and interstellar absorption relative to Galactic
counterparts render the MC sample more powerful, especially below 1100
A. IUE provided a comparable Galactic sample at longer UV wavelengths,
but HST has yet to do the same in the MCs. An initial FUSE atlas of 47
objects published in 2002 charted several basic trends, including the
luminosity (or wind-density) sensitivity of the S IV, P V, and C III
profiles, analogous to the previously unique Si IV behavior at longer UV
wavelengths; this effect is due to the relatively low ionization of
these species except for P V, for which the much lower abundance
prevents saturation at lower luminosities. Now we are augmenting our
sample by about 150 more objects, to provide better coverage of the
parameters and redundancy at some spectral types, as well as to
investigate categories of peculiar objects. Some outstanding early
results are increased representation of the earliest spectral types
(O2-O4), and the extension of the CNO dichotomy between O2 and ON2
spectra to the superionized O VI profiles. This work and subsequent
quantitative modeling will improve our understanding of stellar winds,
massive stellar evolution, and the integrated spectra of distant
starbursts.

Oral Presentations & Discussions

Tuesday, October 21, 2008

**Session V, Scientific Breadth of UV Spectroscopy**

Dr. Cynthia S. Froning CASA, University of Colorado

cfroning@origins.colorado.edu

**Far Ultraviolet Observations of Disks, Winds, and White Dwarfs in
Cataclysmic Variables**

Knox S Long Space Telescope Science Institute

long@stsci.edu

Cataclysmic variables are the nearest and most easily studied
laboratories for understanding accretion onto compact objects. FUSE has
provided the first significant sample of high resolution, high S/N
spectra of such objects in the wavelength range 900-1183 A. As expected,
the FUSE spectra of most nova-like variables and dwarf novae in outburst
show broad features associated with emission from the inner accretion
disk. Detailed modeling has proven difficult, however, because the flux
near the Lyman limit is higher than expected, indicating that the
vertical structure of the disk differs significantly from that of normal
stellar atmospheres of similar temperature and gravity. Wind features,
due to OVI and CIII, are also evident in many systems, and in most cases
are accompanied by fairly narrow lower ionization-state lines that are
blue shifted by no more than a few 100 km/s. These narrower features and
the small number of systems with P-Cygni-like profiles suggest that most
of the wind features observed with FUSE arise in material fairly near
the disk surface, a picture quite different from that inferred from
analyses of longer wavelength HST data. Dwarf nova systems in optical
quiescence show FUV emission from the WD, which is heated by and cools
after outbursts, and from the disk, and, surprisingly, at least in some
cases, the hot spot. Here I will briefly illustrate the observational
contributions FUSE has made to our understanding of cataclysmic
variables, describe the quantitative state of the modeling, and suggest
where we might go from here.

**The Secret XUV Lives of Cepheids: FUV/X-ray observations of Polaris
and beta Dor**

Scott G Engle Villanova University

Edward Guinan and Nancy Evans

scott.engle@villanova.edu

We report on the surprising recent discovery of strong FUV emissions in
two bright, nearby Classical Cepheids from analyses of FUSE archival
observations (combined with one of our own approved observations just
prior to the failure of the satellite). Polaris and beta Dor are
currently the only two Cepheids to have been observed with FUSE, and
beta Dor is the only one to have multiple spectra. Both Cepheids show
strong C III (977Å, 1176Å) and O VI (1032Å, 1038Å) emissions, indicative
of 50,000 - 500,000 K plasma, well above the photospheric temperatures
of the stars. Also, more remarkably, beta Dor displays variability in
the FUV emission strengths which appears to be correlated to its 9.84-d
pulsation period. This phenomenon has never before been observed in
Cepheids. The FUV studies are presented along with our recent
Chandra/XMM X-ray observations of Polaris and beta Dor, in which X-ray
detections were found for both stars. Further X-ray observations have
been proposed to unambiguously determine the origin and nature of the
observed high energy emissions from the targets, possibly arising from
warm winds, shocks, or pulsationally induced magnetic activity. The
initial results of this study are discussed, along with their impact on
understanding the structure, heating, dynamics and possible magnetic
activity of Cepheid (and related Hybrid Star) atmospheres. We gratefully
acknowledge support for this project from NASA grants:
Chandra-GO6-7011A, XMM-Newton grant NNX08AX37G, FUSE grant 06-FUSE8-0088
and NSF grant AST05-07542.

**Far-UV Studies of H2 Emission from Photodissociation Regions**

Dr. Kevin France University of Colorado

Stephan R. McCandliss (Johns Hopkins University)

kevinf@colorado.edu

Photodissiocation regions (PDRs) lie at the interface between a strong
ultraviolet radiation field and a dense molecular cloud, often the cloud
associated with the formation of a hot star. PDRs cover the transition
from HII region (traced by ionized gas) to molecular cloud (traced by
molecular emission from species like CO). A thin boundary layer exists
between these phases, where the ultraviolet spectrum of PDRs is
dominated by fluorescent H2 emission and dust scattered stellar
continuum. These regions are difficult to isolate because they require
clouds in close proximity to an OB star and a favorable geometry with
respect to earth. We present a mini-survey of five local PDRs carried
out with FUSE. We use these data to characterize the far-UV spectra of
PDRs for the first time and to refine models of the H2 fluorescent
emission process. We find that our models can adequately reproduce the
observed emission spectra of three of these regions (IC 63, M42, and IC
405). The remaining two (NGC 2023 and NGC 7023) do not show clear
emission from H2 in the FUSE band, despite the well defined and
characteristic double-peaked emission features at 1575 and 1608 A
observed in these object, as well as the clear fluorescent signatures in
the well studied near-IR rovibrational emission lines, thus suggesting a
more complex radiative transfer scenario in these environments.

**Metal enrichment in the neutral gas of blue compact dwarfs: the
compelling case of Pox 36**

Dr. Vianney Lebouteiller Cornell University

D. Kunth, T. X. Thuan

vianney@isc.astro.cornell.edu

The presence of extremely metal-poor dwarf galaxies in the Local
Universe is a challenge for models of galaxy chemical evolution. Within
the chemical downsizing scenario, it is expected that dwarf galaxies can
remain quiescent for times longer than the Hubble time. Such galaxies
are thus ideal targets to seek for pristine gas in the present day
Universe. Chemical abundances in the ionized gas of HII regions within
star-forming dwarf galaxies such as IZw18 lead to the conclusion that
there could be a minimum metallicity due to a single starburst episode.
This naturally explains the difficulty to find metal-poor objects while
emphasizing the need for observing other gaseous phases. The search for
pristine gas has since pursued with the study of the neutral envelope
around galaxies. Such gas could have remained partly unprocessed since
the galaxy formation, except via mixing of material ejected at
high-galactic latitude by supernovae (SNe) events. We will present
results obtained with the FUSE telescope indicating that the neutral gas
of the blue compact dwarf galaxy Pox 36 has already been enriched with
heavy elements. Furthermore, the ionized gas of the HII regions is found
to be \~10 times more metal-rich. We argue this can be explained by
successive localized star-formation episodes, with 99% of the SNe
products mixing in the HI phase (increasing only slightly its
metallicity) and only 1% mixing locally. Pox 36 and other galaxies are
compared to draw a general picture in which the neutral gas of BCDs
systematically harbor a metallicity deficiency.

**Super-solar metallicity in AGNs measured with FUSE**

Prof. Smita Mathur The Ohio State University

Dale Fields et al.

smita@astronomy.ohio-state.edu

Measuring metallicity in the nuclear regions of AGNs is difficult
because only a few lines are observed and ionization correction becomes
a major problem. Nitrogen to carbon ratio has been widely used as an
indicator for metallicity, but precise metallicity measurements have
been lacking. We made such measurements for the first time using a wide
baseline of ionization states with observations from FUSE, HST and
Chandra. OVI observations with FUSE were crucial in this effort. We
measured super-solar metallicities in two AGNs and found that N/C does
not scale with metallicity. This suggests that chemical enrichment
scenario in nuclear regions of AGNs may be different from traditional
models of galactic metal enrichment, at least in the high metallicity
regime.

**Session VI, Deuterium**

Prof Jeffrey L Linsky JILA/University of Colorado and NIST

jlinsky@jila.colorado.edu

**D/H: Present Understanding and Future Perpectives, An Observers Point
of View**

Dr. Cristina M Oliveira The Johns Hopkins University

H. Warren Moos

oliveira@jhu.edu

Determining the abundance of deuterium in the Galaxy was one of the
primary goals of the FUSE mission. FUSE-based D/H and D/O measurements
have been published for about thirty new lines of sight, probing column
densities and distances that had not been previously accessible. The
measurements confirmed that the deuterium abundance is variable on
relatively small spatial scales. This had been observed before by
Copernicus and IMAPS, albeit for a small number of sightlines. Together
with previous D/H measurements, the FUSE observations led to a model
that explains the D/H variations in terms of variable depletion of
deuterium onto dust grains. Although not perfect and probably not the
complete final answer this model is a big step forward in trying to
understand the abundance of deuterium in the Milky Way. Such a model
would not have been possible without the backdrop of the many FUSE
measurements.

In this talk we review all the Galactic measurements of D/H and discuss
the causes of uncertainty in these measurements and how they can be
affected by systematic errors. We consider the possible causes of the
D/H variability and explore future scientific directions that will allow
us to better understand the behavior of D/H in the Galaxy.

**Tracking The Post-BBN Evolution Of Deuterium**

Dr. Gary Steigman Ohio State University

steigman@pacific.mps.ohio-state.edu

The primordial abundance of deuterium produced during Big Bang
Nucleosynthesis (BBN) depends sensitively on the universal abundance of
baryons (the baryon to photon ratio). Observations of deuterium in
high-redshift, low-metallicity QSO Absorption Line Systems (QSOALS)
provide a key baryometer, determining the baryon abundance at the time
of BBN to a precision of \~5%. In the post-BBN universe, as gas is
cycled through stars, deuterium is only destroyed so that the abundance
measured anytime, anywhere, bounds the primordial abundance from below.
A comparison of the deuterium abundances inferred from observations of
enriched, processed material in the Galaxy with the primordial abundance
offers a constraint on models of Galactic chemical evolution. In this
talk the BBN-predicted deuterium abundance will be compared with the
primordial value inferred from QSOALS, testing the standard cosmological
model. The relic abundance is further compared with the FUSE-inferred
deuterium abundances in the local ISM constraining models of post-BBN
Galactic chemical evolution.

**Session VII, Protoplanetary Systems**

Dr. Carol A Grady Eureka Scientific and GSFC

Carol.A.Grady@nasa.gov

**The Sun in Time: Effects of the Young Sun\'s Strong X-ray-FUV
Radiation on Terrestrial Planets & Life**

Prof. Edward F Guinan Villanova University

Scott G. Engle, Laurence DeWarf

edward.guinan@villanova.edu

Multi-wavelength studies of solar analogs (G0-G5 V stars) with ages from
\~50 Myr to 9 Gyr have been carried out as part of our \"Sun in Time\"
program. These studies infer that the young Sun was rotating over 10x
faster than today and as a consequence, these young solar-type stars,
and the young Sun, had vigorous magnetic dynamos and correspondingly
strong coronal X-ray and transition region/chromospheric FUV-UV
emissions up to several hundred times stronger than the present Sun. The
chief science goals are (1) to study the solar magnetic dynamo (with
rotation as the only variable) and (2) to determine the radiative and
magnetic properties of the young Sun with the purpose of constructing
spectral irradiances that are being used to study paleo-planetary
atmospheres. The strong radiation and particle fluxes inferred for the
young Sun have major implications and impacts on the photochemistry and
photo-ionization of paleo-planetary atmospheres (in particular for the
terrestrial planets) and also play important roles in the possible
atmospheric erosion of the planets as well as studying their suitability
for life. Recent results of the effects of the young, active Sun\'s
enhanced X-ray/FUV emissions and wind fluxes on the early Earth (as well
as on Venus and Mars) will be discussed. The importance of planetary
magnetic fields in protecting the young planets\' atmospheres from the
erosive effects of young Sun\'s strong X-UV and plasma fluxes also will
be briefly discussed. The important role played by FUSE FUV
spectrophotometry of solar-type stars will be emphasized. We are
grateful for the support from grants from NASA (FUSE, XMM, Chandra and
HST)and from NSF/RUI grants. We also express our thanks to the FUSE team
for their heroic efforts in extending the FUSE mission

**The Ultraviolet Environment of Protoplanetary Systems**

Dr. Alexander Brown CASA, University of Colorado

Alexander.Brown@colorado.edu

Young stars undergoing the conversion of pre-main-sequence circumstellar
disks into protoplanetary systems are strong sources of high energy
(FUV/EUV/X-ray) radiation that controls the physical and chemical
processes in their circumstellar environment out to hundreds of AU from
the star. The high energy emission, both as radiation and particles,
resulting from magnetic activity on the central star controls the
thermal structure of disks, the formation process of planetesimals, and
the photoexcitation, photoionization, and photodissociation of atoms and
molecules forming protoplanets and in young planetary atmospheres.
Modeling of the dust and gas evolution requires an accurate
understanding of the local radiation field throughout the UV and X-ray
spectral regions, even those parts of the spectrum that are impossible
to observe from Earth. Most young stars are well over 100 pc from the
Sun and are consequently hard to observe in the UV at even moderate
spectral resolution. Fortunately, members of the \`\`Local
Association\'\' \[offshots from the ongoing Sco-Cen star-formation
complex\], whose ages range from 7 Myr to a few hundred Myr, surround
the Sun at distances of 50 pc or less and permit the detailed study of
the early evolution of stellar activity. I shall review the current
knowledge of the level and range of UV and X-ray stellar activity within
the various Moving Groups of the Local Association, describe a few
well-studied examples in detail, and discuss how future observations
could improve our understanding of the role of the stellar radiation in
shaping the protoplanetary environment.

**The formation of planetary disks and winds: an UV view**

Prof. Ana I Gomez de Castro Universidad Complutense de Madrid

aig@mat.ucm.es

Planetary systems are angular momentum reservoirs generated during star
formation. This accretion process produces very powerful engines able to
drive the optical jets and the molecular outflows. A fraction of the
engine energy is released into heating thus the temperature of the
engine ranges from the 3000K of the inner disk material to the 10MK in
the areas where magnetic reconnection occurs. There are important
unsolved problems concerning the nature of the engine, its evolution and
the impact of the engine in the chemical evolution of the inner disk. Of
special relevance is the understanding of the shear layer between the
stellar photosphere and the disk; this layer controls a significant
fraction of the magnetic field building up and the subsequent
dissipative processes ought to be studied in the UV.

This contribution focus on describing the connections between 1 Myr old
suns and the Sun and the requirements for new UV instrumentation to
address their evolution during this period. Two types of observations
are shown to be needed: monitoring programs and high resolution imaging
down to, at least, milliarsecond scales.

**Ultraviolet Studies of Extra-Solar Planets**

Dr. Alfred Vidal-Madjar IAP-CNRS-UPMC

alfred@iap.fr

Transmission spectroscopy is a powerful tool for probing atmospheres of
extra-solar planets when transiting their parent star. The first
detection of an atmospheric species was NaI in HD209458b (Osiris),
thanks to the Hubble Space Telescope (HST) sensitivity reaching \~10-4
in relative absorption depth. Still with HST, HI, OI and CII were
discovered in the far UV, and more recently in the UV, H_2 via Rayleigh
scattering. This underlines once more the potentialities of the UV-farUV
spectral domain where a large number of diagnostic lines are available.

The next steps will be the detection and characterization of additional
species toward further extra-solar planets, hopefully down to Earth-like
worlds which will require sensitivities in the \~10-6 range.
Fortunately, wide absorption bands of particular interest do exist in
this spectral domain. Key parameters for their detection are the parent
star spectral type, the density of the planet and the thickness of the
atmosphere. From model simulations one can estimate the number of
potential targets for a future UV space mission as a function of its
collecting area.

**Gas in Protoplanetary and Debris Disks: Insights from UV
Spectroscopy**

Dr. Aki Roberge NASA Goddard Space Flight Center

Aki.Roberge@nasa.gov

Over the last two decades, observations of protoplanetary and debris
disks have played an important role in the new field of extrasolar
planetary studies. Many are familiar with the extensive work on the cold
circumstellar dust present in these disks done using infrared and
sub-millimeter photometry and spectroscopy. However, UV spectroscopy has
made some unique contributions by probing the elusive but vital gas
component in protoplanetary and debris disks. In this talk, I will
outline our picture of the evolution of protoplanetary disks and discuss
the importance of the gas component. New insights obtained from UV
spectroscopy will highlighted, as well as some new puzzles. Finally, I
will touch on upcoming studies of gas in protoplanetary and debris
disks, some at UV wavelengths, some at far-IR and sub-mm wavelengths.

**Molecular hydrogen in the circumstellar environments of Herbig Ae/Be
stars probed by FUSE**

Dr. Claire Martin-Zaidi Laboratoire d\'Astrophysique de Grenoble

Deleuil, Le Bourlot, Bouret, Roberge, Dullemond, Testi, Feldman,
Lecavelier des Etangs, Vidal-Madjar

claire.martin-zaidi@obs.ujf-grenoble.fr

H2 gas is the most abundant molecule in the circumstellar (CS)
environments of young stars. It is a key element in our understanding of
the evolution of pre-main sequence stars and their environments towards
the main sequence. At the present time, little is known about the gas as
compared to the dust in the environments of young stars. We thus
observed H2 around a sample of pre-main sequence stars in order to
better characterize their CS environments. We analyzed the FUSE spectra
of \~20 Herbig Ae/Be stars (HAeBes) covering a broad spectral range. To
better diagnose the origin of the detected H2 and its excitation
conditions, we used a model photodissociation region (PDR). Our analysis
demonstrates that the excitation of H2 is clearly different around most
of the HAeBes compared to the interstellar medium. Moreover, the
characteristics of H2 around these stars give evidence for different
excitation mechanisms. For the most massive Be stars, the excitation
diagrams are reproduced well by a PDR model. Our results favor an
interpretation in terms of large CS envelopes, remnants of the molecular
clouds in which the stars were formed. On the other hand, the group of
Ae stars known to possess disks is more inhomogeneous. In most cases,
when CS H2 is detected, the lines of sight do not pass through the
disks. The excitation conditions of H2 around Ae stars cannot be
reproduced by PDR models and correspond to warm and/or hot excited media
very close to the stars. Our results suggest structural differences
between Herbig Ae and Be star environments. Herbig Be stars do evolve
faster than Ae stars, and consequently, most Herbig Be stars are younger
than Ae ones at the time we observe them. It is thus more likely to find
remnants of their parent cloud around them.

Oral Presentations & Discussions

Wednesday, October 22, 2008

**Session VIII, The Future of UV Astronomy**

Dr. Jon A Morse NASA

jon.morse@nasa.gov

**The Cosmic Origins Spectrograph and the Future of UV Astronomy**

Dr. Michael Shull University of Colorado

michael.shull@colorado.edu

After the fall 2008 servicing mission, the Hubble Space Telescope should
again provide exciting discoveries, through UV spectroscopic studies of
quasars, galaxies, clusters, hot stars, white dwarfs, planetary objects,
and the large reservoirs of gas between the stars, in galactic halos,
and throughout the intergalactic medium. The next 5-10 years should be
promising for UV science on Hubble, with the new COS and restored STIS
spectrographs on a 2.4-meter telescope. However, both UV and X-ray
astronomy are falling behind, compared to the advances made at other
wavebands, both in aperture and through investments in new
instrumentation. During the upcoming NRC Decadal Study, the US
space-astronomy community should consider whether it can afford to
abandon high-energy (UV/X) windows on many astrophysical objects and
phenomena in the universe. Will we be able to support (and afford)
future transformative missions with large aperture and high throughput,
such as ATLAST (UV/O) and IXO (X-ray)? Or is the future likely to be
with moderate-size missions?

**The Galaxy Evolution Explorer: Results and Future Implications**

Prof. Christopher Martin California Institute of Technology

GALEX Science Team

cmartin@srl.caltech.edu

The Galaxy Evolution Explorer (GALEX) continues to map the ultraviolet
sky.

GALEX surveys have supported the following galaxy evolution
investigations: calibrating UV as a star formation rate tracer, using
wide and deep surveys to measure star formation history, studying the
evolution of dust extinction and metallicity, selecting and analyzing
galaxies in transitory states, finding local analogs to Lyman Break
Galaxies, probing and time-dating star formation in a wide variety of
physical regimes, and probing star formation properties in low mass, low
density settings. Our continuing mission is focussed on relating star
formation history and galaxy evolution paths to the properties of dark
matter halos and their assembly history, and on beginning to relate the
evolution of galaxies to that of black holes and the intergalactic
medium. Over and above GALEX\'s study of galaxy evolution the surveys
are: finding all UV bright QSOs at low and high redshift, discovering
tidal capture flares from inactive black holes, discovering shock
breakout flashes from distant supernovae, selecting a sample of galaxies
for Baryon Acoustic Oscillation surveys, and in our own Milky Way,
discovering and diagnosing spectacular new stellar wind nebulae from
aging, mass-losing stars. In this talk I will review some of these
results and surprising discoveries, and describe how UV missions in the
future (small to large), motivated in part by, and expanding upon the
results of GALEX, could play a key role in the next decades.

**Essential observations of the Lyman continuum**

Dr. Stephan R McCandliss Johns Hopkins University

stephan@pha.jhu.edu

Concurrent observations of Lyman continuum (LyC) and Lyman alpha (LyA)
emission escaping from star-forming systems at low redshift are
essential to understanding the physics of reionization at high redshift
(z \>\~ 6). Some have suggested reionization is dominated by numerous
small galaxies with LyC escape fractions f_e \~ 10%, while others
suggest quasars with higher f_e might also play a role. At z \> 3,
direct observation of LyC leakage becomes progressively more improbable
due to the increase of intervening Ly limit systems, leaving LyA as the
primary diagnostic available to the James Webb Space Telescope for
exploring the epoch of reionization. If a quantitative relationship
between escaping LyC and LyA emission can be established at low z, then
the diagnostic power of LyA as a LyC proxy at high z can be fully
realized. Here I review past and ongoing efforts to detect the elusive
LyC and present detection requirements for future efforts as a function
of redshift and escape fraction. At redshifts 0.02 \< z \<\~ 1.3 modest
aperture instruments (\~ 1 m) with large grasp can determine whether low
mass galaxies have higher f_e than high mass galaxies, as has been
suggested to be the case at high redshift. Such an instrument can also
provide concurrent LyA information and perhaps even begin to trace the
seeds of the cosmic web. At 1.3 \< z \< 2.9, observations of LyC become
zodiacal background limited and consequently will require much larger
spacebased telescopes. Such a large telescope should be capable of
revealing the cosmic web of LyA in its full glory.

**WSO/UV - Ultraviolet mission for the next decade**

Klaus Werner University of Tuebingen, Germany

B. Shustov, M. Sachkov, A.I. Gomez de Castro, M. Huang, N. Kappelmann,
I. Pagano

werner@astro.uni-tuebingen.de

The World Space Observatory UltraViolet (WSO/UV) is an international
space mission led by Russia and devoted to UV spectroscopy and imaging.
The observatory includes a 170cm aperture telescope capable of UV
spectroscopy and deep UV and optical imaging. The project is included in
the Federal Space Program of Russia for the period 2006-2015. Launch is
planned for the mid of the next decade.

The instrument suite consists of i) a high-resolution (R=55,000) double
echelle spectrograph for the wavelength range 102-320nm, ii) a
low-resolution (R=2000) long-slit spectrograph covering the same
wavelength range, and iii) a number of UV/optical imaging cameras having
different resolution and field-of-view.

**Future Ultraviolet Observatories**

Dr. James C Green University of Colorado

james.green@colorado.edu

I will review the fundamental science drivers for future
optical/ultraviolet observatories, as well as the future infrastructure
capabilities to support them. I will also discuss some conceptual
mission concepts for observatory class as well as medium and small class
observatories and discuss the strengths and weaknesses of the various
approaches.

**The Future of UV Astronomy**

Dr. Marc Postman Space Telescope Science Institute

Matt Mountain

postman@stsci.edu

Major astrophysics facilities in the 2020 decade and beyond will be
addressing scientific problems that cannot be addressed by the
capabilities of ANY of today\'s current or planned missions. Identifying
the fundamental questions that will NOT be answerable in the coming
decade is the challenge facing those who are beginning to envision the
observational capabilities that will be required of large space-based
missions of the future. I will, with great humility, attempt to frame
some of the key scientific, technological, and programmatic leaps
astronomers will need to make if we are to have a vibrant space-based
program in the next 20 years.

Contributed Posters

Monday, Tuesday, and Wednesday,

October 20, 21, 22, 2008

**Transient Processes in the Atmosphere of Alpha Tau**

Dr. Vladimir Airapetian George Mason University at NASA/GSFC

K. G. Carpenter(GSFC), T. Ake (CSC/JHU)

vladimir.airapetian@nasa.gov

The Far Ultraviolet Spectrograph Explorer (FUSE) spectra of UV emission
lines observed in Alpha Tau (K5 III) at two epochs separated by four
months show dramatic differences in emission line fluxes and line
shifts. This presents the first evidence of dynamic plasma heating in
the active region of this cool giant star. We discuss these observations
in terms of Alfven wave heating in magnetic loops.

**The Impact of Accurate Distances on UV Spectroscopy of White Dwarfs
and Cataclysmic Variables**

Paul Barrett US Naval Observatory

Patrick Godon

barrett.paul@usno.navy.mil

J-MAPS and GAIA are two astrometry missions to be launched in 2011. The
positions and parallaxes of stars brighter than 15 magnitude will be
measured to an accuracy of 1000 and 25 microarcseconds, giving distances
to better than 1 parsec. Accurate distances allow us to constrain the
luminosity and hence temperature, radius and mass of isolated white
dwarfs. With a sufficiently large sample, evolutionary models can be
tested. For white dwarfs in binaries where the mass is known, the
atmospheric structure can be extrapolated to zero temperature to test
the mass-radius relation. For cataclysmic variables, evolutionary models
can also be tested, particularly for dwarf novae in quiescence where the
white dwarf is detected. By measuring the temperature of the white
dwarf, the long term accretion rate of the binary can be estimated and
compared with the expected accretion rate of magnetic braking for CVs
above the period gap (\>3 hr) and gravitational braking for those below
the gap (\< hr). For nova-like systems, whose luminosity is dominated by
the accretion disk and affected by interstellar extinction and
reddening, accurate distances can help constrain the temperature profile
of the disk. With a sufficient sample, standard disk models can be
tested.

**The fundamental parameters of massive stars**

Dr. Luciana Bianchi Johns Hopkins University

James Herald (JHU), Miriam Garcia (IAC, Spain)

bianchi@pha.jhu.edu

We analyzed far-UV (FUSE), UV (HST, IUE) and optical spectra of hot
massive stars in the Milky Way with non-LTE, line-blanketed models with
expanding winds. We were able to reconcile previously discrepant
diagnostics from H alpha to the highly ionized far-UV lines (e.g. OVI,
NV) with a revised treatment of X-rays from shocks and clumping in the
stellar wind. These effects could be fully constrained thanks to the
lines in the FUSE range. A revised (downwards) Teff scale has resulted,
and previous discrepancies in the estimate of mass loss rate from
optical and UV lines have been reconciled.

**The UV sky surveys: a road-map for future UV missions**

Dr. Luciana Bianchi Johns Hopkins University

et al.

bianchi@pha.jhu.edu

Unprecedented UV surveys of the sky in two UV bands, FUV and NUV, and
catalogs of UV sources, are provided by the Galaxy Evolution Explorer
(GALEX). We describe the major surveys, which have different depth and
coverage, and we characterize the nature of the UV sources. The UV
surveys, linked to a multi-wavelength archive, offer great sensitivity
to detect and characterize several classes of astrophysical objects,
including low-redshift QSOs, white dwarfs in the Milky Way, and
star-forming galaxies.

**FUSE Observations of O VI Absorption in the Large Magellanic Cloud**

Dr. William P Blair Johns Hopkins University

C. M. Oliveira, S. M. LaMassa, and C. W. Danforth

wpb@pha.jhu.edu

We have embarked on a project to characterize the global properties of O
VI absorption toward stars in the Large Magellanic Cloud observed with
FUSE. Earlier studies with a smaller sample of stars established that O
VI absorption is ubiquitous and spatially variable. However, at least
one study has claimed that localized enhancements in O VI column density
may be associated with nebular sub-structures such as superbubbles
(SBs). It is the aim of our program to perform a broader analysis of O
VI absorption characteristics using all of the data available.

O VI ISM absorption in LMC stellar spectra shows a wide range of
appearances, depending on the stellar spectral type and luminosity class
as well as the presence or absence of galactic or intermediate velocity
absorption. Hence, we have performed a spectral morphology
classification of the sight lines. We have also identified sight lines
with little or no LMC ISM O VI. Without including such sight lines, the
dispersion of LMC O VI absorption (attributed to the halo of the LMC)
has been underestimated, and the average value has been overestimated.
We are using these data to assess whether excess O VI absorption can be
attributed to nebular sub-structures within the LMC such as superbubbles
(SBs) or supershells. We will discuss this and other aspects of the
project and report our preliminary findings.

This project has been funded through a NASA FUSE Cycle 5 Legacy grant
NNG05GE03G to The Johns Hopkins University.

**The FUSE/MAST Magellanic Clouds Legacy Project**

Dr. William P Blair Johns Hopkins University

C. Oliveira, S. LaMassa, S. Gutman, C. Danforth, A. Fullerton, R.
Sankrit, R. Gruendl, K. Levay

wpb@pha.jhu.edu

We present a new online resource through the High Level Science Products
program at the Multi-Mission Archive at Space Telescope (MAST) involving
reprocessed data for all FUSE stellar sight lines in the Magellanic
Clouds. We have reprocessed the entire FUSE sight line database of stars
observed in both Magellanic Clouds (187 in the LMC, 100 in the SMC)
using the final version of the FUSE calibration pipeline, CalFUSE 3.2.
Where multiple data sets were available, they have been combined to
improve data quality. We provide subsets of these data in several
formats, along with 20 arcmin FOV optical and infrared context images
for each sight line. The data formats include a set of spectral postage
stamps of interstellar absorption lines aligned in heliocentric
velocity, an enlargement of the spectral region near the important O VI
doublet lines, and an overview spectrum of the entire FUSE spectral
range for each object. The imagery includes MCELS optical H alpha, \[S
II\], and \[O III\] emission line images and infrared 3.6, 8, and 24
micron data from Spitzer. These context images are available as three
color composites in each band and as individual images in black and
white. The availability of these diverse data sets in a convenient
online interface provides a significant quick look capability that will
allow researchers to effectively utilize this rich archival FUSE data
set for a wide variety of science investigations. The web site for the
FUSE/MAST Magellanic Clouds Legacy Project is
http://archive.stsci.edu/prepds/fuse_mc/ This project has been funded
through a NASA FUSE Cycle 5 Legacy grant NNG05GE03G to The Johns Hopkins
University.

**A multiwavelength study of the close environment of HD34078**

Dr. Patrick Boissé Institut d\'Astrophysique de Paris

Boissé, Rollinde, Hébrard, Hily-Blant, Pety, Federman, Sheffer,
Andersson, Marmin, Pineau, Roueff

boisse@iap.fr

To clarify the origin of highly excited H2 detected with FUSE toward
HD34078 (Boissé et al. 2005), we mapped the CO(2-1) emission at
12-arcsec resolution in the field. The data show a pronounced maximum
near HD34078\'s position, indicating that the star and diffuse cloud are
closely associated. The comparison of one MDRS and seven LWRS FUSE
spectra of HD34078 shows that LWRS spectra are significantly
contaminated by diffuse emission. No variations of N(H2, J=0) are
detected among the LWRS spectra, over four years. The analysis of the
high S/N MDRS spectrum allows the detection of H2 absorption up to the
v=3, J=1 level and yields improved estimates for all N(H2,v,J) values. A
series of new visible CH and CH+ absorption lines have been obtained
between 2003 and 2008. Our measurements confirm the reality of rapid,
large amplitude and correlated variations of N(CH) and N(CH+) previously
detected by Rollinde et al. (2003). Temporal variations in CH and CH+
line profiles are also clearly seen. The available observations suggest
a picture in which HD34078\'s wind swept up ambient molecular gas to
form a dense shell of gas and dust, coincident with the bow shock seen
by France et al. (2007). The amount of highly excited H2 is well
consistent with the shell-star distance. Further, the large CH and CH+
abundances and time variations can be understood as a result of a high
CH+ production rate due to a shock and/or the presence of an
inhomogeneous turbulent mixing layer at the cloud/wind interface. To the
contrary, gas located well beyond the interface should be little
affected by the presence of the star and the lack of significant N(H2,
J=0) variations indicates the absence of marked density structure in the
ambient cloud over scales of about 10 - 100 AU.

**Abundance Patterns in Hot Subdwarf B Stars: The Case of Carbon**

Dr. Pierre Chayer STScI

G. Fontaine, F. Wesemael, J. Dupuis, J.W. Kruk, and E.M. Green

chayer@stsci.edu

Hot subdwarf B stars (sdB) are helium core burning stars without a
hydrogen burning layer. They have effective temperatures ranging from
22,000 K to 40,000 K and gravities ranging from log g = 5.0 to 6.2.
After the helium core exhaustion, sdB stars evolve to low mass white
dwarfs without reaching the asymptotic giant branch. One of the most
puzzling phenomena observed at the surface of sdB stars is their
abundance anomaly. For instance, high-resolution optical spectroscopy
shows that the carbon abundance is lower than the solar abundance by
about a factor of ten on average. A few stars, however, show a solar
abundance or an abundance higher than solar. Although optical
spectroscopy allows the measurement of relatively high carbon abundance,
it fails to measure stringent upper limits when no carbon lines are
detected. The Far Ultraviolet Spectroscopic Explorer (FUSE) comes to the
rescue when no carbon lines are detected in the optical, because it is
1,000 times more sensitive than the VLT for the purpose of measuring
very small amounts of carbon in the atmospheres of sdB stars. We measure
the carbon abundance in the FUSE spectra of 31 stars. We confirm the
carbon abundance trend reported in previous studies, but report the
disappearance of carbon in five stars. The upper limits that we measure
for these stars are about four orders of magnitude lower than the solar
abundance. The observation of very low carbon abundance suggests that
the normal equilibrium between gravitation and radiative levitation has
been disrupted, perhaps by a weak stellar wind.

**Gas Content in the Debris Disks of Nearby A-type Stars**

Prof Kwang-Ping Cheng California State University Fullerton

James E. Neff (College of Charleston)

kcheng@fullerton.edu

Since the IRAS discovery of Vega\'s large thermal infrared excess over
the expected photospheric flux, dust disks have been found around a
large fraction of main-sequence A-type stars. While dust in debris disks
has been studied extensively with Spitzer, relatively little is known
about their gas content. We have carried out detailed studies of the
circumstellar environments of all nearby A-type stars. We have studied
both thermal emission from their circumstellar dust and absorption from
circumstellar gas. With high-resolution and high signal-to-noise visible
spectra, we identified about a dozen main-sequence A-type stars with
circumstellar gas through a volume-limited survey. Although these
spectra confirm the existence of the circumstellar gas and serve as a
probe of the gas dynamics, they do not allow us to determine the gas
density and temperature. Fortunately, there are many absorption lines in
the UV and FUV range that are sensitive to the gas density and
temperature. Through our FUSE, IUE, HST, and ground-based observations,
we found five of these stars with variable, infalling circumstellar gas
similar to that seen in spectra of Beta Pic. This unique set of stars
allows us to study the evolution of both gas and dust in the
circumstellar disks of A-type stars at the same time. We will describe
what we have been able to learn from the subset of these stars observed
with before the termination of the FUSE mission. Our FUSE results
regarding the evolution of gas in debris disks raise further questions
that can only be answered with future high-resolution UV spectroscopy
missions.

**Far-UV Constraints on Mass Outflows in Active Galactic Nuclei**

Dr. Michael Crenshaw Georgia State University

Steven B. Kraemer

crenshaw@chara.gsu.edu

Mass outflows from Active Galactic Nuclei (AGN) are revealed through
high-ionization absorption lines in the UV that are blue shifted with
respect to their host galaxies. The mass outflow rates are comparable to
the accretion rates needed to power the active supermassive black holes,
indicating the importance of outflows in determining the overall
structure and energetics of AGN. Using high-resolution UV spectroscopy
from FUSE and HST, including multiple-epoch observations of the variable
absorption lines, we have derived detailed constraints on the physical
conditions, transverse velocities, and locations of the outflowing
absorbers. We have also recently isolated a component of the emission
lines that likely arises in the outflowing absorbers, which allows us to
place tight constraints on the locations, geometry, and dynamics of the
outflows. In the best-studied Seyfert galaxies to date, NGC 4151, the
available evidence favors magnetocentrifugal winds over radiation
driving or thermal expansion as the dominant acceleration mechanism for
the outflows.

**Intergalactic HI and Metal Absorbers at z\<0.4**

Dr. Charles W Danforth University of Colorado

J. Michael Shull

danforth@casa.colorado.edu

We present results from a large survey of the low-redshift IGM using
STIS and FUSE observations toward 28 AGN. Our survey includes 640 HI
absorption systems (Lyman lines) at z\<0.4 and corresponding absorbers
in seven metal ions (OVI, CIII, CIV, SiIII, SiIV, NV, and FeIII). In a
redshift path length of 5.27, we detect the largest sample of metal
absorbers to date in the low-z IGM: 83 OVI systems, 39 CIII, 53 SiIII,
24 CIV, 24 NV, etc. We determine completeness-corrected column density
distributions, statistical metallicities, and more accurate estimates of
the IGM baryon content for all species. In the low-z IGM, we have
accounted for \~40% of the baryons: 30% in the photoionized Lya forest
and up to 10% in the 105-106 K warm-hot intergalactic medium (WHIM) as
traced by OVI. Improved statistics for weak OVI absorbers allows us to
estimate Omega_WHIM/Omega_b=8.6+-0.8% down to log(N_OVI)=13.0. The NV
absorption follows a similar pattern to OVI, with both ions providing
reliable tracers of the portion of the WHIM at T=105-106 K. However, CIV
is not as clearly a WHIM tracer, and it may be present in both
collisional and photoionized phases. The ions CIII, SiIII, and SiIV are
well correlated with HI and show patterns typical of photoionization.
Adjacent ion stages of the same element (CIII/IV and SiIII/IV) provide
useful constraints on the photoionization parameter, log(U)=-1.5+-0.2.
Observed OVI and NV detections require an ionization field \~10 times
stronger, supporting our hypothesis that these ions trace the WHIM
phase. Comparison of SiIV and CIV with high-z surveys shows a modest
increase in line density, consistent with increasing IGM metallicity at
recent epochs. Even at z\<0.4, there is some evidence for evolution
among IGM absorbers.

**CalFUSE and the Final FUSE Archive**

Dr. W. Van Dyke Dixon Johns Hopkins University

J. W. Kruk (JHU)

wvd@pha.jhu.edu

In support of the final data archive of the Far Ultraviolet
Spectroscopic Explorer, we have reprocessed the entire FUSE data set
using CalFUSE v3.2, the latest version of the FUSE data-reduction
software. Recent improvements to CalFUSE include effective-area and
background files for the final two years of the mission; software
modifications to increase the signal-to-noise ratio of observation-level
spectral files for histogram data; software modifications to extract
spectra from airglow exposures and to produce quick-look spectral plots
for the airglow exposures associated with each observation; and database
changes to standardize the assignment of object classes for observations
of the background sky and bright Earth. Future CalFUSE users will
benefit from modifications that allow the pipeline to be compiled on
additional fortran compilers (f77, f90, g77, gfortran) and operating
systems (Solaris 10, Linux, Mac OS X), including machines with 64-bit
architectures. Finally, we have conducted an assessment of the archival
data quality, including analyses of the remaining systematic
uncertainties in the effective-area and wavelength calibrations.

This work is supported by NASA contract NAS5-32985 to the Johns Hopkins
University.

**Intrinsic Ultraviolet Absorbers in Active Galactic Nuclei**

Dr. Jay P Dunn Virginia Tech

D. Michael Crenshaw, N. Arav, S. B. Kraemer, M. Bautista

jdunn77@vt.edu

We present Far Ultraviolet Spectroscopic Explorer (FUSE) measurements
and photoionization analysis of UV absorption in the 3 observations of
the low-z Seyfert 1 object IRAS F22456-5125. These 5 distinct, narrow
(FWHM \> 200 km/s) absorbers span a significant range in velocity (\~ 0
to -700 km/s) and ionization (Lyman series, C III, N III, and O VI). We
find that the object shows little evidence for corresponding X-ray
absorption, and shows variability in the continuum flux of the object
(by a factor of 6) and variability within one of the 5 components in the
timescale covered by the FUSE observations, component 4. This provides
us with an upper limit on the distance of 602 pc for component 4.

In the coming HST cycle we will observe this object and 5 other low-z
quasars and Seyfert galaxies with the Cosmic Origins Spectrograph (COS)
as part of a systematic effort to determine the chemical abundances of
AGN. Three of these objects show strong C III absorption, which leads us
to believe that these targets are good candidates to search for C III\*
1173 A. This will provide us with both the density and the distance to
the absorbers for several objects, which therefore yield the kinetic
luminosity for the outflows. These measurements will be instrumental in
determining the relationship between absorbers in Seyfert galaxies and
higher luminosity quasars where we are currently finding distances and
densities for several objects in the latter category.

**Far Ultraviolet Spectroscopy of Hot DA White Dwarfs: a retrospective
and looking forward**

Dr. Jean Dupuis Canadian Space Agency

Pierre Chayer, Stephane Vennes, Vincent Henault-Brunet, and Jeffrey W.
Kruk

jean.dupuis@space.gc.ca

With its unprecedented sensitivity and spectral resolution, FUSE has
been sources of important data that have helped further our knowledge
and understanding of white dwarf stars. We will summarize the results
based on our search for heavy elements in white dwarf atmospheres since
the last FUSE conference and present an interpretation of the observed
abundance patterns and their implications on diffusion theory. In the
spirit of this conference, we will discuss the current limitations to
our understanding of abundance patterns in white dwarfs, and address the
scientific requirements for a future far ultraviolet spectroscopic
mission specific to the study of degenerate stars.

**Symbiotic binaries: testbeds for mass-loss, accretion physics, and
atomic data**

Dr. Brian R Espey Trinity College Dublin

Cian Crowley, Stephen McCandliss, Gary Ferland

brian.espey@tcd.ie

Symbiotic binaries are the widest separation interacting systems,
consisting of a red giant primary and (generally) a white dwarf
secondary. The strong spectral distinction between cool and hot star -
and also their interaction region - gives rise to a range of separable
emission and absorption features from both collisional and photoionised
material.

For those symbiotic systems which undergo eclipses, we can obtain
further (unique) information on stellar mass loss by observing the
spectrum of the white dwarf as it passes behind the extended atmosphere
of the giant primary. In this instance, time-resolved spectra enable us
to derive tomographic information to directly determine the physics of
mass-loss (e.g., abundances, temperature, ionisation), at least in the
plane of the system. The main goal of our work in the UV and far-UV has
been to utilise these systems to derive self-consistent models for mass
loss -- including the velocity field -- from the giant surface out to
the circumbinary material.

A portion of the wind from the giant flows towards the secondary, and
this material can sometimes be diagnosed in absorption. We have found
evidence for partial coverage of the white dwarf with clumpy material,
with short (orbit-to-orbit) variations in appearance from inflow to
outflow. For systems that outburst due to material accreted onto the
white dwarf, the far-UV allows insight into the progress of the eruption
and processed material properties. We have observed the ejection of a
narrow shell of material from one such system, that subsequently
dissipates, as the spectrum of the system recovers towards its
pre-outburst state.

I shall also comment on the use of symbiotic binary spectra as testbeds
for atomic data.

**Connections between low-z and high-z O VI observations**

Dr. Andrew J Fox European Southern Observatory

afox@eso.org

Of all the absorption lines in the far-UV, none has gained as much
attention from FUSE as the OVI doublet. In this talk I will present
observations of OVI absorption at z\>2 using high-resolution
ground-based spectroscopy, in various classes of absorption-line system,
including the IGM and gamma-ray-burst host galaxies. Comparisons will be
made between the properties of the high-redshift and low-redshift O VI
populations. The goal will be to demonstrate how space-based UV studies
of O VI and other high ions at low redshift provide valuable context for
understanding the high-redshift Universe, and are crucial to understand
the evolution of cosmic structure from high-redshift to the present day.

**Far-UV Studies of H2 Emission from Photodissociation Regions**

Dr. Kevin France University of Colorado

Stephan R. McCandliss (Johns Hopkins University)

kevinf@colorado.edu

Moved to Session V, Scientific Breadth of UV Spectroscopy as a
Contributed Talk 10/21/2008 9:30:00 AM

**A Survey of Milky Way Dust Extinction in the FUSE Far-Ultraviolet**

Karl D Gordon STScI

Cartledge, S., & Clayton, G.

kgordon@stsci.edu

New results on the Milky Way interstellar extinction in the
far-ultraviolet will be presented. Far-ultraviolet (912-1150 A)
extinction curves for 80+ sightlines have been constructed using
targeted and archival FUSE spectra. The important effects of H_2
absorption are modeled and removed prior to constructing the extinction
curves. The extinction curves were constructed using the standard pair
method. The standard stars used were carefully dereddened using
comparisons to the existing dereddened IUE standard stars and requiring
a smooth progression in spectra with spectral type. All the sightlines
probed have existing mid-ultraviolet (from IUE or STIS) extinction
curves allowing for a direct comparison of the mid- and far-ultraviolet
extinctions. This large set of FUSE extinction curves provides a
detailed probe the extinction due to small dust grains. Comparisons to
CCM curves and FM fits will be presented as well as limits on residual
extinction structures.

**The Nearest Herbig Ae Star Transitional Disks**

Dr. Carol A Grady Eureka Scientific and GSFC

J. Wisniewski, B. Woodgate, M. Kuchner, G.M. Williger, K.A. Collins

Carol.A.Grady@nasa.gov

As a result of more than 20 years of infrared astronomy from space,
circumstellardisks can be most easily identified from excess light over
that expected to be produced by the photosphere of the star. The shape
of this IR spectral energy distribution (SED) has been used to infer the
accretion rate onto the star and the degree of dust grain growth and
settling in protoplanetary disks. More recently, it has been used to
identify disks with warm dust deficits, the \"transitional\" disks.
Flared disks are expected to be gas-rich, and concentrated among the
younger systems lacking evidence of grain growth and settling, and in
those with higher current accretion rates. However, transitional disks
with dust deficits in the inner disk have similar SEDS to flared disks.
By combining FUSE FUV excess light measurements, the SED data, disk
outer radius measures, and the radial surface brightness of the disk in
scattered light, we test the hypothesis that the majority of Herbig Ae
star disks detected in scattered light have flared disks. Instead, we
find that the majority of these disks are flatter structures. Low
current accretion rates sampled by FUSE FUV spectra further suggest that
these disks are the nearest intermediate-mass transitional disks. We
next use the presence or absence of accretion onto the star to identify
those transitional disks which are likely to harbor planetary mass
companions.

**Living with a Red Dwarf: FUV & X-ray emissions of dM stars and effects
on hosted Planets**

Dr. Edward F Guinan Villanova University

Scott G. Engle and Trisha Mizusawa

edward.guinan@villanova.edu

Red Dwarf (dM) stars are overwhelmingly the most numerous stars in our
Galaxy. These cool, faint and low mass stars make up \> 80% of all
stars. Also dM stars have extremely long life times \>50-100 Gyr.
Determining the number of red dwarfs with planets and assessing
planetary habitability (a planet's potential to develop and sustain
life) is critically important because such studies would indicate how
common life is in the universe. Our program - \"Living with a Red
Dwarf\"- addresses these questions by investigating the long-term
nuclear evolution and the magnetic-dynamo coronal and chromospheric
X-ray & FUV/UV properties of red dwarf stars with widely different ages
(\~50 Myr - 12 Gyr). One major focus of the program is to study the
magnetic-dynamo generated coronal and chromospheric X-ray-FUV/UV
emissions and flare properties of a sample of dM0-5 stars. Observations
carried out by FUSE of a number of young to old dM stars provide
important data for understanding Transition-Region heating in these
stars with deep convective zones as well as providing measures of FUV
irradiances. Also studied are the effects of X-ray-FUV emissions on
possible hosted planets and impacts of this radiation on their
habitability. Using these data we are constructing irradiance tables
(X-FUV/UV irradiances) that can be used to model the effects of XUV
radiation on planetary atmospheres and possible life on planetary
surfaces. Here we discuss the initial results of this program.

This research is supported by grants from NASA/FUSE (NNX06AD38G), and
NSF (AST-0507542 & AST-0507536) which we gratefully acknowledge.

**Is there a future in space-based visible/UV spectroscopy?**

Dr. Theodore R Gull NASA Goddard Space Flight Center

Ted.Gull@nasa.gov

The past three decades have provided many advances in space-based
spectroscopy in both the visible and ultraviolet spectral regions. Many
diverse studies have been enabled by multipurpose spectrographs in
spacecraft such as Copernicus, International Ultraviolet Explorer, Far
Ultraviolet Spectrographic Explorer and Hubble Space Telescope. The
latter utilized increasingly improved spectrographs from the Faint
Object Spectrograph and the Goddard High Resolution Spectrograph to the
Space Telescope Imaging Spectrograph and soon the Cosmic Origins
Spectrograph. These instruments have provided increasing capabilities
through detector and optical technology advances.

Space-based spectroscopy offers many advantages: access to the
ultraviolet, no limitations by atmospheric extinction, absorption or
emission and near-diffraction-limited angular resolution. Yet no
space-based, general purpose visible/ultraviolet observatory is planned
for the near term.

As new observatories are considered for the ultraviolet longward of
912A, designs should include near-diffraction imaging spectroscopy
extended through the visible portion of the spectrum. Tradeoffs of
large, monolithic primary mirrors versus segmented telescopes must
consider stability of point spread functions, especially in the studies
of complex, extended sources.

Examples from the HST/STIS studies will be presented, especially of the
massive binary winds of Eta Carinae.

**Far-UV diagnostic wind lines of hot CSPN**

James E Herald The Johns Hopkins University

Luciana Bianchi

herald@pha.jhu.edu

As they transition toward the white dwarf cooling sequence, the fading
winds of Central Stars of Planetary Nebulae (CSPN) are characterized by
very high temperatures (Teff \> 100kK). Determination of wind parameters
of these stars is challenging because their tenuous winds offer few if
any optical spectral diagnostics. Fortunately, the FUSE wavelength range
has revealed new useful wind diagnostics such as high-ionization Iron
and Neon lines. We show examples of results from our ongoing analysis of
hot Galactic CSPN stars.

**Connecting Absorbers and Galaxies: FUV Observations of Strong OVI
Absorber and a Lyman Limit System**

Dr. Chris Howk Univesity of Notre Dame

N. Lehner, J.X. Prochaska, H.A. Kobulnicky, K.L. Cooksey, G.M. Williger

jhowk@nd.edu

With a column density log N(OVI) = 14.95 ± 0.05, the OVI absorber at
z=0.2028 detected in the spectrum of the QSO PKS0312-77 is the strongest
discovered so far in the low redshift Universe. The OVI absorber is
observed near a Lyman limit system (LLS). We present an analysis of
these absorbers and their connection to galaxies based on a combination
of FUV and NUV spectra of PKS0312-77 obtained from FUSE and HST/STIS
E140M/E230M and optical imaging and spectroscopy of galaxies in the
field. Based on OI/HI and a photoionization model, we find a metallicity
of 0.25 solar for the LLS, too enriched to be pristine IGM gas. We find
that the gas resulting from the merger of a 0.7 L\* galaxy (impact
parameter of 38 kpc) is the likely origin for the LLS. At -180 km/s from
the LLS, another absorber is found with a supersolar metallicity.
Outflow from this galaxy is likely responsible for this supersolar,
fully ionized absorber. The metallicity variation is a possible evidence
for poor mixing of metals on galactic structure as observed in the Milky
Way halo. The origin of the strong OVI remains more enigmatic with
plausible origins including an intragroup medium or a galactic corona.

**Far-ultraviolet Spectroscopy of Massive Binaries in the Galaxy and in
the Magellanic clouds**

Rosina C Iping NASA/GSFC & the Catholic University of America

G. Sonneborn, D. Gies S. Williams, D.L. Massa, L. Kaper, G.
Hammerschlag-Hensberge

Rosina.C.Iping@nasa.gov

We report on phase-resolved FUSE observations of three massive colliding
wind binaries in the Galaxy: HD149404 HD93205, and HD93403. The systems
have different masses, eccentricities, and evolutionary states. The
massive O-type binary HD93205 is a double-line spectroscopic system
consisting of an O3.5V and an O8V star in a 6.08-day orbit. HD93403
consists of an O5.5I and an O7V star in a 15.093 day orbit. Both are
located in the Carina OB1 Association. In HD93403, the winds are
comparable in strength, while for HD93205 the wind of the O3.5 star
dominates. HD149404 consists of type O7.5 I(f) and an ON9.7 I star.

We compare these observations with FUSE observations of three HMXRBs,
4U1700-37, SMC X-1 and V801 Cen, and three O-type double-lined
spectroscopic binaries in the Magellanic clouds, LH54-425,
J053441-693139 in the LMC and Hodge 53-47 in the SMC. Improved orbit
parameters, including revised masses, for LH 54-425 are derived from new
CTIO spectroscopy.

Phase-locked wind variability and wind-wind collision effects in the
binaries are studied as traced by changes in terminal velocity and
optical depth of the large number of wind diagnostics in the FUSE
spectral range (O VI, S VI, C III, N III, S III, IV, & VI, P V, Si IV) S
IV, S VI, Si IV and P V lines are important and unique probes of O star
winds because they are strong but not saturated. We determined the Mdot
v_infinity ratio in each system. The spectra provide quantitative and
systematic studies of phase-dependent stellar properties, wind collision
effect and FUV spectrophotometric changes as a function of orbital
phase.

**Multiwavelength Approaches to Understanding Interstellar Dust**

Dr. Adam G Jensen NASA\'s GSFC

Adam.Jensen@colorado.edu

Perhaps more than almost any other subject of astrophysical study, the
interstellar medium can be studied at any wavelength\-\--from gamma rays
to the radio\-\--with each waveband providing unique and significant
information. However, there are substantial limitations on the available
data. One important limitation is that very few lines of sight have been
adequately observed in both wavebands of a potentially enlightening
combination, such as the UV and the IR. This in turn restricts our
understanding of topics as fundamental as interstellar abundances and
dust composition. In this poster, I will review the reasons that such
data limitations exist, what waveband combinations would be useful, what
scientific insight would be gained from those combinations, and what the
prospects are for the future. I will also specifically describe two
accepted observing programs that will, in the near future, utilize a
multiwavelength approach in studying dust. The first is a Chandra/HST
program that will provide unique insight into dust composition by
disentangling the gas-phase and dust-phase abundances of oxygen and
iron. The second is a Spitzer/HST program that will examine the
extinction curves of possible \"translucent clouds\" at wavelengths from
the UV to the IR.

**Implications of SWCX 1/4 keV emission on the LB hot gas in the
galactic disk: Model-Data comparison**

Dimitra Koutroumpa NASA/GSFC

Rosine Lallement, John C. Raymond, Vasili Kharchenko

dimitra.koutroumpa@aerov.jussieu.fr

We present calculations of the heliospheric solar wind charge exchange
(SWCX) emission spectra below 0.3 keV and the resulting contributions of
this diffuse background in the ROSAT 1/4 keV bands. We compare our
results with the soft X-ray diffuse background (SXRB) emission detected
in front of identified shadowing regions during the ROSAT All-Sky Survey
(Snowden et al. 2000). This foreground component is principally
attributed to the hot gas of the so-called Local Bubble (LB), an
irregularly shaped cavity of \~ 50-150 pc around the Sun, which is
supposed to contain \~10\^6 K plasma. Our results suggest that the SWCX
emission from the heliosphere is bright enough to account for most, if
not all the foreground emission at low galactic latitudes, where the LB
is the least extended. However, the SWCX R2/R1 band ratio (1.39) differs
from the data (1.04-1.25), especially in the galactic anti-centre
direction where the observed ratio is the smallest. Assuming that both
SWCX and hot gas emission are present and restricting our modelling to
the low latitudes, we have tested a series of thermal plasma spectra for
different temperatures ranging from 10\^5 to 10\^6.5 K and searched for
a combination of SWCX spectra and thermal emission matching the observed
intensities and band ratios, while simultaneously being compatible with
FUSE OVI emission measurements. In the frame of collisional equilibrium
models, the range we derive for hot gas temperature and emission measure
cannot reproduce the Wisconsin B/C band ratios. Moreover, it is
incompatible with upper limits based on the CHIPS data, and marginally
compatible with EUVE measurements.

**Internal consistency of the FUSE flux calibration: implications for
future missions**

Dr. Jeffrey W. Kruk Johns Hopkins University

Jean Dupuis (CSA), Pierre Chayer (STScI/HIA)

kruk@pha.jhu.edu

The FUSE flux calibration is defined by synthetic spectra of six hot DA
white dwarfs. The six stars include the four DAs used as primary
standards for HST: GD71, GD153, HZ43, and G191-B2B, plus GD659 and
GD246. These stars were chosen to provide a wide range of effective
temperature, 32800K to 61200K, to minimizepotential systematic errors in
the calibration arising from uncertainties in the model parameters for
individual stars and from uncertainties in the theoretical models. The
internal consistency of the HST spectrograph calibrations is impressive,
typically 1-2%, but inherent uncertainties in the FUSE waveband are
greater. We will discuss the internal consistency of the FUSE flux
calibration and present lessons learned from the FUSE experience.

**The FUSE Mission Archival Web Site Moves to MAST**

Karen L Levay MAST/STScI/CSC

W. P. Blair, R. Thompson, M. L. Romelfanger, J. W. Kruk, W. V. Dixon, J.
Caplinger, M. Smith

klevay@stsci.edu

With the close-out of FUSE operations, the long time FUSE web presence
at JHU will soon be closed down. To ensure key project support
information remains available in the long term, FUSE project personnel
are working closely with Multimission Archive at Space Telescope (MAST)
staff to build an improved FUSE archival web site, to be hosted at MAST.
We have been working to identify all meta-data, documentation, website
content and associated products that should be permanently archived.
FUSE staff are rewriting the Data and Instrument handbooks for future
archive users. We are making significant new support information
generally available to users for the first time. These data include
Mission Planning Schedule Timeline Plots (showing each observation as
scheduled in the context of orbital events), Guide Star plots (showing
the anticipated guide stars, field context, and FUSE aperture locations
on the sky), and Science Data Assessment Forms (SDAFs), which contain
information relevant to how the observation actually executed. These
data are being linked into observation Preview pages for easy reference
by archival users. Finally, the entire FUSE science data set, some
nearly 6000 observations, have been reprocessed and re-archived with the
final version of the CalFUSE pipeline, version 3.2. Thus, while some
observations may still benefit from personalized processing, the best
overall automatically-generated data products for all FUSE data will be
available for use in previews and NVO data sets. At this writing, the
transition is in progress, and is expected to be complete by the end of
calendar 2008.

**Additional evidence for deuterium depletion**

Prof Jeffrey L Linsky JILA/University of Colorado and NIST

jlinsky@jila.colorado.edu

In our study of D/H in the Galaxy (ApJ 647, 1106 (2006)), we argued that
the wide range in gas-phase D/H values outside of the Local Bubble could
be explained by deuterium depletion onto dust grains in some lines of
sight. We presented two arguments for this conclusion: a theoretical
argument based on the larger carbon-deuterium binding energy compared
with the carbon-hydrogen bond, and an empirical correlation of low
values of gas-phase D/H with large depletions of such refractory
elements as iron and silicon. One problem with the second argument is
that the depletions were measured relative to neutral hydrogen, but an
unknown amount of hydrogen can be ionized. To avoid this problem we have
compared gas-phase D/H values with column densities of Fe II/P II.
Singly-ionized phosphorus is a useful replacement for the total hydrogen
column density, because (1) P II is the dominant ionization stage over a
wide range of temperatures, (2) phosphorus has a small depletion in the
ISM, and (3) P II is measured in many of the same FUSE spectra used for
measurements of D/H. This work provides additional support for the
deuterium depletion hypothesis. Thus the best test of the amount of
deuterium astration and infall of near primordial gas into the Galactic
disk is the difference between the highest gas-phase D/H measurements
and estimates of primordial D/H.

**Modeling H2 Fluorescence in Planetary Atmospheres with Partial
Frequency Redistribution**

Ms Roxana E Lupu Johns Hopkins University

P.D. Feldman, and S.R. McCandliss

roxana@pha.jhu.edu

We present the modeling of partial frequency redistribution (PRD)
effects in the fluorescent emission lines of molecular hydrogen, the
general computational approximations and the application to planetary
atmospheres. We show that this process produces significant
modifications to the line shape for large optical depths, and estimate
its importance for line radiative transfer and detectability in
astrophysical environments. Our model can be applied to FUSE
observations of Jupiter and Saturn, allowing an independent confirmation
of the H2 abundance and atmospheric structure. The (6-v\") progression
pumped by Ly-beta through the (6-0) P(1) transition is a good candidate
for a fluorescence model with PRD due to the strong variation of the
excitation source over the line profile, translating into the observed
asymmetry of the emission lines.

**The Effects of Clumping on UV Wind Line Diagnostics**

Derck Massa STScI

R. K. Prinja

massa@stsci.edu

By comparing mass loss rates determined from radio, H alpha, and UV
resonance lines, it has become reasonably certain that clumping in OB
star winds affects empirical determinations of their mass loss rates. We
examine three additional UV spectral diagnostics that are sensitive to
clumping and, ultimately, may help constrain its nature. They are:

1\) Doublet ratios of resonance lines.

2\) Deep cusps near terminal velocity in stars with weak winds.

3\) Ratio of the resonance and radiatively excited state lines of

Si IV in certain O9-B0 supergiants.

We present examples of each diagnostic and explain why they respond to
clumping.

**Broad O VI Emission Wings From Active Stars**

Prof James E Neff College of Charleston

Frederick M. Walter (Stony Brook University)

neffj@cofc.edu

The chromospheric and transition region emission lines of the most
active stars have routinely been shown to consist of very broad wings
superimposed on the narrower, rotationally-broadened emission core. If
these wings are attributed to a single emission mechanism in the stellar
atmosphere, the implied thermal broadening often strains credibility. If
they are due to active regions or loops rotating into and out of view,
they should be present only for a small range of rotational phase. They
have also been attributed to continuous flaring and to circumstellar
material (loops, disks, etc.). We have been analyzing spectra of very
active stars in the FUSE continuous viewing zone, allowing them to be
observed continuously over one or more complete rotations. This helps to
distinguish between spatial (repeatable, phase-dependent) and temporal
variations and provides further insight into the mechanism(s)
responsible for the broad wing emission. For example, in observations
spanning 3 rotational cycles of AB Dor in December 2003, we observe a
phase-dependent velocity shift between the narrow and broad emission
components of the O VI lines. We will discuss the contributions FUSE
spectra have made to resolving the origin of the broad emission
components.

**Eta Car: The good, the bad and the ugly of nebular and stellar
confusion**

Dr. Krister E Nielsen Catholic University of America

G. Kober (CUA) , T. Gull (GSFC), R. Iping (CUA), J. Hillier (U. Pitt.) &
G. Sonneborn (GSFC)

nielsen@milkyway.gsfc.nasa.gov

Observations in the far UV provide a unique opportunity to investigate
the massive star Eta Car and its hot binary companion. Eta Car was
observed with FUSE over a large portion of the 5.54 year spectroscopic
period before and after the 2003.5 minimum. The observed spectrum is
defined by strong stellar wind signatures, primarily from Eta Car A,
complicated by the strong absorptions of the ejecta surrounding Eta Car
plus interstellar absorption. The Homunculus and Little Homunculus are
massive bipolar ejecta historically associable with LBV outbursts in the
1840s and the 1890s and are linked to absorptions at -513 and -146 km/s,
respectively. The FUSE spectra are confused by the extended nebulosity
and thermal drifting of the FUSE co-pointed instruments. Interpretation
is further complicated by two B stars sufficiently close to Eta Car to
be included most of the time in the large FUSE aperture. Follow up
observations partially succeeded in obtaining spectra of at least one of
these B stars through the smaller apertures, allowing potential
separation of the B star contribution and Eta Car. A complete analysis
of all available spectra is currently underway. Our ultimate goals are
to directly detect the hot secondary star, if possible, with FUSE and to
identify the absorption contributions to the overall spectrum.

**Spectral Analysis of the sdOB Primary of the Post-Common-Envelope
Binary LB 3459 (AA Dor)**

Dr. Thomas Rauch Kepler Center for Astro and Particle Physics

Johannes Fleig, Klaus Werner, Jeffrey W. Kruk

rauch@astro.uni-tuebingen.de

LB 3459 is an eclipsing, close, post common-envelope binary consisting
of a sdOB primary star and an unseen secondary with an extraordinary
small mass - formally a brown dwarf. A recent NLTE spectral analysis
shows a discrepancy to the surface gravity which is derived from
analyses of radial-velocity and light curves. One probable reason for
this \`\`gravity problem\'\' might be a too-low surface gravity
previously determined from optical and near UV observations of LB
3459.We present results of a detailed spectral analysis of the FUSE
observation of LB 3459 by means of state-of-the-art NLTE
model-atmosphere techniques.

**The Evolution of O(He) Stars**

Dr. Thomas Rauch Kepler Center for Astro and Particle Physics

Klaus Werner, Jeffrey W. Kruk

rauch@astro.uni-tuebingen.de

Spectral analyses of H-deficient post-AGB stars have shown that a small
group of four extremely hot objects exists which have almost pure He
absorption-line spectra in the optical. These are classified as O(He)
stars. For their evolution there are two scenarios: They could be the
long-sought hot successors of RCrB stars, which have not been identified
up to now. If this turns out to be true, then a third post-AGB
evolutionary sequence is revealed, which is probably the result of a
double-degenerate merging process. An alternative explanation might be
that O(He) stars are post early-AGB stars. These depart from the AGB
just before they experience their first thermal pulse (TP) which will
then occur as a late thermal pulse (LTP). This would be a link to the
low-mass He-enriched sdO stars and low-mass, particularly He-rich PG
1159 stars. We present results of a spectral analysis of FUSE
observations of the O(He) stars by means of NLTE model-atmosphere
techniques and summarize our present picture of their evolutionary
scenario.

**The Impact of FUSE on our Understanding of Stellar Post-AGB
Evolution**

Dr. Thomas Rauch Kepler Center for Astro and Particle Physics

Klaus Werner, Lars Koesterke, Jeffrey W. Kruk, Cristina M. Oliveira

rauch@astro.uni-tuebingen.de

State-of-the-art non-LTE spectral analysis requires high-resolution and
high-S/N observations of strategic metal lines in order to achieve
reliable photospheric parameters like, e.g., effective temperature,
surface gravity, and element abundances. Hot stars with effective
temperatures higher than about 40000 K exhibit their metal-line spectrum
arising from highly ionized species predominantly in the (far)
ultraviolet wavelength range. FUSE observations of hot, compact stars
provided the necessary data. With these, it has been, e.g., possible to
identify fluorine for the first time in observations of post-AGB stars.
The evaluation of ionization equilibria of highly ionized neon,
phosphorus, sulfur, and argon provides a new sensitive tool to determine
effective temperatures of the hottest stars precisely. Moreover,
abundance determinations have put constraints on stellar evolutionary
models which, in turn, have improved greatly our picture of stellar
post-AGB evolution. We present highlights of our spectral analyses in
the recent years which are based on FUSE observations.

**Far Ultraviolet Spectroscopic Explorer Observations of OB Stars in the
Magellanic Clouds**

Ms Eliceth Rojas Universidad Central de Venezuela / STScI

Nolan R. Walborn, Alex W. Fullerton

sadr16@gmail.com

The Far Ultraviolet Spectroscopic Explorer has provided an extensive
sample of Magellanic Cloud OB spectra in the 900-1200 A range. The
shorter wavelengths are more accessible in the Clouds than in the
Galaxy, because of the lower interstellar extinction and absorption.
Many additional objects have been observed since the initial compilation
by Walborn et al. (ApJS 141, 443, 2002). These new data have been
reduced and organized into spectral-type sequences, some of which are
presented here, including several objects of special interest.

**The Extension of the Transition Temperature Interstellar Plasma into
the Lower Galactic Halo**

Dr. Blair D Savage University Wisconsin, Madison

Bart Wakker and David Bowen

savage@astro.wisc.edu

Column densities for H I, Al III, Si IV, C IV, and O VI toward 109 stars
and 30 extragalactic objects have been assembled in order to study the
relative extensions of these species away from the Galactic plane into
the Galactic halo. H I and Al III trace the warm neutral and warm
ionized medium, respectively, while Si IV, C IV and O VI trace a
combination of warm photoionized and collisionally ionized transition
temperature plasma. The large object sample allows us to consider and
correct for the effects of the sample bias that has affected the results
of earlier but smaller surveys of the gas distributions. We find Si IV
and C IV have similar exponential scale heights of \~3.2 to 3.6 kpc. The
scale height of O VI is marginally smaller with h\~ 2.6 kpc. The
transition temperature gas is \~6 times more extended than the warm
ionized medium traced by Al III with h \~ 0.65 kpc and \~14 times more
extended than the warm neutral medium traced by H I with h \~ 0.21 kpc.
There is a factor of 2 decrease in the dispersion of the ionic column
density ratios for transition temperature gas for lines of sight in the
Galactic disk compared to extragalactic lines of sight through the
entire halo. The logarithmic dispersions for N(C IV)/N(O VI) and N(Si
IV)/N(O VI) are approximately twice that found for N(Si IV)/N(C IV). The
observations are compared to the predictions of the various models for
the production of the transition temperature gas in the halo.

**Preparation of a Far-UV Spectral and Line Atlas for B III=III Stars**

Dr. Myron A Smith Catholic University of America

msmith@stsci.edu

B type stars are major contributors to the total far-UV flux (950-1125
Å) produced in the Milky Way and external galaxies. The final processing
of the Far Ultraviolet Spectroscopic Explorer (FUSE) dataset, together
with the the existing archives of the International Ultraviolet Explorer
(IUE) high dispersion spectra and the Copernicus Atlas of tau Sco,
permit the construction of an atlas of 10 sharp-lined main sequence
(class III-V) B stars. We are building an atlas denoting the H I and
molecular H2 features separately from photospheric lines and listing
essentially all noticeable absorption features with known oscillator
strengths. This atlas will allow investigators to identify anomalous
features in other B-type spectra as well as to select lines that can
serve as proxies for the determination of Teff, anomalous abundance
patterns, and possible departures of the star\'s atmospheric T(tau) from
nonstandard gradients. We discuss the input constituents for this atlas.
We also show three examples of the atlas panels, showing photospheric
line identifications for types B0V, B2V, and B8V. The \~3600 lines we
have identified comprise over 11% of the list used in our line library.
We have been unable to identify only ≈5% of the visible features for the
tau Sco spectrum, and fewer still for the B8 spectrum. A comparable
number of lines is found to be overpredicted.

**Far-UV Temperature Diagnostics for Hot Central Stars of Planetary
Nebulae**

Dr. George Sonneborn NASA\'s Goddard Space Flight Center

Rosina C. Iping (CUA & NASA/GSFC) and James Herald (JHU)

george.sonneborn@nasa.gov

The effective temperatures of hot central stars of planetary nebulae are
usually determined from the ratios of optical He II lines. However,
far-ultraviolet spectra from the FUSE satellite of several hot (Teff \>
70,000 K) hydrogen-rich central stars have stellar features that imply a
significantly hotter effective temperature than that determined from He
II. There are many stellar features in the long wavelength portion of
the FUSE spectrum. These include O VI 1146-47, F VI 1039.5, Fe VII
1118.6, 1141.4, Fe VI 1120.9, 1131.5, and Ni VI 1124.2, 1148.2. The
strong F VI 1139.5 line is of interest because of the large
overabundance (over 100X solar) of F in some PG1159 stars reported by
Werner et al. (2005). Modeling of these spectral feature provide an
independent method for measuring the effective temperatures of these
stars. An example of HD 200516, the central star of NGC 7009 (Teff =
82000 K from optical He II line ratios vs 95000 K from Far-UV metal
lines) is presented. This difference in Teff implies a large increase in
the EUV ionizing radiation field and is important for photoionization
modeling of the planetary nebula.

**Search for O VI Emission from the Shocked Circumstellar Gas of SN
1987A**

Dr. George Sonneborn NASA\'s Goddard Space Flight Center

R. C. Iping (CUA & NASA/GSFC), P.Lundqvist, C. Fransson (Stockholm
University)

george.sonneborn@nasa.gov

The Far Ultraviolet Spectroscopic Explorer (FUSE) was used to search for
broad O VI emission from the shock interaction zones produced by the
collision of high-velocity supernova ejecta with the dense inner
circumstellar ring of SN 1987A. Since the shock interaction with the
inner ring began in 1997, broad (FWHM = 300 km/sec) emission from
optical coronal lines (e.g. \[Fe X\], \[Fe XI\], and \[Fe XIV\]) has
emerged and increased exponentially in strength. O VI 1032-1038 A
emission is expected to track the coronal lines. O VI is also expected
to be the primary cooling transition for the million-degree shocked gas.
An accurate measurement of the O VI line strength would significantly
improve current models of the shock interaction. FUSE observations of SN
1987A in 2000 and 2001 did not detect broad O VI due to spectral
contamination from two early-type stars within a few arc seconds of the
SN. However, O VI emission was detected with narrow line widths (FWHM
less than 35 km/sec) and a heliocentric radial velocity of +280 km/sec.
This places the emitting gas at rest relative to the supernova and is
interpreted as emission from unshocked circumstellar gas. The last FUSE
observation of SN 1987A was obtained in May 2007 and used a narrow slit
(1.25x20 arcsec) to significantly reduce the spectral contamination from
the two early-type stars. Yet the 2007 spectrum does not reveal and
significant O VI emission. The implications of these results are
discussed.

**Ultraviolet studies of Classical and Recurrent Novae in Outburst**

Prof. Sumner Starrfield Arizona State University

K. Vanlandingham, G. Schwarz, S. Shore, G. Sonneborn

starrfield@asu.edu

Studies of the Classical Nova Outburst in the ultraviolet have been
ongoing since the advent of space based UV astronomy. While sporadic
observations occurred before the International Ultraviolet Explorer
Satellite (IUE), the data from this satellite resulted in huge advances
in our understanding of the outburst. For example, we discovered two
compositional classes of novae, those that occurred on a carbon-oxygen
white dwarf and those that occurred on an oxygen-neon white dwarf. We
were also able to use these data to determine ejecta masses and the
energetics of the outburst to a far higher accuracy than before. One of
the highlights of the IUE studies were the detailed observations of the
outburst of RS Oph in 1985. These data confirmed that the outburst was
caused by a thermonuclear runaway on the white dwarf and that the
characteristics of the explosion were a result of the ejected material
running into the outer layers of the giant companion. I will review
these results and suggest necessary observations that could be done by a
future UV spacecraft

**High-Stage Ions in the ISM from Supernova Remnants: Role of
Anisotropic Thermal Conduction**

Dr. David A Tilley University of Notre Dame

Dinshaw S. Balsara, J. Christopher Howk

dtilley@nd.edu

We use 2.5D numerical simulations to explore the production of hot gas
and transitional gas from supernova remnants in the presence of
flux-limited anisotropic thermal conduction and equilibrium cooling. We
have followed the evolution of supernova remnants embedded in a variety
of environments representative of the interstellar medium, over several
millions of years. We track the volume, luminosity, line widths and
dosages of the FUSE-sensitive ions O VI, O VII and O VIII over the
entire time that this hot gas persists, using an equilibrium ionization
model. We demonstrate that anisotropic thermal conduction can moderate
the temperature of the hot gas and increase the luminosity of high-stage
ions of oxygen that are deposited into the interstellar medium. We also
show that the magnetic field can have a role in reheating the gas long
after the initial supernova event.

**Testing binary population synthesis models with hot subdwarfs**

Dr. Richard A Wade Pennsylvania State University

Ravi Kumar Kopparapu, R. O\'Shaughnessy

wade@astro.psu.edu

Models of binary star interactions have been successful in explaining
the origin of field hot subdwarf (sdB) stars in short period systems.
The hydrogen envelopes around these core He-burning stars are removed in
a \"common envelope\" evolutionary phase. Reasonably clean samples of
short-period sdB+WD or sdB+dM systems exist, that allow the common
envelope ejection efficiency to be estimated for wider use in binary
population synthesis (BPS) codes. About one-third of known sdB stars,
however, are found in longer-period systems with a cool G or K star
companion. These systems may have formed through Roche-lobe overflow
(RLOF) mass transfer from the present sdB to its companion. They have
received less attention, because the existing catalogues are believed to
have severe selection biases against these systems, and because their
long, slow orbits are difficult to measure. Are these known sdB+cool
systems worth intense observational effort? That is, can they be used to
make a valid and useful test of the RLOF process in BPS codes? We use
the Binary Stellar Evolution (BSE) code of Hurley et al. (2002), mapping
sets of initial binaries into present-day binaries that include sdBs,
and distinguishing \"observable\" sdBs from \"hidden\" ones. We aim to
find out whether (1) the existing catalogues of sdBs are sufficiently
fair samples of the kinds of sdB binaries that theory predicts, to allow
testing or refinement of RLOF models; or instead whether (2) large
predicted hidden populations mandate the construction of new catalogues,
perhaps using wide-field imaging surveys such as 2MASS, SDSS, and Galex.
We also report on a pilot study to identify hidden subdwarfs, using
2MASS and GALEX data. Supported in part by NASA and NSF.

**The Soft X-ray Background - OVI Connection Solved!**

Dr. Barry Y Welsh Space Sciences Laboratory, UC Berkeley

Prof. Martin Barstow, Rosine Lallement and David Boyce

bwelsh@ssl.berkeley.edu

There has been much recent controversy regarding the physical state of
the interstellar gas located within the Local Cavity. Observations of
the Soft X-ray background emission and local OVI absorption have long
implied that the Local Cavity is filled with a hot gas. However new data
on local OVI absorption and the recent recognition of the importance of
solar wind charge exchange processes with regard to the production of
soft X-rays in the heliosphere pose serious problems with the
aforementioned accepted picture of a hot Local Cavity. We present a new
model of the Local Cavity which can explain (i) the observed
distribution of soft X-ray background emission, (ii) the observed
distribution of local OVI absorption, (iii) the solution to the Local
Cavity \"pressure\" problem, (iv) the importance of the Local Chimney
with regard to infalling hot gas from Loop I, and (iv) the importance of
local magnetic fields.

**HIRDES - The High-Resolution Double-Echelle Spectrograph for WSO/UV**

Klaus Werner University of Tuebingen, Germany

J. Barnstedt, N. Kappelmann, H. Becker-Ross, S. Florek

werner@astro.uni-tuebingen.de

The World Space Observatory Ultraviolet (WSO/UV) is a multi-national
project grown out of the needs of the astronomical community to have
future access to the UV range. WSO/UV consists of a single UV telescope
with a primary mirror of 1.7m diameter feeding the UV spectrometer and
UV imagers. The spectrometer comprises three different spectrographs,
two high-resolution echelle spectrographs (the High-Resolution
Double-Echelle Spectrograph, HIRDES) and a low-dispersion long-slit
instrument. Within HIRDES the 102-310nm spectral band is split to feed
two echelle spectrographs covering the UV range 174-310nm and the
vacuum-UV range 102-176nm with high spectral resolution (R\>50,000). The
technical concept is based on the heritage of two previous ORFEUS SPAS
missions. The phase-B1 development activities are described.

**Highly Ionized HVCs in the Inner Galaxy: Evidence for a Galactic
Origin**

Mr. William F Zech University of Notre Dame

Nicolas Lehner, J. Christopher Howk, W. Van Dyke Dixon, Thomas M. Brown

wzech@nd.edu

Highly-ionized high-velocity clouds have been studied for the last
decade. Some lines of reasoning have suggested an extragalactic origin
for these clouds, placing them near the outskirts of the Milky Way or
Local Group, and some models have explored the possibility that they may
be associated with dark matter minihalos. We have observed
highly-ionized HVCs toward the inner Galaxy globular cluster Messier 5
that appear to have a Galactic origin. Here we present FUSE and STIS
observations of the post-AGB star ZNG 1 in M 5 (l=3.9, b=47.7; d=7.5
kpc, z=+5.3 kpc). Absorption is seen in OVI, CIV, SiIV, and lower
ionization species at LSR velocities near -140 and -110 km/s.
Photoionization models and path length arguments rule out the
possibility that this gas is circumstellar. The metallicity of these
HVCs is \[O/H\] = +0.22+/-0.10, the highest of any known HVC. Given the
metallicity and distance constraints, we conclude that these HVCs have a
Galactic origin. We hypothesize that these HVCs are part of a
large-scale circulation and may be related to a Galactic nuclear wind.
This work has appeared in Zech et al. (2008, ApJ, 679, 460).

**Highly Ionized Envelopes of High Velocity Clouds**

Erin E Zekis University of Colorado at Boulder

J. Michael Shull

ezekis@colorado.edu

We present recent results on highly ionized gas in Galactic
High-Velocity Clouds (HVCs), originally surveyed in O VI (Sembach et al.
2003). In a new FUSE/HST survey of Si II/III/IV (Jones, Shull, et al.
2008) toward 37 AGN, we detected Si III (1206.500 A) absorption with a
sky coverage fraction 78 ± 5% (61 HVCs along 29 of 37 high-latitude
sight lines). The Si III (1206.500 A) line is typically 4-5 times
stronger than O VI (1031.926 A). The mean HVC column density per sight
line, log N(Si III) = 13.44 ± 0.21, corresponds to a column density of
perhaps 1019 cm-2 of low-metallicity (10-20% solar) ionized gas in the
low halo. Recent determinations of HVC distances allow us to estimate a
total reservoir of 108 M_sun. Estimates of infall velocities indicate an
infall rate of perhaps 1 M_sun yr-1, comparable to the replenishment
rate for star formation in the disk. HVCs appear to be sheathed by
intermediate-temperature gas (104.0 - 104.5 K) detectable in Si III, Si
IV, as well as in O VI and other high ions. To prepare for HST
observations of 10 HVC-selected sight lines with the Cosmic Origins
Spectrograph (COS), we compile FUSE/STIS spectra of these ions, plus Fe
III, C III, C IV, and S IV. Better constraints on the physical
properties of HVC envelopes and a careful treatment of HVC kinematics
and mass infall rates will come from high-quality (S/N = 30-40) COS
data.

**Spatially Resolved Far-Ultraviolet Spectroscopy of the Nuclear Region
of NGC 1068**

Dr. Wei Zheng Johns Hopkins University

J.-X. Wang, G. A. Kriss, D. Sahnow, M. Allen, M. Dopita, Z. Tzvetanov,
G. Bicknell

zheng@pha.jhu.edu

We carry out high-resolution FUSE spectroscopy of the nuclear region of
NGC 1068. The first set of spectra was obtained with a 30\" square
aperture that collects all emission from the narrow-line region. The
data reveal a strong broad O VI component of FWHM 3500 kmsˉ¹ and two
narrow O VI 1031/1037 components of 350 kmsˉ¹. The C III 977 and N III
991 emission lines in this spectrum can be fitted with a narrow
component of FWHM 1000 kmsˉ¹ and a broad one of 2500 kmsˉ¹. Another set
of seven spatially resolved spectra were made using a long slit of
1.\"25×20\", at steps of 1\" along the axis of the emission-line cone.
We find that (1) Major emission lines in the FUSE wavelength range
consist of a broad and a narrow component; (2) There is a gradient in
the velocity field for the narrow O VI component of 200 kmsˉ¹ from 2\"
southwest of the nucleus to 4\" northeast. A similar pattern is also
observed with the broad O VI component, with a gradient of 3000 kmsˉ¹.
These are consistent with the HST/STIS findings and suggest a biconical
structure in which the velocity field is mainly radial; (3) A major
portion of the C III and N III line flux is produced in the compact
core. and (4) The best-fitted UV continuum suggests virtually no
reddening, and the He II 1085/1640 ratio suggests a consistently low
extinction factor across the cone.

## The Roles of the Invited Speakers and the Provocateurs

The Invited Speakers have been asked to present a discussion of their
subject based on measurements made by FUSE and other ultraviolet
observatories, their connection with measurements made with other
techniques and, where appropriate, the implications of the low-z
measurements for high-z phenomena. We are seeking to not only celebrate
the accomplishments of the FUSE mission and understand the status of
this field, but to look forward and understand the major scientific
drivers for the ultraviolet capabilities of the next generation of space
observatories.

The leadership of the Provocateurs in the discussion will enhance the
progress of the conference towards these goals. We will ask
knowledgeable leaders in major topic areas to lead and stimulate
significant discussions during each session, addressing such questions
as: Where does this field stand at this time? What progress will be made
in the coming years? Looking further ahead, what capabilities will be
needed in a future ultraviolet observatory to make significant progress?

Toward that end, in addition to the usual question period at the end of
each talk, we have incorporated an additional 15 minute period into each
session for a Provocateur-led discussion.

<http://futureofuv.gsfc.nasa.gov/>