bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematics of the Circumnuclear Region of NGC 3351
Authors: Díaz A. I. , Hägele G. F. , Cardaci M. V. , Terlevich E. , Terlevich R.
Published: April 2007

Using high-resolution blue and far red spectra from the William Herschel Telescope, we have mapped the velocity field along three different slits in the central kiloparsec of the spiral galaxy NGC 3351. We have measured ionized gas (Hβ and [Oiii]) and stellar (near-IR Ca triplet) velocity dispersions for five individual Circumnuclear Star Forming Regions (CNSFRs) and the nucleus. Velocities and velocity dispersions in the red range were obtained using the cross-correlation technique of Tonry & Davis (1979AJ.84.1511) with a set of eleven templates, following the work by Nelson & Whittle (1995.ApJSS.99.67) with the variations introduced by Palacios et al. (1997.A & A.323.749). The gas velocities and velocity dispersions have been measured by fitting gaussians to the emission lines (Hβ and [OIII] λ5007Å) using three different suitable continua chosen by visual inspection and taking the average of the three results (Jiménez-Benito et al., 2000.MNRAS.317.907).

The rotation velocities derived for gas and stars are in very good agreement, although in some cases the gas seems to rotate slightly faster than stars. The turnover points of the rotational curves seem to be located at the same position than the star forming ring as found in other galaxies (Díaz, R. et al., 1999ApJ.512.623). The derived values are consistent with those previously obtained for the systemic velocity of NGC 3351 (Planesas et al., 1997.A & A.325.81).

The velocity dispersions of the stars are always larger (by between 10 and 25 km/sec) than those derived from Hβ emission lines. In the cases in which it has been possible to use the Paschen emission lines, the results obtained are similar. The twice ionized oxygen, on the other hand, shows velocity dispersions comparable to the stellar ones or, in some cases, even larger. It is however important to point out that in these metal rich regions the [Oiii] lines are very weak and they have a poor signal to noise ratio, then it is more difficult to accurately estimate the global kinematic behaviour from this emission line.

The difference between the behavior of ionized hydrogen and stars could be interpreted by assuming that the gas is confined to the disc and supported by rotation while the stars are mostly supported by dynamical pressure (see Pizzella et al., 2004.A & A.424.447). However, the kinematics of ionized gas as mapped by [Oiii], as we mentioned above, is similar to that of the stellar component.

We have applied the virial theorem to estimate the dynamical masses of the clusters and the galactic nucleus, assuming that the systems are gravitationally bound and spherically symmetric, and using sizes measured from the HST-WFPC2 image in the F606W filter (sizes between 2.6 and 5.1 pc). These values of the masses, estimated from stellar velocity dispersion measurements as mapped by the CaT lines, are in the range between 5.1×106 and 5.0×107 M⊙ for the five studied CNSFRs and 3.6×107 M⊙ for the nucleus of the galaxy, in the inner 23.4 pc.
A Link in SFR and Morphology of Bulges
Authors: Fisher David B.
Published: April 2007

We use Spitzer 3.6-8.0 μm color profiles to compare the radial structure of star formation of galaxies with pseudobulges and classical bulges. Galaxies structurally identified as having pseudobulges have higher central star formation rates than those of classical bulges. Further, galaxies identified as having classical bulges have remarkably regular star formation profiles. These observations support the picture of pseudobulge formation via secular evolution and classical bulges forming in mergers.
Star-Forming Regions in the SMC
Authors: Gonidakis I. , Livanou E. , Kontizas E. , Klein U. , Kontizas M. , Kester D. , Fukui Y. , Mizuno N. , Tsalmantza P.
Published: April 2007

SMC has been going through an active star formation epoch, especially during the last 0.2 Gyr when the close encounter with the LMC occured. Our goal is to detect regions dominated by early-type stars and gas and examine their behaviour at different wavelengths. Spectral energy distributions, a colour-magnitude diagram and a two-colour diagram from IRAS data (Bontekoe, Koperet & Kester (1994); Bontekoe, Kester, Stanimirović, et al. (1999)) for these regions were used in order to compare their properties with those of starburst galaxies (Helou (1986); Lehnert & Heckman (1995)). We have selected 50 stellar complexes with increased 100-μm IRAS flux, with detetected emission in all IRAS bands and/or high concentration of young stars. Ranking them by size (Maragoudaki, Kontizas, Kontizas, et al. (1998)), a total of what we call 24 aggregates, 23 complexes and 3 super-complexes were found. Radio continuum maps at 8.6-GHz (Haynes, Murray, Klein, et al. (1986)) and the CO (1→0) line (Mizuno, Rubio, Mizuno, et al. (2001)) were also correlated with the map of the complexes. Only 8 of them show enhanced star formation activity according to their IR properties and 8.6-GHz map, however, none of them resembles the IR behaviour of starburst regions found in the LMC and starburst galaxies (Livanou, Kontizas, Gonidakis, et al. (2006)). The south-west part of the “bar” has the most diverse intensity of star formation, with CO emission coincident with the largest structure. In the north-eastern end of the “bar”, star formation is likely to have commenced in the recent past, with molecular gas being abundant in this region. Ongoing and future star formation are revealed in the wing, while it appears to have ceased in the central “bar”.
A Possible Detection of CO (J = 3–2) Emission From the Host Galaxy of GRB 980425 with Atacama Submillimeter Telescope Experiment
Authors: Hatsukade Bunyo , Kohno Kotaro , Endo Akira , Tosaki Tomoka , Ohta Kouji , Sakamoto Seiichi , Kawai Nobuyuki , Cortés Juan R. , Nakanishi Kouichiro , Okuda Takeshi , Muraoka Kazuyuki , Sakai Takeshi , Ezawa Hajime , Yamaguchi Nobuyuki , Kamegai Kazuhisa , Kawabe Ryohei
Published: April 2007

Long-duration gamma-ray bursts (GRBs) are considered to be due to the death of massive stars. Therefore, GRBs are closely associated with the star formation of host galaxies. Since GRBs can be detected at cosmological distances, they are expected to be probes of the star formation history of the Universe. In order to determine the use of GRBs, it is essential to understand the star formation of their hosts. Multi-wavelength observations have shown that the star formation rates (SFRs) of GRB hosts derived from submillimeter/radio observations are generally higher than those from optical/UV observations (Berger et al. 2003). This implies that GRB hosts have a large amount of molecular gas and massive star formation obscured by dust. In order to solve this problem, it is necessary to derive the SFRs in a method which is independent of existing methods and not affected by dust extinction.

We observed 12CO (J = 3–2) line emission from the host galaxy of GRB 980425 using the Atacama Submillimeter Telescope Experiment (ASTE). Five points were observed covering the entire region of the galaxy, and we find possible emission features (S/N ~ 3 σ) at the velocity range corresponding to the redshift of the galaxy. By combining all spectra of five points, we obtain a global spectrum with a ~4 σ emission feature. If the features are real, this is the first detection of CO among GRB hosts. We derive the total gas mass of M(H2)=7 ± 2× 108M⊙ assuming a CO-to-H2 conversion factor of αCO = 8.0M⊙ (K km s−1 pc2)−1, which is deduced using the correlation between the αCO and the metallicity. The dynamical mass is calculated to be Mdyn=2× 1010M⊙, and M(H2)/Mdyn~3% is consistent with those of nearby dwarfs and normal spirals. The derived SFR is 0.5 ± 0.1 M⊙ yr−1 based on the Schmidt law. This SFR agrees with the results of previous Hα observations, suggesting that there is no significant obscured star formation in this host galaxy. This result implies that there is a variety of GRB hosts in terms of the presence of obscured star formation.
A Comparison of Chemical Evolution between the Milky Way and M31 Galaxy
Authors: Yin J. , Hou J.L. , Chang R.X. , Boissier S. , Prantzos N.
Published: April 2007

Andromeda galaxy (M31,NGC224) is the biggest spiral in the Local Group. By studying the star formation history(SFH) and chemical evolution of M31, and comparing with the Milky Way Galaxy, we are able to understand more about the formation and evolution of spiral galaxies.
N-Body Simulations of Galaxies: Mass-Loss from Old Stellar Populations and the Mass Budget of the Central Kiloparsec
Authors: Jungwiert Bruno
Published: April 2007

We give estimates of the global mass-loss rate from bulge stars and show that this supply of gas is not negligible for the mass budget of the central kiloparsec in comparison with mass inflow rate predicted by N-body simulations of barred galaxies and mergers.
The Last Stages of Star Formation in dEs?
Authors: Lisker T. , Glatt K. , Westera P. , Grebel E. K.
Published: April 2007

A significant fraction of Virgo cluster early-type dwarf galaxies have blue central colours caused by recent or ongoing star formation. A spectral analysis shows that even in their centers, stellar mass is dominated by an old population. These galaxies are an unrelaxed cluster population that possibly formed from morphological transformation of late-type galaxies.
Star-Burst Regions in the LMC
Authors: Livanou E. , Kontizas M. , Gonidakis I. , Kontizas E. , Klein U. , Fukui Y. , Mizuno N.
Published: April 2007

Filamentary structures of early type stars are found to be a common feature of the MCs formed ~0.9 − 2 × 108yr ago. As we go to younger ages these large structures appear fragmented and sooner or later form young clusters and associations. In the optical domain we have detected 56 such large structures of young objects, known as stellar complexes in the LMC (Maragoudaki, Kontizas, Kontizas, et al. (1998)) and investigate their properties. IRAS data of the LMC stellar complexes were compared with observations of starburst galaxies (Helou (1986); Lehnert & Heckman (1996)). It has been found that nearly 1/4 of the stellar complexes are extremely active resembling the IR behaviour of starburst galaxies and HII regions. These stellar complexes are called here “starburst regions”. They host an increased number of HII regions, SNRs, stellar associations and nebulae. The main starburst tracers are their IR luminosity F60 and the 8.6-GHz radio emission (8.6-GHz data: Dickel, McIntire, Gruendl, et al. (2005)). In Table 1 the characteristics of the various types of complexes are given. Finally the evolution of all stellar complexes is discussed based on the CO emission (CO data: Fukui, Mizuno, Yamagushi, et al. (1999)). More than 50% of the starburst and starburst candidate regions show enhanced CO emission, indicating ongoing and future evolution.
Star Formation History of the Dwarf Galaxies in the Centaurus A Group
Authors: Makarova L. , Makarov D. , Dolphin A. , Karachentsev I. , Tully B. , Sakai S. , Shaya E. , Rizzi L. , Sharina M. , Karachentseva V.
Published: April 2007

We derive quantitative star formation histories (SFH) of the two dwarf spheroidal (KK 197 and ESO 269-066) and one dwarf irregular (ESO 381-018) galaxies in the nearby Centaurus A group. The data are part of our sample of about 50 nearby dwarf galaxies observed with the Advanced Camera for Surveys (ACS) at the Hubble Space Telescope (prog. 9771 & 10235, PI I.Karachentsev). Deep color-magnitude diagram (CMD) of KK 197 is shown in Fig.1.
The Kinematics of Extended Hα Emission in Blue Compact Galaxies
Authors: Marquart T. , Östlin G. , Bergvall N. , Masegosa P. , Amram P. , Márquez I.
Published: April 2007

Blue Compact Galaxies (BCGs) have received interest mainly because they comprise the best available test-beds for studies of low-metallicity star formation (SF) and allow the study of relatively unevolved systems at low redshift. Their ongoing phase of intense star formation is a transient phenomenon and the best candidates for its trigger are interactions and mergers. Studies of the kinematics are important for the understanding of this process.

We present spatially resolved kinematics from the Hα line in five BCGs that show an extended region of ionised emission around the central starburst. We find this region to have near-spherical isophotes at large radii and to be dynamically decoupled from a central disturbance. A scenario where the strong triggered star formation in the center ionises the surrounding gas cloud, still following its original motions, can qualitatively explain these common features. The poster, including the figures, can be found at http://kern-2pt/thomasmarquart.net/pspdf/prague-marquart.pdf.
Obscured Supernovae in Starburst Galaxies
Authors: Mattila Seppo , Meikle Peter , Greimel Robert , Väisänen Petri
Published: April 2007

About one core-collapse supernova (CCSN) is expected to explode every 5–10 years in the nuclear regions of M 82 and other nearby starburst galaxies. In luminous infrared galaxies (LIRGs) such as the interacting system Arp 299 (NGC 3690 + IC 0694) at least one CCSN can be expected every year. Due to the high dust extinction most of these SNe have remained undetected. Here we show results from two near-IR searches we have recently carried out to detect obscured SNe in nearby starburst galaxies and LIRGs.
Serendipitous Spectroscopic Detection of Faint Galaxies at MIR with the IRC Onboard the AKARI During Its In-orbit PV Period
Authors: Ohyama Y. , Wada T. , Sakon I. , Ishigaki M. , Onaka T. , Oyabu S. ,   AKARI/IRC team
Published: April 2007

The InfraRed Camera (IRC) (Onaka et al. 2004), a wide-field (~10 × 10 arcmin2) NIR-MIR 2–26(μm) camera and spectrograph onboard the AKARI (formerly ASTRO-F) space telescope (Murakami et al. 2004), can perform slit-less spectroscopic survey. Many faint galaxies have been serendipitously detected during its in-orbit performance verification period thanks to the power of the slit-less spectroscopy. They are as faint as a few – several mJy in flux, but they can be easily recognized by their prominent spectroscopic features (e.g., PAH). Their redshift (≲0.3) can be measured through spectral template fitting over the features. We can thus obtain their basic information (redshift, activity type, and luminosity) to investigate nature of galaxies out to much greater distance at MIR than before. With the new IRC/AKARI data, we might be able to address some of the most interesting questions on galaxy evolution at z≃0.3–2 (e.g., Genzel & Cesarsky 2000; Peeters et al. 2004; Pearson 2005): What contributes to the excess found in mid-infrared source count studies with ISO/Spitzer surveys? How does the luminosity function evolve with redshift? How do the spectral features (PAH, etc.) evolve with redshift, and how they correlate with MIR and FIS luminosities with each other? We here demonstrate how MIR galaxy spectra thus obtained are useful for investigation of their basic properties.
Photometric Structure and Star Formation in Blue Compact Dwarf Galaxies
Authors: Papaderos P.
Published: April 2007

The star-formation history and chemodynamical evolution of Blue Compact Dwarf (BCD) galaxies are central issues in dwarf galaxy research. In spite of being old in their vast majority, BCDs resemble in many aspects unevolved low-mass galaxies in the early universe. They are gas-rich (Hi mass fraction of typically > 30%) and metal-deficient (7.1 $\la$ 12+log(O/H) $\la$ 8.3) extragalactic systems, undergoing intense star-forming (SF) activity within an underlying low-surface brightness (LSB) host galaxy.
The Mid-Infrared Properties of Embedded Super Star Clusters in He2-10 and IIZw40
Authors: Sakon I. , Onaka T. , Takahashi H. , Miyata T. , Sako S. , Tajiri Y. Y. , Okamoto Y. K. , Kataza H. , Kaneda H. , Honda M.
Published: April 2007

We observed embedded super-star clusters (SSCs) in blue compact dwarf galaxies (BCDs) IIZw40 and He2-10 with N-band and Q-band imaging and spectroscopy using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on board the 8m Subaru Telescope. Our infrared images of Henize 2–10 resolve the radio knots (knots I-V; Kobulnicky & Johnson 1999) and the N- and Q-band spectra show the strong [NeII] 12.8 μm and the [SIII] 18.71 μm together with relatively weak [SIV] 10.51 μm and [ArIII] 8.99 μm as well as the distinct unidentified infrared (UIR) bands at 8.6, 11.2 and 12.7 μm. We find the typical stellar spectral type of the members in the SSCs is O9 using the CoStar model (Stasinska & Schaerer 1997) and that the ionization environment in the most deeply embedded SSC(POS/#D) is the softest among those SSCs. The UIR bands exhibit a flat distribution over the galaxy and do not show a correlation with the MIR continuum, suggesting that polycyclic aromatic hydrocarbons (PAHs) are not strongly associated with the SSCs. We also find a possible decrease in the UIR 12.7 μm/11.2 μm ratio inside the embedded SSCs, suggesting that smooth-edged large PAHs are dominant (Hony et al. 2001) there. The small UIR to continuum ratio inside the embedded SSCs also suggests that the size distribution of the carbonaceous dust is skewed to the larger ones inside the embedded SSCs. Possible destruction of smaller species by harsh radiation field in the vicinity of massive stars due to the smaller heat capacity and/or the coagulation process that have been undertaken in dense dusty embedded SSCs would explain our results consistently. From the mid-infrared spectroscopy of IIZw40, the UIR bands are detected only in the south-western border of the mid-infrared peaks, suggesting the uneven distribution of PAHs within 4×106yr (Vanzi et al. 1996) after the nuclear starburst triggered in the merging of two small original galaxies.
Chemical evolution and stellar populations in the Sagittarius dwarf Spheroidal Galaxy
Authors: Sbordone L. , Bonifacio P. , Giuffrida G. , Marconi G. , Monaco L. , Zaggia S.
Published: April 2007

The closest neighbour of the Milky Way (MW) the Sagittarius dwarf Spheroidal Galaxy (Sgr dSph) is being tidally destroyed by the interaction with our Galaxy, losing its stellar content along a huge stream clearly detectable within the Halo. This makes the Sgr dSph an ideal laboratory to study at the same time the chemical evolution of dwarf galaxies and their role in building bigger structures such as the MW. Since some years we are studying the stellar populations of the Sgr main body and stream, with particular attention to their detailed chemical composition. We collected detailed abundances (up to 22 elements, O to Eu) for 27 stars in the Sgr dSph main body, 5 in the associated globular cluster Terzan 7, and 12 more in the trailing Sgr tidal arm (UVES@VLT and SARG@TNG data). We are also conducting a large FLAMES@VLT chemical and dynamical analysis aimed at obtaining metallicities, alpha-elements content and radial velocities from automated analysis of the spectra. Finally, we just completed the first large scale photometric and spectroscopic survey of the stellar populations across all the dSph main body extension with VIMOS@VLT, aimed at exploring the variations in stellar populations and at deriving radial velocity memberships for future high resolution spectroscopic analysis. The picture emerging from all these studies portraits a large and extremely complex object, with signs of a long and still unclear evolution. Metallicity varies across three orders of magnitude ([Fe/H] from −3 to 0), CMDs change surprisingly from the core to the outskirts of the galaxy, and the chemical composition of the most metal rich objects show a very characteristic signature, with underabundant alpha elements, deficient Na, underabundant Fe-peak Mn, Co, Ni, Cu and Zn, and strongly enhanced n-capture elements La and Nd. This highly peculiar signature can also be effectively used to recognized stripped populations lost by Sgr in favour of the MW system, as clearly showed by the globular Palomar 12, which shows the same chemical anomalies detected in Sgr dSph.
The San Pedro Mártir Open Cluster Survey: Progress, Techniques, Preliminary Results
Authors: Schuster W. , Michel R. , Dias W. , Tapia-Peralta T. , Vázquez R. , MacFarland J. , Chavarría C. , Santos C. , Moitinho A.
Published: April 2007

A CCD UBVRI survey of northern open clusters is being undertaken at San Pedro Mártir, México, and performed using always the same instrumental setup (telescope, CCD, filters), reduction methods, and system of standards of Landolt (1992). To date more than 300 clusters (mostly unstudied previously) have been observed, and about half the data reduced using aperture-photometry and PSF techniques. Our analysis procedures are being refined by studying in detail a small subset of these clusters. For example, the heavily reddened clusters Be80 and Be95 are being examined in the color-color diagrams: (B-V, U-B) and (B-V, R-I) to better understand the problems of curvature and variable reddening. For clusters for which our U data reaches the F-type stars, such as NGC2192 and NGC7296, techniques are being examined for estimating both the reddening E(B-V) and metallicity [Fe/H] via the use of the (U-B) excess. If the clusters also have “red clump” stars, such as NGC1798 and Do02, these procedures can be iterated between the clump and main sequence stars to establish even better the values of E(B-V) and [Fe/H]. Finally, color-magnitude diagrams, such as (B-V, V) and (V-I, V), are being employed together with the SchmidtKaler (1982) colors and Padova isochrones of Girardi et al. (2000) to obtain distances and ages for these clusters. A java-based computer program is being developed to help in the visualization and analysis of these photometric data. This system is capable of displaying each cluster simultaneously in different color-color and color-magnitude diagrams and has an interactive way to identify a star, or group of stars, in one diagram and to see were it falls in the other diagrams, facilitating the elimination of field stars and the apperception of cluster features. This program is capable of displaying up to 16 different diagrams for one cluster and processing up to 20 clusters at the same time. Our aims are the following: (1) a common UBVRI photometric scale for open clusters, (2) an atlas of color-color and color-magnitude diagrams for open clusters, (3) a homogeneous set of cluster reddenings, distances, and ages, (4) an increased number of old and distant open clusters, and (5) a selection of interesting clusters for further study.
GALEX Ultraviolet Observations of Globular Clusters in Nearby Galaxies
Authors: Rey Soo-Chang , Sohn Sangmo T. , Rich R. Michael , Yoon Suk-Jin , Chung Chul , Yi Sukyoung K. , Lee Young-Wook
Published: April 2007

The hot He-burning horizontal-branch (HB) stars and their progeny are most likely dominant ultraviolet (UV) sources in the old stellar population systems such as globular clusters (GCs). Integrated FUV flux can be an age indicator of GCs and allow us to investigate age distributions of GCs within a given galaxy or between galaxies. The unprecedented set of UV photometry for M31 by Galaxy Evolution Explorer (GALEX), coupled with most recent detailed population models enable to study detailed global UV properties of M31 GCs.
Star Forming Galaxies and AGN Hosts: The Seagull Wings
Authors: Stasińska Grazyna , Fernandes Roberto Cid , Mateus Abílio , Sodré Laerte , Asari Natalia V.
Published: April 2007

Using photoionization models applied to the data from the Sloan Digital Sky Survey (SDSS) we propose a physically motivated dividing line in the [OIII]/Hβ vs [NII]/Hα (BPT) diagram between normal star forming (NSF) galaxies and AGN hosts. We also propose a new diagnostic diagram which can be used for optical spectra of galaxies with redshifts up to z= 1.3.
Statistical Studies on the Visible and Hidden Star Formation in the Universe
Authors: Takeuchi T. T. , Buat V. , Burgarella D. , Iglesias-Páramo J.
Published: April 2007

We select far-infrared (60 μm) and far-ultraviolet (1530Å) samples of nearby galaxies. We derived distributions of the bolometric luminosity of young stars in both samples: they are found to be consistent with each other for galaxies of intermediate luminosities but some differences are found for high (>5 × 1010L⊙) luminosities. The ratio of the total IR luminosity to the FUV one is found to increase with the bolometric luminosity in a similar way for both samples up to 5 × 1010L⊙. Brighter galaxies are found to have a different behavior according to their selection: the LTIR/LFUV ratio of the FUV selected galaxies brighter than 5 × 1010L⊙ reaches a plateau whereas LTIR/LFUV continues to increase with the luminosity of bright galaxies selected in FIR. The volume averaged specific star formation rate (SFR per unit galaxy stellar mass, SSFR) is found to decrease toward massive galaxies within each selection. The SSFR is found larger than that measured for optical and NIR selected sample for the whole mass range for the FIR selection and for masses larger than 1010M⊙ for the FUV selection. Luminous and massive galaxies selected in FIR appear as active as galaxies with similar characteristics detected at z ~ 0.7. Details are presented in Buat et al. (2006).
Kinematics of the Ionized Gas in Dwarf Irregular Galaxies
Authors: Valdez-Gutiérrez Margarita , Rosado Margarita
Published: April 2007

Some preliminary results focused on the kinematics and dynamics of the ionized gas in the Local Group dwarf irregular galaxy IC10 are presented.
First consistent Lyα profile and UV spectral modeling of z ~ 3 LGBs with a 3D radiative transfer code
Authors: Verhamme A. , Schaerer D. , Atek H.
Published: April 2007

We developped a 3D Monte Carlo Lyα radiation transfer code to understand the diversity of Lyα line profiles observed in star forming galaxies and related objects (Verhamme et al. 2006). Our code allows for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distributions, and arbitrary velocity fields and UV photon sources.Here we present results from the first modelling of the Lyα line and of the UV spectrum with our code of a sample of z ~ 3 Lyman break galaxies observed by Steidel and collaborators (Pettini et al. 2002) and taken from the FORS Deep Field (Tapken et al. 2006). A simple model of an expanding neutral shell surrounding a starburst region can reproduce the whole variety of spectra ranging from double-peaked profiles to asymetric emission lines, P-Cygni profiles or broad absorption. The main determining parameters are the outflow velocity and the dust content. Other parameters such as the hydrogen column density, the intrinsic Lyα emission and hence SFR, and the intrinsic Lyα line widths can be determined consistently taking all radiation transfer effects into account.
When do early-type galaxies form?
Authors: Abraham Roberto G. , McCarthy Patrick J. , Mentuch Erin , Glazebrook Karl , Nair Preethi , Gauthier Jean-René , Savaglio Sandra , Crampton David , Juneau Stephanie , Murowinski Richard , Le Borgne Damien , Carlberg R. G. , Jørgensen Inger , Roth Kathy , Chen Hsiao-Wen , Marzke Ronald O.
Published: April 2007

We have used the Hubble Space Telescope's Advanced Camera for Surveys to measure the mass density function of morphologically-selected early-type galaxies in the Gemini Deep Deep Survey fields, over the redshift range 0.9 < z < 1.6. Our imaging data set covers four well-separated sight-lines, and is roughly intermediate (in terms of both depth and area) between the GOODS/GEMS imaging data, and the images obtained in the Hubble Deep Field campaigns. Our images contain 144 galaxies with ultra-deep spectroscopy, and they have been analyzed using a new purpose-written morphological analysis code which improves the reliability of morphological classifications by adopting a ‘quasi-petrosian’ image thresholding technique. We find that at z = 1 approximately 70% of the stars in massive galaxies reside in early-type systems. This fraction is remarkably similar to that seen in the local Universe. However, we detect very rapid evolution in this fraction over the range 1.0 < z < 1.6, suggesting that in this epoch the strong color-morphology relationship seen in the nearby Universe is beginning to fall into place.
The Cosmic Evolution of Early-type Galaxies
Authors: Cimatti Andrea
Published: April 2007

The latest observational results on the formation and evolution of early-type galaxies are reviewed by focusing on the issues of mass assembly and downsizing scenario.
CATS: CfAO Treasury Survey of distant galaxies, supernovae, and AGN's
Authors: Koo David C. , Melbourne Jason , Max Claire , Metevier Anne , Ammons Mark , Larkin James E. , Barczys Matthew , Wright Shelley A. , Steinbring Eric
Published: April 2007

The NSF Science and Technology Center for Adaptive Optics (CfAO) is supporting a major scientific legacy project called the CfAO Treasury Survey (CATS). CATS is obtaining near-infrared AO data in deep HST survey fields, such as GEMS, GOODS-N, & EGS. Besides summarizing the main objectives of CATS, we highlight some recent imaging work on the study of distant field galaxies, AGNs, and a redshift z = 1.32 supernova. CATS plans the first data release to the community in early 2007 (check http://www.astro.ucla.edu/~irlab/cats/index.shtml for more details on CATS and latest updates).
First Galaxies and AGNs
Authors: Walter Fabian
Published: April 2007

I will discuss the search for galaxies and QSOs at the highest redshifts, out to the Epoch of Reionization. Observations in the submillimeter play a fundamental role in such searches, in particular once ALMA will become operational. I will focus on the properties of the molecular gas (the phase of the ISM out of which stars form) in the earliest systems as derived through observations in the millimetre and radio regime. These observations allow us to measure the reservoir of molecular gas and to constrain the physical properties and excitation of the gas. Resolved imaging of the host galaxies also allows us to derive first dynamical masses for these objects. Such mass determinations are critical to determine whether there is a possible evolution of the famous MBH–σbulgerelation with redshift or not. Recent measurements in the QSO redshift record holder J1148+5251 (z= 6.42) provide evidence that the black hole in this system assembled before the stellar bulge.
Luminosity Dependent Evolution of Lyman Break Galaxies from redshift 5 to 3
Authors: Iwata I , Ohta K. , Tamura N. , Akiyama M. , Aoki K. , Ando M. , Kiuchi G. , Sawicki M.
Published: April 2007

The development of large ground-based telescopes and sensitive large format detectors, as well as the develepment of various techniques for the selection of high-z galaxies enabled us to construct large samples of galaxies in the early universe, as reported in the many contributions in this proceedings. The next major step for the comprehensive understanding of the galaxy evolution would be to explore the relationship of galaxies selected with different criteria at different epochs and find links between them. In this contribution we present the properties of Lyman break galaxies (LBGs) at z ~ 5 obtained by deep and wide blank field surveys, and through the comparison with samples at lower redshift ranges we discuss the evolution of star-forming galaxies in the early universe.
Cosmological formation of disc galaxies
Authors: Portinari Laura , Sommer–Larsen Jesper
Published: April 2007

We review the current status of cosmological simulations of the formation and evolution of disc galaxies, discussing in particular the Tully-Fisher relation and its redshift evolution.
Massive and Evolved Galaxies at z ≥ 5
Authors: Wiklind T. , Mobasher B. , Dickinson M. , Ferguson H. , Giavalisco M. , Grogin N. , Panagia N.
Published: April 2007

We search for massive and evolved galaxies at z ≥ 5 in the Great Observatories Origins Deep Survey (GOODS) southern field. Combining HST ACS, VLT ISAAC and Spitzer IRAC broad–band photometric data, we develop a color selection technique to identify candidates for being evolved galaxies at high redshifts. The color selection is primarily based on locating the Balmer–break using the K- and 3.6 μm bands. Stellar population synthesis models are fitted to the SEDs of these galaxies to identify the final sample. We find 11 candidates with photometric redshifts in the range 4.9 < z < 5.6, dominated by an old stellar population, with ages 0.2-1.0 Gyr, and stellar masses in the range (0.7 − 5) × 1011 M⊙. Most of the candidates have modest amounts of internal dust extinction. The majority of the stars in these galaxies were formed at z>9 and the current star formation activity is a few percent of the inferred initial star formation rate.
Clumpy Galaxies in the Early Universe
Authors: Elmegreen Debra Meloy
Published: April 2007

Clumpy galaxies are prominent in the early Universe. We present morphological and photometric properties of a wide range of galaxy types and their star-forming clumps in the Hubble Ultra Deep Field. Sizes, scale lengths, and scale heights suggest that galaxies grow by a factor of 2 fromz= 4 to the present, and that thick disks are present in the early Universe. The largest clumps of star formation are 107–109M⊙in different galaxies, much more massive than large star-forming complexes in local galaxies. Dissolved clumps may account for both the exponential disks and the early thick disks of spirals and proto-spiral galaxies.
Galaxy Mergers and Interactions at High Redshift
Authors: Conselice Christopher J.
Published: April 2007

In this review we discuss the evidence for galaxy interactions and mergers in the distant universe and the role of mergers in forming galaxies. Observations show that the fraction of massive (M>M*) galaxies involved in major mergers is roughly 5–10% at z ~ 1. The merger fraction however increases steeply for the most massive galaxies up to z ~ 3, where the merger fraction is 50± 20%. Using N-body models of the galaxy merger process at a variety of merger conditions, merger mass ratios, and viewing angles this merger fraction can be converted into a merger rate, and mass accretion rate due to mergers. A simple integration of the merger rate shows that a typical massive galaxy at z ~ 3 will undergo 4–5 major mergers between z ~ 3 and z ~ 0, with most of this activity, and resulting mass assembly, occurring at z>1.5.
The Evolution of Disk Galaxy Scaling Relations Since Redshift z = 1
Authors: Böhm Asmus , Ziegler Bodo L.
Published: April 2007

Based on VLT/FORS spectroscopy and HST/ACS imaging, we have constructed a sample of 125 field spiral galaxies that cover redshifts up to z = 1. By deriving the galaxies' luminosities, disk sizes, maximum rotation velocities, stellar masses, total masses, gas-phase metallicities etc., we are able to study the evolution of fundamental scaling relations like the Tully–Fisher relation as a function of cosmic time. While the evolution of most of the galaxies' fundamental parameters is in compliance with a hierarchical structure growth, the results from stellar population modelling favour a down-sizing scenario in the sense that the average stellar ages in high-mass spirals are older than in low-mass spirals.
Are strong z ≃ 0.5 MgII absorbers the signature of super-winds?
Authors: Bouché N. , Murphy M. , Péroux C. , Csabai I. , Wild V.
Published: April 2007

BACKGROUND: In the process of galaxy formation, super-nova driven feedback from low-mass galaxies is the process that most readily account for the galaxy mass-metallicity relation and for the shallower galaxy luminosity function (LF) compared to the halo mass function. Absorption-selected galaxies are prime candidates for the sites of starburst activity as (1) they probe the gaseous halos of galaxies up to ~50 kpc (Steidel 1995), and (2) galaxies on the faint end of the LF are likely dominating the statistics. Galaxies selected via their MgII λ2796/2803 doublet absorption against background QSOs are especially well suited as Mg is produced by type II supernova.

GOAL: Our project was to constrain the physical models of the gaseous halos by measuring the dark matter halo-mass (Mh) of the MgII host-galaxies statistically, i.e. without identifying spectroscopically the host-galaxy.

METHOD: We have used the cross-correlation w(rθ) (over co-moving scales rθ:0.05–13h−1Mpc) between our sample of 1800 z ≃ 0.5 MgII absorbers with equivalent w width W2796r−0.3 Å, and 250,000 Luminous Red Galaxies (LRGs), both selected from SDSS/DR3. The cross-correlation relies on the LRG photometric redshifts, but is not affected from contaminants such as stars or foreground and background galaxies as shown theoretically in Bouché et al. 2005 and empirically in Bouché et al. 2006.

RESULTS: From the cross-correlation analysis, we found (Bouché et al. 2006) (i) that the absorber host-halo mean mass is 〈 log Mh (M⊙)〉 = 11.94 ±0.31(stat)+0.24−0.25(sys), i.e. about 1/2 L*, and (ii) an anti-correlation between halo mass Mh and equivalent width W2796r.

INTERPRETATION: One SDSS MgII absorber (system) is made of several sub-components or clouds and the stronger the equivalent with of the absorber, the more clouds per system spread over a larger velocity range (Δv). This follows since each sub-component has a velocity width of ~ 5 kms s−1 (Churchill 1997). As result, the equivalent width W2796r is a measure of velocity width (Δv) as demonstrated by Ellison 2006. Together with our SDSS results, these relations imply a mass–velocity Mh–Δv anti-correlation. If the clouds in the host-halos were virialized, velocity and mass would have been correlated.

CONCLUSION: Therefore, our Mh–Δv anti-correlation shows that the clouds are not virialized in the gaseous halos of the hosts. This conclusion is best understood in the context of starburst driven outflows where the velocity Δv is related to bulk motion. This opens the possibility to study M82-analogs up to z ~ 2.0 using the MgII selection.
Evolution of the Mass-to-light Ratio of Galaxies to z~ 0.25
Authors: Catinella B. , Haynes M. P. , Gardner J. P. , Connolly A. J. , Giovanelli R.
Published: April 2007

We present the first results of a targeted survey carried out with the 305m Arecibo radiotelescope to detect HI-line emission from disk galaxies at redshift z > 0.16. We are using this sample to study the evolution of the zero point of the Tully-Fisher relation (TFR) for galaxies at intermediate redshifts. Compared to optical widths, HI measurements sample a larger fraction of the disks, where the rotation curves are typically flat, and are not affected by slit smearing and misalignment or by aperture effects. Thus, in contrast to studies based on optical spectroscopy, this dataset allows for a direct comparison with the local TFR that is technique independent.
The role of the gas in the bar instability. A cosmological approach
Authors: Curir Anna , Mazzei Paola , Murante Giuseppe
Published: April 2007

The growth and the evolution of the bar instability in stellar-gaseous disks embedded in a dark matter halo evolving in a cosmological framework is explored. We point out the impact of different gas fractions on the bar formation, inside disks of different disk-to-halo mass ratio.
The Nature of Near Ultraviolet Sources in the GOODS Fields
Authors: de Mello D. F. , Dahlen T. , Gardner Jonathan P.
Published: April 2007

We present the latest results of the survey searching for the nature of UV-selected galaxies in the Great Observatories Origins Deep Survey fields. By searching for UV-bright galaxies at intermediate redshifts (z ~ 1) we aim at understanding the nature of star-forming galaxies and their counterparts at higher-z, the so-called Lyman Break Galaxies.
The VIMOS VLT Deep Survey: A census of active and passive galaxies to redshift 1.3
Authors: Vergani D.
Published: April 2007

We are studying how stellar masses assemble through cosmic time since the Universe had only 30% of its present age. We are conducting a census of galaxies which covers the end of the most active star-forming phase, using a mass-limited sample of approximately 5,000 objects selected from the VIMOS VLT Deep Survey (VVDS) in the redshift range 0.45 < z < 1.3. With a criterion based on the direct spectral measurement of the 4000Å Balmer break, Dn(4000), we have classified our sample in spectroscopically early and late-type galaxies. The trends existing between stellar mass, spectroscopic classification, and star formation activity are clearly shown in our analysis.
Cosmic Evolution of Quasar Host Galaxies
Authors: Floyd D. , Kukula M. , Dunlop J. , McLure R. , O'Dea C. , Baum S.
Published: April 2007

Using HST WFPC2 and NICMOS observations, and our 2D image weighting and modelling technique (Floyd et al. 2004), we have reliably disentangled host from nucleus for nine optically matched radio-loud quasars (RLQ) and nine radio-quiet quasars (RQQ) at z = 1&2, in two bands spanning the 4000Å break. The resulting galaxy colours provide the first unbiased estimates of galaxy mass for a statistical sample of quasars at high redshift, and indicates a difference in the evolution of radio-loud and radio-quiet objects.
Morphology of z ~ 1 galaxies from deep K-band AO imaging
Authors: Huertas-Company Marc , Rouan Daniel , Soucail Geneviève , Le Fèvre Olivier , Tasca Lidia
Published: April 2007

We present the results of observations of distant galaxies (z ~ 0.8) at high spatial resolution (~0.1"). We observed 7 fields of 1' × 1' with the NACO Adaptive Optics system (VLT) in Ks (2.2μm) band with typical V ~ 14 guide stars and 3h integration time per field. Observed fields are selected within the COSMOS survey area. We analyze the morphologies by means of B/D (Bulge/Disk) decomposition with GIM2D and CAS (Concentration-Asymmetry) estimators for 79 galaxies with magnitudes between Ks = 17 − 23 and classify them in three main morphological types (Late Type, Early Type and Irregulars). We obtain for the first time an estimate of the distribution of galaxy types at redshift z ~ 1 as measured from the near infrared at high spatial resolution.
Photometry and Spectroscopy of i-drop Galaxies: Possible Detection of A Proto-cluster at z=6
Authors: Ota Kazuaki
Published: April 2007

We discovered 30 candidate galaxies are clustering in a small ~200 Mpc2 region at z = 6 with 5σ local density excess in a wide 876 arcmin2 field. Four of them were spectroscopically identified as z = 5.9–6.0 Lyα emitters (~34 Mpc in line-of-sight). This structure is comparable to z = 4.8 and 5.7 galaxy proto-clusters previously found. Since the other candidates are likely to be real galaxies due to low sample contamination, the overdensity can be a z~6 proto-cluster.
The evolution of the mass-metallicity relation up to z≈0.9 from the VIMOS/VLT Deep Survey
Authors: Lamareille F. , Contini T. , Charlot S. , Brinchmann J. ,   the VVDS team
Published: April 2007

We present the first results derived from the spectrophotometric properties of the Vimos VLT Deep Survey (VVDS) first epoch data. We have measured the spectral features (emission/absorption lines, 4000Å break) of a sample a ≈8000 galaxies taken from the VVDS deep 02h and CDFS fields using the platefit VVDS pipeline. We first selected a sub-sample of star-forming galaxies, which were distinguished from narrow-line AGNs by standard and blue diagnostic diagrams. Then the gas-phase oxygen abundances have been derived by fitting all available emission lines towards photo-ionization models. Finally the masses have been derived by fitting all photometric points together with significant spectral features to a library of stellar population models with complex star formation histories. The mass-metallicity relation that we find at low redshifts is in good agreement with previsous studies performed in the local Universe. We find moreover a significant evolution of the mass-metallicity relation with the redshift, the galaxies having on average less metals at a given mass when the redshift increases. We also find a flattening of the mass-metallicity relation up to z ~ 1.
Blue Early-type Galaxies in the GOODS Fields
Authors: Gyoon Lee Myung , Hyeop Lee Joon , Seong Hwang Ho
Published: April 2007

We present a study of the nature of the blue early-type galaxies found in the HST/ACS images of the GOODS north and south fields.
The primordial CH molecule as a possible probe for the first structures formation epoch
Authors: Campos J.C. , Saucedo Morales J.C. , Lipovka A.A. , Nunes-Lopez R.
Published: April 2007

The role of primordial CH molecules in the first structures formation epoch is considered. We discuss the plausibility of observing protostructures in the Dark Age epoch of the Universe by studying the rotational structure of the CH molecule. It is stressed that considerable abundances of this molecule could be formed for different Inhomogeneous BBN models, which could lead to observable spectral-spatial fluctuations in the CMBR spectrum. The calculation is carried out for the Lambda-CDM cosmology and for typical first structures physical conditions. The chemical evolution of the structures is followed numerically, and the optical depth for the most important ground rotational transitions of the CH molecule are proposed. It is shown that under reasonable conditions the primordial CH molecule can be observed with mm-telescopes under construction.
The stellar mass-metallicity relations of galaxies from high-z to the local
Authors: Liang Y. C. , Hammer F. , Deng L. C.
Published: April 2007

The stellar mass-metallicity relations of star-forming galaxies at intermediate-z (0.4<z<1) and high-z (z≥2) are compared with the local SDSS galaxies. It shows obvious evolutionary effect, i.e., at a given stellar mass, the intermediate-z galaxies show about 0.3 dex lower metallicity, and the high-z galaxies show about 0.56 dex more metal-deficient than the local ones. These distant galaxies will produce these important parts of their metals during the consequent evolutionary process. A close-box model can explain this evolutionary process generally.
COMBO-17+4: An Optical-NIR Survey for Galaxies out to z=2
Authors: Nicol M-H. , Meisenheimer K. , Tapken C. , Wolf C.
Published: April 2007

Classifying Object by Medium-Band Observations in 17 filters (COMBO-17) has already produced a very accurate picture of galaxy evolution since z~1 based on 25000 galaxies in 17 medium optical bands. We now extend the range of reliable multi-color redshifts with COMBO-17+4, a deep optical-NIR survey which will combine the existing optical data set of COMBO-17 with near infrared observation in three medium bands: Y(λ/Δλ = 1040/80nm), J1(1190/130nm) and J2(1320/130nm) and one broad band H(1650/300nm). The NIR bands extend the photometric redshift range to z~2.1. COMBO 17+4 will provide the first large sample of galaxies (>5000) at 1<z<2 with a redshifts accuracy of Δz<0.03(1+z). Three fields are observed: Abell 901, Abell 226 and the COMBO 11h-field, for a total coverage of 0.77□2 of the sky. Each COMBO 17+4 field measures 31 × 30 sqarcmin. The NIR bands are observed with the Omega2000 camera at Calar Alto Observatory in Spain.

The scientific goals for this study are multiple. COMBO-17+4 will enable us to establish the luminosity function for the red sequence and blue galaxies in the redshift range 1<z<2. Also it will be possible to determine the formation history at z=2 by analyzing the width of the red sequence galaxies. Moreover this survey will provide several thousand of individual galaxy masses (with an accuracy <30%) obtained with Spectral Energy Distribution (SED) template fitting. Once the masses are obtained the mass function will provide a useful tool to test the hierarchical model of evolution of galaxies by checking whether the massive red sequence galaxies (logM>10.5) are already in place at z>1.5 (9Gyr).

We present first results from the full 21 bands photometry in half of the Abell 901 field. It allows us to study not only z>1 galaxies but also the stellar content of several hundred cluster galaxies.