bluuebunny/crossref_metadata_2025 huggingface dataset:
Constraining Dark Matter-Dark Energy Interaction with Gas Mass Fraction in Galaxy Clusters
Authors: Gonçalves R. S. , Alcaniz J. S. , Dev A. , Jain D.
Published: October 2010

The recent observational evidence for the current cosmic acceleration have stimulated renewed interest in alternative cosmologies, such as scenarios with interaction in the dark sector (dark matter and dark energy). In general, such models contain an unknown negative-pressure dark component coupled with the pressureless dark matter and/or with the baryons that results in an evolution for the Universe rather different from the one predicted by the standard ΛCDM model. In this work we test the observational viability of such scenarios by using the most recent galaxy cluster gas mass fraction versus redshift data (42 X-ray luminous, dynamically relaxed galaxy clusters spanning the redshift range 0.063 < z < 1.063), Allen et al. (2008), to place bounds on the parameter ε that characterizes the dark matter/dark energy coupling. The resulting are consistent with, and typically as constraining as, those derived from other cosmological data. Although a time-independent cosmological constant (ΛCDM model) is a good fit to these galaxy cluster data, an interacting energy component cannot yet be ruled out.
Detecting individual gravity modes in the Sun: Chimera or reality?
Authors: García Rafael A.
Published: October 2010

Over the past 15 years, our knowledge of the interior of the Sun has tremendously progressed by the use of helioseismic measurements. However, to go further in our understanding of the solar core, we need to measure gravity (g) modes. Thanks to the high quality of the Doppler-velocity signal measured by GOLF/SoHO, it has been possible to unveil the signature of the asymptotic properties of the solar g modes, thus obtaining a hint of the rotation rate in the core (García et al. 2007, 2008a). However, the quest for the detection of individual g modes is not yet over. In this work, we apply the latest theoretical developments to guide our research using GOLF velocity time series. In contrary to what was thought till now, we are maybe starting to identify individual low-frequency g modes. . .
Magnetic structure of sunspot under the photosphere
Authors: Kirichek Elena A. , Solov'ev Alexandr A.
Published: October 2010

In recent years, the local helioseismology has become a highly effective tool for investigating subphotospheric layers of the Sun, which can yield fairly detailed distributions of the subphotospheric temperatures and large-scale plasma flows based on the spectra of the oscillations observed at the photospheric layers and the observed peculiarities of propagation of magnetoacoustic waves in this medium (Zhao et al. (2001), Kosovichev (2006)). Unfortunately, the effects of temperature and the magnetic field on the wave propagation speed have not yet been separated Kosovichev (2006), so that the structure of the sunspot magnetic field in deep layers, beneath the photosphere, remains a subject of purely theoretical analysis. In his analysis of some theoretical models of the subphotospheric layers of sunspots based on recent helioseismological data, Kosovichev (2006) concluded that Parker's (“spaghetti”) cluster model Parker (1979) is most appropriate. In this model, the magnetic flux in the sunspot umbra is concentrated into separate, strongly compressed, vertical magnetic flux tubes that are interspaced with plasma that is almost free of magnetic field; the plasma can move between these tubes.
Differential Rotation of the Sun from helioseismology and magnetic field study.
Authors: Gavryuseva Elena , Höfner Susanne
Published: October 2010

Differential rotational rate of the large scale magnetic field and its temporal dependence has been evidenced at different latitudes through activity cycles 21-23. Rotational rate of the magnetic field at the latitudes above 55 degrees doesn't getting slower. Torsional waves with 11-year period are clearly seen in the magnetic field rotation. Rotation is slower where and when the magnetic field is getting stronger.

The time of the magnetic field emergence to the photosphere was estimated.

It was revealed the existence of quasi-stable over 30 years exceptionally regular and symmetric in the both hemispherest longitudinal structure. This structure is originated from the tachocline zone rotating like a rigid body with the rotation rate corresponding to the rotation in the photosphere on the 55-60 degrees of the helio-latitudes.
Asteroseismology of massive stars with the MOST satellite
Authors: Moffat Anthony F. J. ,   The MOST Team
Published: October 2010

Since 2003 the MOST (Microvariability and Oscillations of STars) microsatellite has obtained typically a month of non-stop, minute-of-time resolution, high-precision, single-broadband optical photometry for each of a significant number of Galactic OB and WR stars. Numerous p- and g-modes were clearly detected in several OB stars, including discovery of g-modes for the first time in a blue supergiant (Saio et al. 2006). True rotation periods were found for some SPBe pulsators (Cameron et al. 2008). Many O stars are remarkably quiet. Five presumably single WR stars have been observed so far, each interesting in its own way. In particular, the cool WR stars WR123 (WN8) and WR103 (WC9d) both show mostly short-lived, multimode oscillations with most of the Fourier power occurring on a day or longer timescale (Moffat et al. 2008a). WR123 also revealed a fairly stable 10-hour periodicity (Lefèvre et al. 2005). All of these oscillations probably arise in the stellar cores. WR111 (WC5) shows no (coherent) oscillations above the detection limit of 0.05 mmag in the 10-minute period range predicted for strange-mode pulsations at a level of 2 mmag (Moffat et al. 2008b). WR110 (WN5-6 and a stronger-than-average X-ray source) and WR124 (WN8h, i.e. in contrast with the previously observed, hydrogen-free WR123 of otherwise similar subtype), both strongly variable with MOST, are currently being analyzed. The next target just observed (late-June to early Aug 2009) is the 30-day eclipsing binary CV Ser = WR113 (WC8d + O8-9IV). Besides stellar oscillations, we will also search for orbital-phase dependent, stochastic variability in CV Ser as wind clumps in the WR component's dense wind pass in front of the O-star.
JD14 – Examining the PDR-molecular cloud interface at mm and IR wavelengths
Authors: Simon R. , Ossenkopf V. , Röllig M.
Published: October 2010

Much progress has been made in recent years towards a better understanding of the physical and chemical processes in Photo-dissociation/Photon-dominated Regions (PDRs), both observationally and in terms of detailed physical and chemical modelling. This article highlights some of the problems and new opportunities observers and modellers are facing.
Atomic carbon in an infrared dark cloud
Authors: Ossenkopf Volker , Ormel Chris W. , Simon Robert , Sun Kefeng , Stutzki Jürgen
Published: October 2010

Infrared dark clouds (IRDCs) are potential sites of massive star formation, dark in the near-infrared, but in many cases already with indications of active star-formation from far-infrared and submm observations. They are an ideal test bed to study the role of internal and external heating on the structure of the molecular cloud material.
The Phase Structure of the ISM in Galaxies
Authors: Wolfire Mark G.
Published: October 2010

Diffuse gas in the Galaxy is observed to exist as cold (T ~ 100 K) neutral atomic gas (CNM) and warm neutral atomic (T ~ 8000 K) gas (WNM). In addition to these “thermal” phases, gas can also exist as warm (T ~ 8000 K) ionized gas, cold (T ~ 10 K) molecular gas and in warm (T ~ 100 - 500 K) interface regions or Photodissociation Regions (PDRs) on the surfaces of molecular clouds. The same chemical and thermal processes that dominate in the PDRs associated with molecular clouds are also at work in the diffuse neutral gas. Two additional “phases” are gas associated with GMCs that has H2 but no or little CO, and short lived or transient phases such as shocks, shears, and turbulence. I will first review the different gas phases in the Galaxy, their physical conditions and their dominant cooling lines. I will also discuss the observations and theoretical modeling in support of turbulence versus thermal instability as the driving force in producing the “thermal” gas phase distributions. Rough estimates for the distribution of phases in the Galaxy and the origin of the dominant emission lines has been conducted by previous telescopes (e.g., COBE, BICE) but with low velocity and low spectral resolution. The distribution and mass of the various gas phases is important for sorting out the role of SN in setting ISM pressures and in driving ISM turbulence. In addition, understanding the Galactic phase distribution is important in interpreting observations of extragalactic systems in which beams encompass several emission components. I will review the potential for future observations by e.g., STO, SOFIA, and Herschel to detect and separate phases in Galactic and extragalactic systems.
Diagnosing the ISM in star-forming regions
Authors: Baan Willem A. , Loenen Edo , Spaans Marco
Published: October 2010

A report on studies using the observed line ratios of high-density molecular tracers to diagnose the physics and chemistry of the ISM in star-formation environments.
Chemical tracers of dense gas in extragalactic environments
Authors: Viti Serena , Bayet Estelle
Published: October 2010

Within the context of ALMA (and future missions such as SPICA) we present some recent observational and theoretical work on molecular line emissions from extragalactic environments.
AKARI Far-Infrared View of Nearby Galaxies
Authors: Kaneda H. , Suzuki T. , Onaka T. , Takase I. , Yamagishi M. , Ishihara D. , Sakon I.
Published: October 2010

We have observed 57 nearby galaxies in the far-infrared with the Far-Infrared Surveyor on AKARI to study the properties of dust in various environments.
The interplay of dense gas and stars in M33
Authors: Kramer Carsten , Buchbender Christof , Quintana-Lacaci Guillermo , Braine Jonathan , Gratier Pierre , Rosolowsky Erik
Published: October 2010

We are studying the interplay of star formation and its ’fuel’, the molecular gas (diffuse and dense) at selected positions along the major axis of M33. We have observed the ground-state transitions of HCN, HCO+, and 13CO using the IRAM 30m telescope. These data will complement existing CO, HI, Spitzer, and radio continuum maps. Furthermore, these data will be complemented by far-infrared maps of [CII], H2O, [OI], [NII], and the dust continuum taken with Herschel in the open time key project HERM33ES.
The radio-infrared correlation in galaxies
Authors: Tabatabaei F. S. , Beck R. , Berkhuijsen E.
Published: October 2010

The radio–infrared correlation holds within galaxies down to scales of about 50 pc (Hughes et al. 2006). It was explained as a direct and linear relationship between star formation and IR emission. However, one fact making the IR-star formation linkage less obvious is that the IR emission consists of at least two emission components, cold dust and warm dust. The cold dust emission may not be directly linked to the young stellar population. Furthermore, understanding the origin of the radio–IR correlation requires to discriminate between the two main components of the radio continuum emission, free-free and synchrotron emission. Although cosmic ray electrons originates also from the star forming regions (supernovae remnants; final episodes of massive stars), the synchrotron–IR correlation may not be as tight as thermal–IR correlation locally, as a result of convection and diffusion of the cosmic ray electrons from their place of birth. The magnetic field distribution may further modify the correlation.
Molecular lines studies at redshift greater than 1
Authors: Combes Françoise
Published: October 2010

Observations of CO molecules in the millimetrer domain at high redshift (larger than 1), have provided interesting informations about star formation efficiency, and its evolution with redshift. Due to the difficulty of the detections, selection effects are important. The detection if often due to gravitational amplification. Objects selected by their (far)infrared flux, are in general associated to ULIRGS, mergers with starburst in the nuclear regions. Quasars have been selected as powerful optical sources, and have been found to be associated to starbursts, rich in gas. The gas fraction appears to be much higher at redshift greater than 1. Quasars allow to probe the end of the reionisation period, and the relation between bulge and black hole mass. However these selection bias could have led us to miss some gaseous galaxies, with low-efficiency of star formation, such as the more quiescent objects selected by their BzK colors at z = 1.5 or 2.
Vibrationally Excited HC3N in NGC 4418
Authors: Costagliola F. , Aalto S.
Published: October 2010

Luminous infrared galaxies (LIRGs) emit most of their radiation in the infrared region of the spectrum in the form of dust thermal continuum, with typical luminosities of LIR > 1010 L⊙. The central power source responsible for the total energy output is deeply buried in the dusty central regions of these objects and its origin still unclear. Recent studies by Spoon et al. (2007) and Aalto et al. (2007) suggest that some LIRGs might represent early obscured stages of active galaxies, either AGNs or starbursts, and thus play a fundamental role in galaxy formation and evolution.
Detecting the first quasars with ALMA
Authors: Schleicher Dominik R. G. , Spaans Marco , Klessen Ralf S.
Published: October 2010

We show that ALMA is the first telescope that can probe the (dust) obscured central region of quasars at z > 5 with a maximum resolution of ~ 30 pc employing the 18 km baseline.
Zeeman Splitting in the Diffuse ISM
Authors: Heiles Carl
Published: October 2010

Many Zeeman-spitting measurements in the diffuse Galactic Interstellar Medium have been made of the 21-cm line in both absorption and emission. Typical field strength is about 6 μG, with enhancement in shocked regions; the magnetic, turbulent, and cosmic-ray pressures are comparable and considerably larger than the thermal gas pressure. For PhotoDissociation Regions, Carbon recombination lines show intriguing results for single-dish measurements. OH Megamasers in Ultra-Luminous Infrared Galaxies show easily detectable fields whose strength ranges up to at least 20 mG. Upper limits for several damped Ly-α systems range down to a few μG. The z=0.692 system against 3C286 was reported in the literature to have a large field strength, but this result is wrong.
Turbulent diffusion and galactic magnetism
Authors: Brandenburg Axel , Sordo Fabio Del
Published: October 2010

Using the test-field method for nearly irrotational turbulence driven by spherical expansion waves it is shown that the turbulent magnetic diffusivity increases with magnetic Reynolds numbers. Its value levels off at several times the rms velocity of the turbulence multiplied by the typical radius of the expansion waves. This result is discussed in the context of the galactic mean-field dynamo.
2D and 3D turbulent magnetic reconnection
Authors: Lazarian A. , Kowal G. , Vishniac E. , Kulpa-Dubel K. , Otmianowska-Mazur K.
Published: October 2010

A magnetic field embedded in a perfectly conducting fluid preserves its topology for all times. Although ionized astrophysical objects, like stars and galactic disks, are almost perfectly conducting, they show indications of changes in topology, magnetic reconnection, on dynamical time scales. Reconnection can be observed directly in the solar corona, but can also be inferred from the existence of large scale dynamo activity inside stellar interiors. Solar flares and gamma ray busts are usually associated with magnetic reconnection. Previous work has concentrated on showing how reconnection can be rapid in plasmas with very small collision rates. Here we present numerical evidence, based on three dimensional simulations, that reconnection in a turbulent fluid occurs at a speed comparable to the rms velocity of the turbulence, regardless of the value of the resistivity. In particular, this is true for turbulent pressures much weaker than the magnetic field pressure so that the magnetic field lines are only slightly bent by the turbulence. These results are consistent with the proposal by Lazarian & Vishniac (1999) that reconnection is controlled by the stochastic diffusion of magnetic field lines, which produces a broad outflow of plasma from the reconnection zone. This work implies that reconnection in a turbulent fluid typically takes place in approximately a single eddy turnover time, with broad implications for dynamo activity and particle acceleration throughout the universe. In contrast, the reconnection in 2D configurations in the presence of turbulence depends on resistivity, i.e. is slow.
From Magnetized Cores to Protoplanetary Disks
Authors: Lizano Susana , Shu Frank H.
Published: October 2010

We highlight several recent theoretical results that show how magnetic fields, with the magnitudes currently observed in molecular clouds, affect the structure and evolution of dense cores and protoplanetary disks to form stars and planets.
Intense velocity-shears and magnetic fields in diffuse molecular gas: from 10 pc to 5 mpc
Authors: Falgarone Edith , Hily-Blant Pierre
Published: October 2010

Regions of intense velocity-shears are identified on statistical grounds in nearby diffuse molecular gas: they form conspicuous thin (~ 0.03 pc) and parsec-long structures that do not bear the signatures of shocked gas. Several straight substructures, ~ 3 mpc thick, have been detected at different position-angles within one of them. Two exhibit the largest velocity-shears ever measured far from star forming regions, up to 780 kms−1pc−1. Their position-angles are found to be also those of 10-parsec striations in the I(100μm) dust emission of the large scale environment. The B field projections, where available in these fields, are parallel both to the parsec- and to one of the milliparsec-scale shears. These findings put in relation the small-scale intermittent facet of the gas velocity field and the large scale structure of the magnetic fields.
The role of SN-driven turbulence on the formation of outflows, inflows and cooling flows: from Galaxies to Clusters of Galaxies
Authors: de Gouveia Dal Pino E. M. , Falceta-Gonçalves D. , Gallagher J. S. , Melioli C. , D'Ercole A. , Brighenti F.
Published: October 2010

Star forming galaxies often exhibit hot halos with structures that resemble chimneys and fountains extending for several kpc above the galaxy. Observations indicate that they are probably produced by supernovae (SNe) which blow superbubbles that carve holes in the disk. Through these holes, high speed material is injected and expands buoyantly up to a maximum height and then returns to the disk pulled by the galaxy gravity. This circulating gas in a fountain tends to condense out forming high-velocity clouds and filaments. Starburst galaxies also show evidence that the spectacular winds that arise from their disk are fed by SNe explosions. Similarly, at galaxy cluster scales, most massive clusters exhibit rich filamentary structure of ionized gas which is distributed all around the central galaxy. We discuss here the role that SNe bubbles play in driving outflows and filamentary structures both at galaxy and galaxy-cluster scales. With the help of HD and MHD numerical simulations, we show in particular that SN-driven turbulence may play a key role at helping a central AGN halting and ”isotropize” the cooling flow in the central regions of a galaxy cluster.
Magnetic fields in dwarfs versus early-type galaxies
Authors: Chyży Krzysztof T.
Published: October 2010

According to a recent systematic study of dwarf irregular galaxies the production of their magnetic fields appears to be regulated mainly by the surface density of the galactic star-formation rate. Magnetic fields in nearby dwarfs are typically weak, with the mean value of the total field strength three times smaller than in the normal spirals. Dwarfs with stronger fields reveal vivid star-forming activity, have clear signs of current or recent gravitational interactions, are more massive and evolved systems. Recently discovered strong regular fields in an early-type ringed galaxy NGC 4736 also indicates that even without spiral density waves an effective generation of strong magnetic fields is possible in any type of galaxy if only starburst characteristics are reached.
Magnetic turbulence in clusters of galaxies
Authors: Enßlin T. A. , Clarke T. , Vogt C. , Waelkens A. , Schekochihin A. A.
Published: October 2010

Galaxy clusters are large laboratories for magnetic plasma turbulence and therefore permit us to confront our theoretical concepts of magnetogenesis with detailed observations. Magnetic turbulence in clusters can be studied via the radio-synchrotron emission from the intra-cluster medium in the form of cluster radio relics and halos. The power spectrum of turbulent magnetic fields can be examined via Faraday rotation analysis of extended radio sources. In case of the Hydra A cool core, the observed magnetic spectrum can be understood in terms of a turbulence-mediated feedback loop between gas cooling and the jet activity of the central galaxy. Finally, methods to measure higher-order statistics of the magnetic field using Stokes-parameter correlations are discussed, which permit us to determine the power spectrum of the magnetic tension force. This fourth-order statistical quantity offers a way to discriminate between different magnetic turbulence scenarios and different field structures using radio polarimetric observations.
Cosmic rays in magnetized intracluster plasma
Authors: Feretti L. , Bonafede A. , Giovannini G. , Govoni F. , Murgia M.
Published: October 2010

A breakthrough in the studies of magnetic fields in clusters of galaxies has been reached in recent years from the analysis of the Rotation Measure of sources seen through the magnetized cluster medium (Govoni & Feretti 2004). The results obtained can be summarized as follows: (i) magnetic fields are present in all clusters; (ii) at the center of clusters undergoing merger activity the field strenght is around 1 μG, whereas at the center of relaxed cooling core clusters the intensity is much higher (~ 10 μG); (iii) a model involving a single magnetic field coherence scale is not suitable to describe the observational data, because of different scales of field ordering and tangling.
Models of particle acceleration in galaxy clusters by MHD turbulence
Authors: Brunetti G.
Published: October 2010

Present radio data provide indirect evidence that diffuse radio emission in the central cluster regions may originate from turbulent-acceleration of relativistic particles. I was invited to discuss models of particle acceleration by MHD turbulence in clusters and in these pages I briefly touch the main points of my talk.
NEI Modelling of the ISM - Turbulent Dissipation and Hausdorff Dimension
Authors: de Avillez Miguel A. , Breitschwerdt Dieter
Published: October 2010

High-resolution non-ideal magnetohydrodynamical simulations of the turbulent magnetized ISM, powered by supernovae types Ia and II at Galactic rate, including self-gravity and non-equilibriuim ionization (NEI), taking into account the time evolution of the ionization structure of H, He, C, N, O, Ne, Mg, Si, S and Fe, were carried out. These runs cover a wide range (from kpc to sub-parsec) of scales, providing resolution independent information on the injection scale, extended self-similarity and the fractal dmension of the most dissipative structures.
A Summary of 3-D Reconstructions of the Whole Heliosphere Interval and Comparison with in-Ecliptic Solar Wind Measurements from STEREO, ACE, and Wind Instrumentation
Authors: Bisi Mario M. , Jackson B. V. , Clover J. M. , Hick P. P. , Buffington A. , Tokumaru M.
Published: October 2010

We present a summary of results from simultaneous Solar-Terrestrial Environment Laboratory (STELab) Interplanetary Scintillation (IPS), STEREO, ACE, and Wind observations using three-dimensional reconstructions of the Whole Heliosphere Interval – Carrington rotation 2068. This is part of the world-wide IPS community's International Heliosphysical Year (IHY) collaboration. We show the global structure of the inner heliosphere and how our 3-D reconstructions compare with in-ecliptic spacecraft measurements.
On Cosmic Rays, IP Structures and Geospace Consequences During WHI
Authors: Lago A. Dal , Guarnieri F. L. , da Silva M. R. , Gonzalez W. D. , Braga C. R. , Schuch N. J. , Munakata K. , Kato C. , Bieber J. W. , Kuwabara T. , Tokumaru M. , Duldig M. L. , Humble J. E.
Published: October 2010

This work presents some observations during the period of the Whole Heliosphere Interval (WHI) of the effects of interplanetary (IP) structures on the near-Earth space using three sets of observations: magnetic field and plasma from the Advanced Composition Explorer (ACE) satellite, ground-based cosmic ray data from the Global Muon Detection Network (GMDN) and geomagnetic indices (Disturbance storm-time, Dst, and auroral electrojet index, AE). Since WHI was near minimum solar activity, high speed streams and corotating interaction regions (CIRs) were the dominant structures observed in the interplanetary space surrounding Earth. Very pronounced geomagnetic effects are shown to be correlated to CIRs, especially because they can cause the so-called High-Intensity Long-Duration Continuous AE Activity (HILDCAAs) - Tsurutani and Gonzalez (1987). At least a few high speed streams can be identified during the period of WHI. The focus here is to characterize these IP structures and their geospace consequences.
WHI High-Speed Streams at Geospace
Authors: Maris G. , Maris O.
Published: October 2010

The fast solar wind analysis during the Whole Heliospheric Interval (Carrington Rotation no. 2068: March 20 - April 16, 2008) is herein presented. The analysis is based on the data recorded by space experiments aboard the ACE and SOHO missions. The high-speed streams in the solar wind were determined by their main parameters: duration, maximum velocity, velocity gradient. The fast solar wind was also analyzed during the preceding and following Carrington Rotations, nos. 2067 and 2069, respectively. The main properties of the rapid streams and their solar sources were analysed in terms of the present solar minimum phase. The geospace response to the fast streams was evaluated using the geomagnetic index dynamics. A comparative analysis of the high-speed streams registered during Whole Heliospheric Interval with the ones determined during Whole Sun Month was also made.
The Future of IHY Campaigns: Transition to the International Space Weather Initiative
Authors: Raulin Jean-Pierre , Davila Joseph M. , Bogdan Thomas , Yumoto Kiyohumi , Leibacher John
Published: October 2010

We will present the relevant activities performed during the International Heliophysical Year (IHY) program during the 5 year period 2004 - 2008. The IHY was a major international effort that involved the deployment of new instrumentation, new observations from the ground and in space, and a strong education component. Under the United Nations Office for Outer Space program called Basic Space Science Initiative (UNBSSI), instrument arrays have been deployed to provide global measurements of heliophysical phenomena. As a result, significant scientific and educational collaborations emerged between the organizing groups and the host country teams. In view of the great successes achieved by the IHY during these years, we propose to continue the highly successful collaboration with the UN program to study the universal processes in the solar system that affect the interplanetary and terrestrial environments, and to continue to coordinate the deployment and operation of new and existing instrumentation arrays aimed at understanding the impacts of Space Weather on Earth and the near-Earth environment. To this end, we propose a new program, the International Space Weather Initiative (ISWI). The ISWI strongly complements the International Living With a Star (ILWS) program, providing more attention nationally, regionally, and internationally for the ILWS program. Based on a three-year program activity, the ISWI would provide the opportunity for scientists around the world to participate in this exciting quest to understand the effect of space disturbances on our Earth environment.
SpS1-Infrared and submillimetre-wave spectroscopy as probes of stellar evolution
Authors: Kwok Sun
Published: October 2010

For over a hundred years, optical spectroscopy has been the main tool to study stellar structure and evolution. Photospheric spectra of the electronic transitions of atoms and ions are used to determine the temperature and elemental abundance. Beyond atomic and ionic lines, only the electronic transitions of a few simple molecules (C2, CN, H2O, TiO, CH, etc.) appear in the optical photospheric spectra. With the recent development of infrared and submm spectroscopy, a wide range of molecules have been observed, specially in cool atmospheres of red giants and brown dwarfs. We also realize that beyond the photosphere, a stellar system consists of chromosphere, corona, and stellar wind. Both young and evolved stars possess extensive circumstellar regions and the atoms, molecules, and solid particles in this environment radiate a wide range of lines and bands observable at infrared and submm wavelengths.
SpS1-Preparing for the harvest from large infrared surveys
Authors: Padgett Deborah L.
Published: October 2010

During the past decade, there has been a revolution in the availability of multi-wavelength astronomical surveys. From the Sloan Digital Sky Survey (SDSS) to the NRAO VLA Sky Survey (NVSS), astronomical research based on publicly accessible datasets is becoming standard practice in the community. Beginning with the Infrared Astronomical Satellite (IRAS) mission, infrared surveys have played a critical role in stellar astronomy by identifying cool and dusty stars worthy of spectroscopic characterization. IRAS' four photometric bands at 12, 25, 60, and 100 μm were ideal for detecting dusty circumstellar material. All-sky surveys like IRAS reveal the brightest members of each class of rare objects, optimizing their follow-up strategy. The case of debris disks around main sequence stars demonstrates this utility. IRAS detected dust disks around four nearby stars, Beta Pictoris, Fomalhaut, Epsilon Eridani, and Vega. The “Fabulous Four” remain the best studied debris disks, despite hundreds of additional examples discovered by the Spitzer Space Telescope. In the nearly 30 years since IRAS was launched, its highly reliable catalog of just 250000 sources, modest by modern standards, with arcminute scale resolution and 0.3 - 1 Jy sensitivity, has generated over 10,000 references in ADS. This is a success story by any measure.
Development of jets, outflows and HH objects
Authors: Raga A. C. , López-Cámara D. , Cantó J. , Esquivel A. , Rodríguez-González A. , Velázquez P. F.
Published: October 2010

The entrainment of molecular material through a mixing layer along the walls of a HH jet beam has been modeled analytically (Cantó & Raga 1991; Stahler 1994) and numerically (Taylor & Raga 1995; Lim et al. 1999). However, when full radiative jet simulations are carried out, the molecular, environmental material remains within a dense shell which follows the shape of the leading bow shock. Because of this, no molecular material reaches the outer boundary of the jet beam, and therefore no “side-entrainment” of molecular gas into the fast jet beam takes place.
SpS1-Gas in protoplanetary disks
Authors: Goto Miwa
Published: October 2010

High resolution infrared spectroscopy is the key technique to look at the inner regions of protoplanetary disks. As molecular hydrogen is an inefficient emitter, CO gas is the single most important molecular probe of the disk. The energy gaps of the vibrationally excited levels (ΔE > 3000 K) and the critical density required to keep the molecules in the excited state (nc ~ 1010cm−3) match well to the physical condition of the inner regions of protoplanetary disks. In order to resolve the vibrational lines of different rotational states, a spectral resolving power of λ/Δλ > 10000 is necessary; or even higher (> 30000 –100000), if we would like to fully resolve the gas kinematics. Scoville et al. (1980) provided the fundamentals of the excitation mechanisms, which is essential for the interpretation of the vibrational transitions of CO, and pioneered the study of the circumstellar environment with infrared CO lines in the observation of BN (Scoville et al. (1983)). The bandhead emission of CO at 2.3 μm from young stars was unambiguously attributed to the circumstellar disks by Carr (1989) and Najita et al. (1996), because the gas kinematics matches well to what is expected from Keplerian rotation. Since then, the gas kinematics have been extensively used to shed light on peculiar disk structures, such as the inner truncation (Brittain et al. 2003), the outer truncation (Najita et al. 2008), and the gap (van der Plas et al. 2008; though this is an oxygen forbidden line).
High-resolution near-IR spectroscopy: from 4m to ELT class telescopes
Authors: Oliva E. , Origlia L.
Published: October 2010

High-resolution (HR) near-IR spectroscopy is opening new windows in our understanding of several hot topics of modern planet, stellar and extragalactic astrophysics, and it will have a huge impact in the JWST and ALMA era and beyond. The much reduced extinction at these wavelengths allows to pierce the dust embedding those objects which are heavily obscured in the optical. Moreover, at high redshifts several spectral features, commonly exploited when studying local galaxies, are shifted into the near-IR. However, despite its scientific potential, the field of HR IR spectroscopy and its related science is developing very slowly, because of the lack of optimized instruments with the necessary combination of spectral resolution and coverage.
SpS1-Instrumentation for sub-millimeter spectroscopy
Authors: Rodríguez Luis F.
Published: October 2010

The fields of millimeter and sub-millimeter interferometry have been developing for more than 30 years. At millimeter wavelengths the most important interferometers are the Combined Array for Research in Millimeter-Wave Astronomy (CARMA), the Plateau de Bure Interferometer (PdBI), and the Nobeyama Millimeter Array (NMA). At sub-millimeter wavelenghts, the most powerful interferometer is the SubMillimeter Array (SMA, for a detailed description, see Ho et al. 2004).
SpS1-Silicate dust formation around AGB stars
Authors: Käufl Hans Ulrich , Kerber Florian , Aringer Bernhard
Published: October 2010

VISIR, the VLT Imager and Spectrograph for the Mid-Infrared is a multi-mode instrument, featuring also a high resolution Echelle spectrograph with a spectral resolving power $\frac{\nu}{\Delta \nu}$ of ≈30 000 or 10 km s−1 at ν ≈ 30 000 GHz (λ ≈ 10 μm). A limited long-slit mode as well as a general cross-dispersed mode are available. The Echelle grating is illuminated with a 200 mm diameter collimated beam. Cross-dispersion is achieved by a pair of grisms in the pre-slit optics. The entire frequency interval corresponding to the “10 μ m-window” from 22 400 to 39 500 GHz is fully accessible, albeit sequentially. This interval contains a multitude of fundamental molecular rotational-vibrational bands such as SiO, OH−, H2O, NH3, CH4 and many other hydro-carbonates. Since its commissioning in April 2004, VISIR has been plagued by artifacts introduced from its detector. The cross-dispersed mode is especially handicapped, as it is the most demanding mode for dynamic range of illumination. Now an ambitious upgrade with a pair of newly developed 1k2 As:Si detectors is underway, which will fully resurrect the spectroscopic mode. This will also increase the frequency interval accessible in one exposure by 240% while changing from critical to 3-pixel sampling. Even in the absence of extra spectral features this increase is quite valuable for absorption line spectroscopy, as the limiting factor in analysis often is the definition of the photospheric continuum.
Building-up a database of spectro-photometric standards from the UV to the NIR
Authors: Vernet J. , Kerber F. , Mainieri V. , Rauch T. , Saitta F. , D'Odorico S. , Bohlin R. , Ivanov V. , Lidman C. , Mason E. , Smette A. , Walsh J , Fosbury R. , Goldoni P. , Groot P. , Hammer F. , Kaper L. , Horrobin M. , Kjaergaard-Rasmussen P. , Royer F.
Published: October 2010

We present results of a project aimed at establishing a set of 12 spectro-photometric standards over a wide wavelength range from 320 to 2500 nm. Currently no such set of standard stars covering the near-IR is available. Our strategy is to extend the useful range of existing well-established optical flux standards (Oke 1990, Hamuy et al. 1992, 1994) into the near-IR by means of integral field spectroscopy with SINFONI at the VLT combined with state-of-the-art white dwarf stellar atmospheric models (TMAP, Holberg et al. 2008). As a solid reference, we use two primary HST standard white dwarfs GD71 and GD153 and one HST secondary standard BD+17 4708. The data were collected through an ESO “Observatory Programme” over ~40 nights between February 2007 and September 2008.
Atmospheric water vapour content over La Silla Paranal Observatory
Authors: Querel R. , Kerber F. , Hanuschik R. , Lo Curto G. , Naylor D. , Sarazin M. , Smette A.
Published: October 2010

Water vapour is the principle source of opacity at infrared wavelengths in the earth's atmosphere. Measurements of atmospheric water vapour serve two primary purposes when considering operation of an observatory: long-term monitoring of precipital water vapour (PWV) is useful for characterizing potential observatory sites, and real-time monitoring of PWV is useful for optimizing use, in particular for mid-IR observations.
Atomic data for IR and sub-mm wavelengths
Authors: Nave Gillian
Published: October 2010

Atomic spectra in the infrared and sub-mm wavelength regions can be divided into two broad categories: electric dipole-allowed transitions, and forbidden lines due to transitions within the ground term or between low-lying levels of the same parity. Both are of potential importance in the interpretation of astrophysical spectra. Allowed transitions can provide diagnostic information for stellar photospheres, particularly for elements that are not accessible in the visible region. Electric-dipole forbidden lines are important diagnostics of low-density plasmas, such as nebulae and the interstellar medium. In order to interpret astrophysical spectra, accurate atomic data are required. This paper summarizes the techniques for measuring atomic data and lists the most important compilations and databases.
SpS1-Laboratory spectroscopy of small molecules
Authors: Bernath Peter F.
Published: October 2010

This contribution focuses on the study of ‘cool’ sources with surface temperatures in the range of about 500-4000 K. In this temperature range spectra are dominated by strong molecular absorption and the tools of modern chemical physics can be applied to compute the molecular opacities needed to simulate the observed spectral energy distributions. (See Bernath (2005) for an introduction to molecular spectroscopy including line intensities and Bernath (2009) for a recent astronomical review article.)
SpS1-The evolution of brown dwarf infrared spectroscopic properties
Authors: Allard France , Baraffe Isabelle
Published: October 2010

Brown dwarfs (hereafter BDs) are formed, like stars, by interstellar cloud collapse, but attaining masses of less then 0.075 M⊙ (Baraffe et al. 1998), i.e. too low core temperatures (< 3.5 × 106 K) to stabilize the nuclear burning of the hydrogen PP chain. Therefore, even the most massive BDs begin cooling after some 109 yrs. However, for masses above 0.06 M⊙, core temperatures become hotter than the lithium burning temperature (2.4 x 106 K). All BDs above 0.013 M⊙ (13 MJup) reach core temperatures above the 1.0 x 106 K necessary to burn deuterium from about 107 yrs. The IAU has adopted the definition of the planetary regime as objects having masses below the deuterium burning conditions. But BDs are likely to form well below this limit into the planetary mass regime down to some 5 MJup. It is therefore convenient, in the absence of indices on their formation mechanisms, to call them planetary mass objects or planemos.
Ultra cool dwarfs with companions
Authors: Kurtev R. G. , Ivanov V. D. , Jayawardhana R. , Borissova J. H.
Published: October 2010

The binary fraction in the sub-stellar regime is a topic of discussion. The lower masses of ultra cool dwarfs (UCDs) with respect to the other stars make them even more important because a measurable effect on their radial velocity (RV) or luminosities can be caused by extremely low mass companions. Some UCDs in young star forming regions are bright enough to be studied with existing high resolution instrumentation. The UCDs are intrinsically faint in the optical and the optical RV measurements are affected by “rotationally modulated inhomogeneous surface features” that can mimic a companion, while the near-infrared (NIR) RVs are less prone to them. Therefore, we decided to monitor the RV of six UCDs in the NIR. Blake et al. (2007) demonstrated RV measurement accuracy of 300-600 m s−1 in the NIR using telluric calibration.
FIR and sub-mm line observations of AGB and post-AGB nebulae
Authors: Bujarrabal Valentïn
Published: October 2010

The existing information on asymptotic giant branch (AGB) and post-AGB objects from FIR and submm spectroscopy is still scarce. Observations from the ground are often very difficult to calibrate and show low S/N ratios. However, we expect to obtain in the near future an impressive amount of high-quality data, from the Herschel space telescope. ALMA is also expected to provide high-quality maps of submm lines.
Infrared and sub-mm observations of cataclysmic variables
Authors: Evans A.
Published: October 2010

Although cataclysmic variables (CVs) come in a wide variety of shapes and sizes, the essential ingredients are a compact primary star and a Roche-lobe-filling secondary. In most cases the cool component is a main sequence dwarf, and the compact component a white dwarf (WD). Material from the cool component flows through the inner Lagrangian point via an accretion disc onto the surface of the WD; the flow near the WD is significantly affected by the strength of the magnetic field the WD may have (see Warner for a review of CVs). CVs are characterised by regular eruptions, ranging in energetics and frequency from ‘dwarf novae’, in which eruptions of amplitude ~3-4 mag in the visual occur every few days to weeks, to classical novae (CNe) in which the eruption is explosive, due to thermonuclear runaway (TNR) in material accreted on the surface of the WD (see Bode & Evans for a review of CNe).
Spitzer observations of molecules and dust in evolved stars in nearby galaxies
Authors: Matsuura Mikako
Published: October 2010

Molecules and dust are formed in and around the asymptotic giant branch (AGB) stars and supernovae (SNe), and are ejected into the interstellar medium (ISM) through the stellar wind. The dust and gas contain elements newly synthesised in stars, thus, dying stars play an important role in the chemical enrichment of the ISM of galaxies. However, quantitative analysis of molecules and dust in these stars had been difficult beyond our Galaxy. The high sensitivity instruments on-board the Spitzer Space Telescope (SST; Werner et al. 2004) have enabled us to study dust and molecules in these stars in nearby galaxies. Nearby galaxies have a wide range in metallicity, thus the impact of the metallicity on dust and gas production can be studied. This study will be useful for chemical evolution of galaxies from low to high metallicity.
SpS2-The International Year of Astronomy 2009
Authors: Russo Pedro , Cesarsky Catherine , Christensen Lars Lindberg
Published: October 2010

The International Astronomical Union (IAU) launched 2009 as the International Year of Astronomy (IYA2009) under the theme, The Universe, Yours to Discover. IYA2009 marked the 400th anniversary of the first astronomical observation through a telescope by Galileo Galilei. It has been, and still is, a global celebration of astronomy and its contributions to society and culture, with a strong emphasis on education, public engagement and the involvement of young people, with events at national, regional and global levels throughout the whole of 2009. UNESCO endorsed IYA2009 and the United Nations proclaimed the year 2009 as the International Year of Astronomy on 20 December 2007. These proceedings aim to give a brief account of IYA2009, from its inception to the present and how its legacy will influence the future of astronomy communication on a planet-wide scale.
Astronomy in Antarctica in 2009
Authors: Burton Michael G.
Published: October 2010

This article summarises the subject matter of Special Session 3 at IAU General Assembly XXVII in Rio de Janeiro, Brazil, which took place on August 6-7, 2009. In it, we overview the state of Astronomy in Antarctica as it is in 2009. Significant astronomical activity is now taking place at four stations on the Antarctic plateau (South Pole, Domes A, C & F), as well as at the coastal station of McMurdo.
Astronomy and Astrophysics from Antarctica: a new SCAR Scientific Research Program
Authors: Storey J. W. V.
Published: October 2010

In July 2008 the IAU became a union member of the ICSU body SCAR—the Scientific Committee on Antarctic Research. At the same time, SCAR initiated a Planning Group to establish a Scientific Research Program in Astronomy and Astrophysics from Antarctica. Broadly stated, the objectives of Astronomy and Astrophysics from Antarctica are to coordinate astronomical activities in Antarctica in a way that ensures the best possible outcomes from international investment in Antarctic astronomy, and maximizes the opportunities for productive interaction with other disciplines.
The LUCAS program: detecting vegetation and traces of life in the Earthshine
Authors: Briot Danielle , Arnold Luc , Jacquemoud Stéphane , Schneider Jean , Agabi Karim , Aristidi Eric , Berthier Jérôme , Bondoux Erick , Challita Zalpha , Petermann Denis , Pouzenc Cyprien , Rocher Patrick
Published: October 2010

The aim of the LUCAS program is to observe chlorophyll and atmospheric molecules in the Earthshine spectrum in order to prepare the detection of life in terrestrial extrasolar planets to be discovered. Actually, observations from Antarctica offer a unique possibility to study the variations of Earthshine spectrum during Earth rotation while various parts of Earth are facing the Moon. Special instrumentation for the LUCAS program was designed and put in the Concordia station in the Dome C. Observations are in progress.
Site testing on the Greenland Ice Cap
Authors: Andersen M. I. , Pedersen K. , Sørensen A. N.
Published: October 2010

We present a site testing program initiated at the SUMMIT station on the Greenland Ice Cap. A DIMM was mounted in the SWISS tower, 39 m above the ice level, during a period of 3 weeks in the late Arctic summer 2008. Tracking Polaris, the DIMM obtained continuous seeing measurements. The campaign was hampered by poor weather and the measured seeing was fluctuating, suggesting that the boundary layer was very unstable. However, during short periods, the un-calibrated seeing went below 0″.5, indicating that the free atmosphere seeing above Greenland is not significantly different from what is found above the Antarctic plateau.
CSTAR and future plans for Dome A
Authors: Cui Xiangqun
Published: October 2010

The first set of Chinese Antarctic telescopes at Dome A is called CSTAR. It consists of four 14.5 cm wide-field telescopes and was installed at Dome A during the traverse of 2007/2008. CSTAR successfully operated for 135 days in 2008 and for more than 200 days in 2009. This paper briefly introduces recent developments in Chinese Antarctic astronomy and their international collaborative activities. It also describes future plans for Dome A, as the building of Kunlun Station began in January of this year.