bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Properties of Highly Luminous HII Regions in the Interacting Zone of the Antennae Galaxies, and Comparison with the Molecular Cloud Component
Authors: Font Joan , Beckman John E. , Zaragoza Javier , Erroz-Ferrer Santi , Garcia-Lorenzo Begoña 
Published: March 2013

AbstractWe have used the package CLOUDPROPS (Rosolowsky & Leroy 2008) in order to identify clouds, which are contained in data cubes of molecular/Hα line emission, and extract their properties. The molecular data cube is taken from the ALMA public archive and the ionized hydrogen data cube was obtained with the Fabry-Perot interferometer, GHαFaS, on the 4.2 m WHT in La Palma. In our study of the overlap region of the Antennae galaxies we have identified two populations of molecular clouds, above and below log M/M⊙ = 6.75 (in agreement with Wei et al. 2012 who find the break in mass at log M/M⊙ = 6.5) and two different populations of ionized gas clouds; the break in the luminosity occurs near log L = 37.6 (see Fig. 1). We have measured the masses, velocity dispersions and luminosities of the clouds, and derived relation between them for each population. Population II clouds (both molecular and ionized) tend to be located in the most luminous regions, while population I clouds can be found in the outskirts. This work will be published in Font et al. (2013).
Revealing the Physical Properties of GMC Complexes in the Spiral Arms of NGC 6946
Authors: Topal Selçuk , Bayet Estelle , Bureau Martin , Walsh Wilfred , Davis Timothy A. 
Published: March 2013

AbstractIn this study, we probe for the first time the molecular gas physical properties of several star forming regions located in the arms and inter-arms of the spiral galaxy NGC 6946. Combining our observations with additional data found in the literature, we provide in this study the most complete CO ladder ever obtained in these inter-arm and arm regions, i.e. the CO(1-0, 2-1, 3-2, 4-3, 6-5) and 13CO(1-0, 2-1) transitions. For each region studied, we use more precisely the large velocity gradient (LVG) assumption in order to derive the beam-averaged molecular gas physical properties. Namely, we obtained the gas kinetic temperature (i.e. 'best' TK), volume number gas density (i.e. 'best' n(H2)) and CO column density (i.e. 'best' N(CO)) which best reproduce the data for 8 regions investigated. Optical depths were also estimated for a large variety of CO lines in these regions. To identify the best values found, we used two complementary theoretical approaches when comparing the model predictions with the observations, i.e. the χ2 minimisation and the likelihood. Very different physical conditions for the molecular gas from a region to another have been obtained: TK ranges from 10 to 250 K, n(H2) ranges from 102.3 to 107.0 cm−3 and N(CO) ranges from 1015.0 to 1019.3 cm−2 among the arm and inter-arm regions. For each region probed, we also published for the first time the CO spectral line energy distribution (SLED) from CO(1-0) to CO(10-9) for this galaxy, mixing observations and model predictions which provide an essential insight for future follow-up observational programmes. Finally, in this work, we discuss the physical properties we obtained for each region in relation with the presence of young stellar population characteristics such as supernovae remnants (SNRs), Hi holes, Hii regions.
Brightest Cluster Galaxies & Cooling Flows
Authors: Salomé Philippe 
Published: March 2013

AbstractIn the absence of any form of feedback heating, the gas in the central regions of massive relaxed cluster should cool and initiate a cooling flow. The presence/efficiency of an additional heating and the ultimate fate of the cooling gas is the subject of an extensive debate. In the last decade, molecular and atomic gas have been found in many Brightest Cluster Galaxies. I will review these observational results and discuss their implication for galaxy formation/evolution, in the perspective of ALMA.
Probing the cool ISM in galaxies via 21 cm H i absorption
Authors: Allison J. R. , Sadler E. M. , Curran S. J. , Reeves S. N. 
Published: March 2013

AbstractRecent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).
Shards of SHARDS: emission line galaxies
Authors: Cava Antonio , Villar Víctor , Pérez-González Pablo G. ,   the SHARDS Team
Published: March 2013

AbstractSHARDS (Survey for High-z Absorption Red & Dead Sources; see Pérez-González et al. 2012) is an optical ultra-deep spectro-photometric survey with OSIRIS-GTC aimed at selecting and studying massive passively evolving galaxies at z=1.0–2.3 in GOODS-North. Nonetheless, the data quality allow a plethora of studies on galaxy populations, including Emission Line Galaxies (ELGs) about which we have started our first science verification project. The selection procedure, measurement and first analysis of ELGs in SHARDS, demonstrate the huge capability of the survey in providing physical information for a large sample of emitters, spanning from local Hα to high-z Lyman-α emitters.
Morphologies and Substructures of UV Star-Forming Galaxies at Intermediate-z
Authors: Voyer E. N. , de Mello D. F. , Blevins S. M. , Teplitz H. I. , Gardner J. P. , Siana B. D. , Soto E. 
Published: March 2013

AbstractExploring potential links between the internal physical processes of galaxies with respect to their external morphologies can reveal connections between past and present populations. One primary physical driver of galaxy evolution is star formation, which is directly detected from UV emission. Here, we summarize a study investigating the optical and UV morphologies of rest-frame UV-detected star-forming galaxies at intermediate redshifts (0.1<z<1.2) observed with the Hubble Space Telescope (HST) Solar Blind Channel (far-UV) and Wide Field PlanetaryCamera 2 (WFPC2; U-band) in the Great Observatories Origins Deep Survey fields.
The molecular gas in Luminous Infrared Galaxies: a new emergent picture
Authors: Papadopoulos Padelis P. , Zhang Zhi-Yu , Weiss Axel , van der Werf Paul , Isaak Kate , Gao Yu , Xilouris Manolis , Greve Thomas R. 
Published: March 2013

AbstractResults from a large, multi-J CO, 13CO, and HCN line survey of Luminous Infrared Galaxies (LIRGs: LIR≥ 1010 L⊙) in the local Universe (z≤0.1), complemented by CO J=4–3 up to J=13–12 observations from the Herschel Space Observatory (HSO), paints a new picture for the average conditions of the molecular gas of the most luminous of these galaxies with turbulence and/or large cosmic ray (CR) energy densities UCR rather than far-UV/optical photons from star-forming sites as the dominant heating sources. Especially in ULIRGs (LIR>1012 L⊙) the Photon Dominated Regions (PDRs) can encompass at most a few % of their molecular gas mass while the large UCR∼ 103 UCR, Galaxy, and the strong turbulence in these merger/starbursts, can volumetrically heat much of their molecular gas to Tkin∼ (100-200) K, unhindered by the high dust extinctions. Moreover the strong supersonic turbulence in ULIRGs relocates much of their molecular gas at much higher average densities (≥104 cm−3) than in isolated spirals (∼ 102–103 cm−3). This renders low-J CO lines incapable of constraining the properties of the bulk of the molecular gas in ULIRGs, with substantial and systematic underestimates of its mass possible when only such lines are used. Finally a comparative study of multi-J HCN lines and CO SLEDs from J=1–0 up to J=13–12 of NGC 6240 and Arp 193 offers a clear example of two merger/starbursts whose similar low-J CO SLEDs, and LIR/LCO,1−0 and LHCN, 1−0/LCO,1-0 ratios (proxies of the so-called SF efficiency and dense gas mass fraction), yield no indications about their strongly diverging CO SLEDs beyond J=4–3, and ultimately the different physical conditions in their molecular ISM. The much larger sensitivity of ALMA and its excellent site in the Atacama desert now allows the observations necessary to assess the dominant energy sources of the molecular gas and its mass in LIRGs without depending on the low-J CO lines.
Molecular richness of the diffuse interstellar medium: a signpost of turbulent dissipation
Authors: Falgarone Edith , Godard Benjamin , des Forêts Guillaume Pineau , Gerin Maryvonne 
Published: March 2013

AbstractThe Herschel/HIFI absorption spectroscopy surveys reveal the unexpected molecular richness of the Galactic diffuse ISM, even in gas of very low average H2 molecular fraction. In particular, two hydrides, CH+ and SH+ with highly endoergic formation routes have abundances that challenge models of UV-driven chemistry. The intermittent dissipation of turbulence appears as a plausible additional source of energy for the diffuse ISM chemistry. We present recent results of the so-called models of Turbulent Dissipation Regions (TDR). The abundances of many of the molecules observed in the diffuse ISM, including CO that is used as a tracer of the molecular cloud mass, may be understood in the framework of the TDR models.
Densitometry of Active Star Forming Galaxies
Authors: Henkel C. , Mangum J. G. , Darling J. , Menten K. M. 
Published: March 2013

AbstractAttempting to distangle density and kinetic temperature of the star forming molecular gas in the central regions of galaxies, we have embarked on a project involving sensitive measurements of a variety of formaldehyde (H2CO) and ammonia (NH3) transitions. Preliminary results, based on observations from the Green Bank Telescope (GBT) and the Very Large Array (VLA) are summarized and an outline for the entire project is given.
Quantum IR line list of NH3 and isotopologues for ISM and dwarf studies
Authors: Huang Xinchuan , Schwenke David W. , Lee Timothy J. , Sung Keeyoon , Brown Linda R. 
Published: March 2013

AbstractAmmonia (NH3) was the first polyatomic molecule observed in the ISM. Its importance in interstellar molecules is only second to CO because its rovibrational spectroscopic signature can be used very effectively at deducing the conditions of the interstellar environment such as temperature and density, and because it is found in so many different interstellar objects in a wide temperature range. However, experimental determination of NH3 IR spectra is extremely difficult due to the large-amplutide inversion vibration, and the existing HITRAN2008 database for NH3 is limited in temperature, coverage, completeness, and accuracy. With rapid progress in theoretical chemistry and computational resources, now we are able to generate a highly reliable/accurate IR line list of NH3 (and its isotopologues) for astronomical studies. Exact quantum rovibrational computations on an empirically refined potential energy surface (with nonadiabatic corrections included) have achieved accuracies of 0.02-0.05 cm−1 (for line position) and better than 85-95% (for line intensity) for both NH3 and 15NH3 spectra. The unique feature of our work is that our predictions are essentially as accurate as reproducing existing measurements, suitable for synthetic simulation of various astrophysical environments or objects. The reliabilty and accuracy of our predictions for missing bands and higher energies computed on HSL-2 (Fig. 1) have been proved by the most recent high-resolution experiments and extended up to 7000 cm−1. See Huang et al. 2008, Huang et al. 2011, & Sung et al. 2012 for more details.
Molecular Cores in Taurus: Evolution and Dynamics
Authors: Qian Lei , Li Di , Goldsmith Paul 
Published: March 2013

AbstractThe evolution and dynamics of the molecular cores traced by 13CO J = 1 → 0 emission in the Taurus molecular cloud are studied. We performed a systematic examination of the distribution and dynamic state of cores in a large contiguous region, as well as the core ages, which lie between 106 and 107 years. The core velocity dispersion (CVD), which is the variance of the core velocity difference δ v, exhibits a power-law behavior as a function of the apparent separation L, i.e. CVD (km/s) ∝ L (pc)0.7, with similarities to Larson's law for the velocity dispersion of the gas.
Spatial Variation of CO Excitation in High-z Galaxies
Authors: Sharon Chelsea E. , Baker Andrew J. , Harris Andrew I. , Lutz Dieter , Tacconi Linda J. 
Published: March 2013

AbstractPrevious studies of the molecular gas excitation in high-redshift galaxies have focused on galaxy-wide averages of CO line ratios. However, it is possible that these averages hide spatial variation on sub-galactic scales, disguising the true distribution and conditions of the molecular gas within star-forming galaxies. Even in the pre-ALMA era we have begun to see evidence for spatial variation of CO excitation in both rest-UV selected and submillimeter-selected galaxies at z > 2, aided both by the increased frequency coverage of the Jansky Very Large Array (allowing high-resolution observations of the CO(1–0) line, the best tracer for the coldest molecular gas) and by the benefits of gravitational lensing for spatially extended sources. We show new results for multiple high-redshift systems that reveal spatial and/or spectral variations in CO excitation, including an early-stage merger that has different conditions in its two components, thereby illustrating the need for high spatial and spectral resolution mapping in order to accurately characterize the molecular ISM in high-z galaxies.
Rotationally Excited H2 in the Magellanic Clouds
Authors: Xue Rui , Welty Daniel , Wong Tony 
Published: March 2013

AbstractWe have performed a survey study of rotational excited-state H2 Lyman-Werner absorption lines in the entire FUSE Magellanic Clouds Legacy archive. These lines reflect the UV pumping and formation conditions of H2, enabling a more comprehensive study of H2 gas properties, e.g. J-level populations N(J) and b-values (generally indicating the velocity dispersion). Combining with our previous measurements of N(Hi) and N(H2), we derived H2 excitation temperatures, gas volume density n(H), and local UV radiation field strength IUV for each sight line. The results indicate a weaker correlation between n(H) and IUV in Magellanic Clouds than the Galactic sight lines. We also obtained N(H)/E(B − V) ratios from the Spitzer-SAGE and previous CO J = 1 − 0 / Hi 21 cm surveys at sight line locations, using dust modeling and standard line brightness-column density conversion factors. They show a roughly linear correlation with absorption-based N(H)/E(B − V) values, and have a similar scatter (∼0.7 dex) across the LMC and SMC.
ISM Diagnostics: Dust
Authors: Onaka Takashi 
Published: March 2013

AbstractInfrared (IR) observations provide significant information on the lifecycle of dust grains in the interstellar medium (ISM), which is crucial for the understanding of the evolution of matter in the universe. The IR spectral energy distribution (SED) of the dust emission tells us the relative abundance of sub-micron grains, very small grains, and carriers of the unidentified infrared (UIR) emission bands, since they emit the far-IR, the mid-IR, and the UIR bands from the near- to mid-IR, respectively. On the other hand, the UIR emission bands themselves offer a useful means to probe the physical conditions from which the band emission arises because each band is assigned to a specific C-H or C-C vibration mode and because its relative intensity should reflect the properties of the band carriers and the physical conditions of the environment. Here the two diagnostic methods using IR observations are briefly described together with examples of the observational results. Implications for the dust lifecycle are also discussed.
Processing of Interstellar Dust Grains in Galaxies Revealed by AKARI
Authors: Kaneda Hidehiro , Ishihara Daisuke , Kobata Koudai , Kondo Toru , Yamagishi Mitsuyoshi , Yasuda Akiko , Onaka Takashi , Sakon Itsuki , Suzuki Toyoaki 
Published: March 2013

AbstractWith AKARI, we have performed a systematic study of interstellar dust grains in various environments of galaxies. In many cases, the IR emission of dust is an important tool to trace star-forming activities in galaxies. However it is much more than just star-formation tracers. AKARI has revealed the detailed properties of dust grains in regions not relevant to star formation as well, some of which are found not to follow our old empirical knowledge. Because of its unique capabilities, such as near- and far-IR spectroscopy, and all-sky coverage, AKARI has provided new knowledge on the processing of carbonaceous grains including polycyclic aromatic hydrocarbons. We present the latest results obtained from our AKARI observations of the ISM in our Galaxy and nearby galaxies.
The rapid evolution of dust content in galaxies over the last five billion years
Authors: Gomez H. L. , Dunne L. , Smith D. J. B. , da Cunha E. 
Published: March 2013

AbstractThe Herschel-ATLAS (H-ATLAS) will provide an unrivalled sample of galaxies, probing the normal star-forming submillimetre population of galaxies for the first time. Here, we exploit the Science Demonstration Phase (SDP) data to model the evolution of the interstellar content of galaxies in recent history. The most massive H-ATLAS galaxies show a large increase in the dust content five billion years ago compared to the present epoch. These observations are difficult to explain using standard dust models, one possibility could be contributions from a non-stellar source of dust e.g. grain growth in dense clouds; this would imply that less than 10% of dust would be condensed in stellar atmospheres. Alternatively, an initial mass function which becomes top heavy at high star formation rate densities could also explain this discrepancy.
Evolution of ISM Contents of Massive Galaxies from z = 2 to 0.3
Authors: Scoville Nick 
Published: March 2013

AbstractThe mass of ISM in high redshift Galaxies is a major determinant of their morphology, star formation activity and how they will evolve to low redshift. Measurement of the CO lines at z > 0.5 are time consuming, even with the sensitivity of ALMA, and the derived ISM masses are subject to uncertainty in the CO-to-H2 conversion factor. Here I describe a much faster technique— measuring the long wavelength Rayleigh-Jeans dust emission using the spectacular continuum sensitivity of ALMA. Using a metallicity-dependent gas-to-dust abundance ratio derived from studies of low-z galaxies, one then obtains the ISM mass. Initial results from our ALMA Cycle-0 observations are presented for a small sample of stellar-mass selected galaxies in COSMOS. This technique will enable measurement of 100's of galaxies at high-z with observations of typically ∼10 min per galaxy.
Gas and attenuation in galaxies
Authors: Boquien Médéric , Boselli Alessandro , Buat Véronique 
Published: March 2013

AbstractTo determine the spectral energy distribution of galaxies in large numerical simulations, proper treatment of the attenuation is crucial. One of the most common methods in semi–analytic models is to compute the attenuation from the gas surface density. The aim of the present study is to provide new but still simple relations between the gas surface density and the optical depth, directly calibrated on galaxies. To do so we combine multi–wavelength data and perform a pixel–by–pixel analysis on a sample of nearby galaxies. Examination of the influence of these new relations on simulated FUV and IR luminosity functions shows a clear impact compared to older oft–used relations, which in turn could affect the conclusions drawn from studies based on large scale cosmological simulations.
Analysis of the Interstellar Medium Properties of the Herschel Reference Survey Galaxies
Authors: Ciesla Laure ,   the SAG2 Consortium
Published: March 2013

AbstractThe Herschel Reference Survey is a guaranteed time key project aimed at studying the physical properties of the interstellar medium (ISM) of 323 nearby galaxies, covered by multi-wavelength data. This volume limited, K-band selected sample is composed of galaxies spanning the whole range of morphological types and environments. We conduct a statistical study on the ISM properties of nearby galaxies based on the analysis of their SED. To achieve this goal, we fit the data with the models of Draine & Li (2007) to obtain the intensity of interstellar radiation field, the PAH abundance, the contribution of photodissociation regions, and the dust mass.
Expulsion of Dust from Young Stellar Clusters
Authors: Grosbøl P. , Dottori H. 
Published: March 2013

AbstractYoung stellar clusters were identified on deep near-infrared images of 6 nearby, grand-design spirals observed with HAWK-I/VLT. A 90% completeness was reached for cluster complexes with MK = −11.5m (corresponding to masses around 104 M⊙) while the linear resolution was around 40 pc. The distribution of clusters in the (H-K)–(J-H) diagrams revealed two groups of clusters. Comparing with Starburst99 model tracks, the groups could be interpreted as one old population of clusters with low extinction and one consisting of young clusters with visual extinction as high as AV = 7m. The clear separation between the two groups suggests a rapid expulsion of dust from the young clusters.Monte-Carlo models were made assuming a cluster distribution function g(Mc, τ) = Mc−a τ−γ where Mc and τ are cluster mass and age, respectively. Fitting such models to the observed NIR color distributions, it was concluded that the cluster mortality had to be significant with γ = 0.8-1.0. Further, the star formation phase of clusters has to extend over several Myr. Young clusters have high extinctions at least the first 3 Myr but then lose their reddening over a period of around 5 Myr, depending on the exact evolutionary tracks used.
When the Largest Spiral is Formed
Authors: Eufrasio Rafael T. , de Mello Duília F. , Urrutia-Viscarra Fernanda , de Oliveira Claudia Mendes , Dwek Eli 
Published: March 2013

AbstractWe used UV-to-IR archival data to investigate the nature of the giant spiral galaxy, NGC 6872, 65 Mpc away. It belongs to the southern Pavo group and is interacting with a small lenticular galaxy, IC4970. GALEX UV images show a very large part of the galaxy not seen before, making it one of the largest spiral galaxies known, with a physical size greater than 150 kpc. The SED of 17 regions (10 kpc of diameter) across the two arms show a remarkable spatial distribution, as if they were mirror images with respect to their stellar population. However, the last 40 kpc of the northeastern arm are much bluer than any other region of the southwestern one. There is a strong spatial correlation between the NUV luminosity and the distance to the nucleus. The UV data supports the scenario of an interaction at 130 Myr which triggered star formation all over the disk of NGC 6872. The tip of the northeastern arm resembles a tidal dwarf galaxy in the process of formation.