- ID:
- ivo://CDS.VizieR/J/ApJS/236/36
- Title:
- Ga, Ge, As, Kr, Cd, Sn and Pb column densities
- Short Name:
- J/ApJS/236/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive analysis of the gas-phase abundances and depletion behaviors of neutron-capture elements in the interstellar medium (ISM). Column densities (or upper limits to the column densities) of Ga II, Ge II, As II, Kr I, Cd II, Sn II, and Pb II are determined for a sample of 69 sight lines with high- and/or medium-resolution archival spectra obtained with the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope. An additional 59 sight lines with column density measurements reported in the literature are included in our analysis. Parameters that characterize the depletion trends of the elements are derived according to the methodology developed by Jenkins (2009, J/ApJ/700/1299). The depletion patterns exhibited by Ga and Ge comport with expectations based on the depletion results obtained for many other elements. Arsenic exhibits much less depletion than expected, and its abundance in low-depletion sight lines may even be supersolar. We confirm a previous finding by Jenkins that the depletion of Kr increases as the overall depletion level increases from one sight line to another. Cadmium shows no such evidence of increasing depletion. We find a significant amount of scatter in the gas-phase abundances of Sn and Pb. For Sn, at least, the scatter may be evidence of real intrinsic abundance variations due to s-process enrichment combined with inefficient mixing in the ISM.
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- ID:
- ivo://CDS.VizieR/J/MNRAS/473/3671
- Title:
- Galactic bubble infrared fluxes
- Short Name:
- J/MNRAS/473/3671
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the first extended catalogue of far-infrared fluxes of Galactic bubbles. Fluxes were estimated for 1814 bubbles, defined here as the 'golden sample', and were selected from the Milky Way Project First Data Release (Simpson et al., 2012MNRAS.424.2442S, Cat. J/MNRAS/424/2442) The golden sample was comprised of bubbles identified within the Wide-field Infrared Survey Explorer (WISE) dataset (using 12- and 22-um images) and Herschel data (using 70-, 160-, 250-, 350- and 500-um wavelength images). Flux estimation was achieved initially via classical aperture photometry and then by an alternative image analysis algorithm that used active contours. The accuracy of the two methods was tested by comparing the estimated fluxes for a sample of bubbles, made up of 126 HII regions and 43 planetary nebulae, which were identified by Anderson et al. The results of this paper demonstrate that a good agreement between the two was found. This is by far the largest and most homogeneous catalogue of infrared fluxes measured for Galactic bubbles and it is a step towards the fully automated analysis of astronomical datasets.
- ID:
- ivo://CDS.VizieR/J/A+A/626/A44
- Title:
- Galactic center CO rot-vib absorption lines
- Short Name:
- J/A+A/626/A44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the near- to mid-infrared wavelength domain, bright continuum sources in the central parsec of the Galactic center (GC) are subject to foreground absorption. These sources therefore represent ideal probes of the intervening material that is responsible for the absorption along the line of sight. Our aim is to shed light on the location and physics of the absorbing clouds. We try to find out which of the gaseous absorbing materials is intimately associated with the GC and which one is associated with clouds at a much larger distance. We used the capabilities of CRIRES spectrograph located at ESO Very Large Telescope in Chile to obtain absorption spectra of individual lines at a high spectral resolution of R=65000, that is, 5km/s. We observed the 12CO R(0), P(1), P(2), P(3), P(4), P(5), P(6), P(7) and P(9) transition lines, applied standard data reduction, and compared the results with literature data. Results. We present the results of CRIRES observations of 13 infrared sources located in the central parsec of the Galaxy. The data provide direct evidence for a complex structure of the interstellar medium along the line of sight and in the close environment of the central sources. In particular we find four cold foreground clouds at radial velocities vLS R of the order of -145, -85, -60, and -40+\/-15km/s that show absorption in the lower transition lines from R(0) to P(2) and in all the observed spectra.We also find in all sources an absorption in velocity range of 50-60km/s, possibly associated with the so-called 50km/s cloud and suggesting an extension of this cloud in front of the GC. Finally, we detect individual absorption lines that are probably associated with material much closer to the center and with the sources themselves, suggesting the presence of cold gas in the local region.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/67
- Title:
- Galactic CHaMP. III. ^12^CO dense clump properties
- Short Name:
- J/ApJ/831/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the second complete molecular line data release from the Census of High- and Medium-mass Protostars (CHaMP), a large-scale, unbiased, uniform mapping survey at sub-parsec resolution, of millimeter-wave line emission from 303 massive, dense molecular clumps in the Milky Way. This release is for all ^12^CO J=1->0 emission associated with the dense gas, the first from Phase II of the survey, which includes ^12^CO, ^13^CO, and C^18^O. The observed clump emission traced by both ^12^CO and HCO^+^ (from Phase I) shows very similar morphology, indicating that, for dense molecular clouds and complexes of all sizes, parsec-scale clumps contain {Xi}~75% of the mass, while only 25% of the mass lies in extended (>~10pc) or "low density" components in these same areas. The mass fraction of all gas above a density of 10^9^m^-3^ is {xi}_9_>~50%. This suggests that parsec-scale clumps may be the basic building blocks of the molecular interstellar medium, rather than the standard giant molecular cloud (GMC) concept. Using ^12^CO emission, we derive physical properties of these clumps in their entirety, and compare them to properties from HCO^+^, tracing their denser interiors. We compare the standard X-factor converting I_^12^CO_ to N_H2_ with alternative conversions, and show that only the latter give whole-clump properties that are physically consistent with those of their interiors. We infer that the clump population is systematically closer to virial equilibrium than when considering only their interiors, with perhaps half being long-lived (10s of Myr), pressure-confined entities that only terminally engage in vigorous massive star formation, supporting other evidence along these lines that was previously published.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A92
- Title:
- Galactic Cold Cores. IV. Cold sub-mm sources
- Short Name:
- J/A+A/584/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the project Galactic cold cores, Herschel photometric observations were carried out as a follow-up of cold regions of interstellar clouds previously identified with the Planck satellite. The aim of the project is to derive the physical properties of the population of cold sources and to study its connection to ongoing and future star formation. We build a catalogue of cold sources within the clouds in 116 fields observed with the Herschel PACS and SPIRE instruments. We wish to determine the general physical characteristics of the cold sources and to examine the correlations with their host cloud properties. From Herschel data, we compute colour temperature and column density maps of the fields. We estimate the distance to the target clouds and provide both uncertainties and reliability flags for the distances. The getsources multi-wavelength source extraction algorithm is employed to build a catalogue of several thousands of cold sources. Mid-infrared data are used along with a colour and position criteria to separate starless and protostellar sources. We also propose another classification method based on sub-millimetre temperature profiles. We analyse the statistical distributions of the physical properties of the source samples. We provide a catalogue of ~4000 cold sources within or near star forming clouds, most of which are located either in nearby molecular complexes (<1kpc) or in star forming regions of the nearby galactic arms (~2kpc). About 70% of the sources have a size compatible with an individual core, and 35% of those sources are likely gravitationally bound. Significant statistical differences in physical properties are found between starless and protostellar sources, in column density - dust temperature, mass - size, and mass - dust temperature diagrams. The core mass functions are very similar to those previously reported for other regions. On statistical grounds we find that gravitationally bound sources have higher background column densities (median N_bg_(H_2_)~5x10^21^cm-2) than unbound sources (median N_bg_(H_2_)~3x10^21^cm-2). These values of N_bg_(H_2_) are higher for larger dust temperature of the external layers of the parent cloud. However, only in few cases do we find clear N_bg_(H_2_) thresholds for the presence of cores. The dust temperature of cloud external layers shows clear variations with galactic location, as possibly do the source temperatures. Our data support a more complex view of star formation than in the simple idea of a column density threshold. They show a clear influence of the surrounding UV-visible radiation on how cores distribute in their host clouds, with possible variations on the Galactic scale.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A94
- Title:
- Galactic cold cores. VI. List of Herschel fields
- Short Name:
- J/A+A/584/A94
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. The dust opacity spectral index {beta} and the dust colour temperature T are derived using Herschel and Planck data. The relation between {beta} and T is examined for the whole sample and inside individual fields.
- ID:
- ivo://CDS.VizieR/J/ApJ/653/1325
- Title:
- Galactic distribution of infrared dark clouds
- Short Name:
- J/ApJ/653/1325
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using ^13^CO(J=1-0) molecular line emission (112GHz) from the Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey (BU-FCRAO GRS), we have established kinematic distances to 313 infrared dark clouds (IRDCs) by matching the morphology of the molecular line emission in distinct velocity channels to their mid-infrared extinction.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A43
- Title:
- Galactic HI supershells kinetic energies
- Short Name:
- J/A+A/624/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We estimate the Galactic supershell (GS) masses and energies. We developed and used an automatic algorithm. The study was carried out making use of the Leiden-Argentine-Bonn (LAB) HI survey in the outer part of the Galaxy. The algorithm was applied only to a set of GSs from the catalogue of Suad et al. (2014, Cat. J/A+A/564/A116), those showing HI-emission surrounding its central cavity in at least three quarters (or 270 degrees) of its angular extent. A total of 490 GSs fulfilled this criterion. Among them, 308 are completely surrounded by walls of HI-emission (Group A) and in the remaining 182 the central HI minimum is surrounded by ridges of HI emission in at least 270{deg} of its angular extent (Group B).
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1019
- Title:
- Galactic SFR and gas surface densities
- Short Name:
- J/ApJ/723/1019
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the relation between star formation rate (SFR) and gas surface densities in Galactic star-forming regions using a sample of young stellar objects (YSOs) and massive dense clumps. Our YSO sample consists of objects located in 20 large molecular clouds from the Spitzer cores to disks (c2d; Evans, 2009, Cat. J/ApJS/181/321) and Gould's Belt (GB) survey (L. Allen et al. 2010, in preparation). These data allow us to probe the regime of low-mass star formation, essentially invisible to tracers of high-mass star formation used to establish extragalactic SFR-gas relations. We estimate the gas surface density ({Sigma}_gas_) from extinction (A_V_) maps and YSO SFR surface densities ({Sigma}_SFR_) from the number of YSOs, assuming a mean mass and lifetime. We also divide the clouds into evenly spaced contour levels of A_V_, counting only Class I and Flat spectral energy distribution YSOs, which have not yet migrated from their birthplace. For a sample of massive star-forming clumps, we derive SFRs from the total infrared luminosity and use HCN gas maps to estimate gas surface densities. We find that c2d and GB clouds lie above the extragalactic SFR-gas relations (e.g., Kennicutt-Schmidt law) by factors of up to 17. We use ^12^CO and ^13^CO gas maps of the Perseus and Ophiuchus clouds from the COMPLETE survey (Ridge et al. 2006AJ....131.2921R) to estimate gas surface densities and compare to measurements from A_V_ maps.
290. Galactic Worms
- ID:
- ivo://CDS.VizieR/J/ApJ/390/108
- Title:
- Galactic Worms
- Short Name:
- J/ApJ/390/108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of candidates for the Galactic Worms that are possibly the walls surrounding the superbubbles is compiled; 118 isolated structures that appear both in HI and in IR (60 and 100{mu}m). 52 are possibly associated with HII regions. It is found that the 100-{mu}m emissivity increases systematically toward the Galactic interior, which is consistent with the increase of the general interstellar radiation field. The 100-{mu}m emissivity of the structures associated with the HII regions is larger than that of the structures without associated HII regions. The 60-100{mu}m ratio is large, 0.28+/-0.03, which may indicate that the grains associated with the atomic gas have a relatively large population of small grains. 35 structures appear in the 408MHz continuum. The IR and the radio continuum properties suggest that the 408MHz continuum emission in those structures is very likely thermal. The implications of these results on the ionization of gas far from the Galactic plane are discussed.
