- ID:
- ivo://CDS.VizieR/J/ApJ/661/830
- Title:
- Giant molecular clouds of M33
- Short Name:
- J/ApJ/661/830
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New observations of CO (J=1->0) line emission from M33, using the 25 element BEARS focal plane array at the Nobeyama Radio Observatory 45m telescope, in conjunction with existing maps from the BIMA interferometer and the FCRAO 14m telescope, give the highest resolution (13") and most sensitive ({sigma}_rms_~60mK) maps to date of the distribution of molecular gas in the central 5.5kpc of the galaxy. A new catalog of giant molecular clouds (GMCs) has a completeness limit of 1.3x10^5^M_{sun}_.
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- ID:
- ivo://CDS.VizieR/J/ApJ/699/1092
- Title:
- Giant molecular clouds (SRBY)
- Short Name:
- J/ApJ/699/1092
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The properties of Galactic molecular clouds tabulated by Solomon et al. (SRBY; 1987ApJ...319..730S) are re-examined using the Boston University-FCRAO Galactic Ring Survey of ^13^COJ=1-0 emission. These new data provide a lower opacity tracer of molecular clouds and improved angular and spectral resolution compared with previous surveys of molecular line emission along the Galactic Plane. We calculate giant molecular cloud (GMC) masses within the SRBY cloud boundaries assuming local thermodynamic equilibrium (LTE) conditions throughout the cloud and a constant H_2_ to ^13^CO abundance, while accounting for the variation of the ^12^C/^13^C with galactocentric radius.
- ID:
- ivo://CDS.VizieR/J/A+A/641/A53
- Title:
- Giant molecular filament GMF54 images
- Short Name:
- J/A+A/641/A53
- Date:
- 07 Mar 2022 07:18:57
- Publisher:
- CDS
- Description:
- Recent surveys of the Galactic plane in the dust continuum and CO emission lines reveal that large (>~50pc) and massive (>~10^5^M_{sun}_) filaments, know as giant molecular filaments (GMFs), may be linked to galactic dynamics and trace the mid-plane of the gravitational potential in the Milky Way. Yet our physical understanding of GMFs is still poor. We investigate the dense gas properties of one GMF, with the ultimate goal of connecting these dense gas tracers with star formation processes in the GMF. We have imaged one entire GMF located at l~52-54{deg} longitude, GMF54 (~68pc long), in the empirical dense gas tracers using the HCN(1-0), HNC(1-0), HCO^+^(1-0) lines, and their ^13^C isotopologue transitions, as well as the N_2_H^+^1-0) line. We study the dense gas distribution, the column density probability density functions (N-PDFs) and the line ratios within the GMF. The dense gas molecular transitions follow the extended structure of the filament with area filling factors between 0.06 and 0.28 with respect to ^13^CO(1-0). We constructed the N-PDFs of H_2_ for each of the dense gas tracers based on their column densities and assumed uniform abundance. The N-PDFs of the dense gas tracers appear curved in log-log representation, and the HCO^+^ NPDF has the largest log-normal width and flattest power-law slope index. Studying the N-PDFs for sub-regions of GMF54, we found an evolutionary trend in the N-PDFs that high-mass star forming and Photon Dominated Regions (PDRs) have flatter power-law indices. The integrated intensity ratios of the molecular lines in GMF54 are comparable to those in nearby galaxies. In particular, the N_2_H^+^/^13^CO ratio, which traces the dense gas fraction, has similar values in GMF54 and all nearby galaxies except Ultraluminous Infrared Galaxies (ULIRGs). As the largest coherent cold gaseous structure in our Milky Way, GMFs, are outstanding candidates for connecting studies of star formation on Galactic and extragalactic scales. By analyzing a complete map of the dense gas in a GMF we have found that: (1) the dense gas N-PDFs appear flatter in more evolved regions and steeper in younger regions, and (2) its integrated dense gas intensity ratios are similar to those of nearby galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A131
- Title:
- Giant molecular filaments in the Milky Way
- Short Name:
- J/A+A/590/A131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to the large-scale, Galactic spiral arm structure. Addressing the nature of these giant molecular filaments (GMFs) requires a census of their occurrence and properties. We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. We perform a systematic search of GMFs in the fourth Galactic quadrant and determine their basic physical properties. Methods. We identify GMFs based on their dust extinction signatures in the near- and mid-infrared and the velocity structure probed by ^13^CO line emission. We use the ^13^CO line emission and ATLASGAL dust emission data to estimate the total and dense gas masses of the GMFs. We combine our sample with an earlier sample from literature and study the Galactic environment of the GMFs.
- ID:
- ivo://CDS.VizieR/J/A+A/634/A139
- Title:
- Giant Molecular Filament THOR datacubes
- Short Name:
- J/A+A/634/A139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Molecular clouds form from the atomic phase of the interstellar medium. However, characterizing the transition between the atomic and the molecular interstellar medium (ISM) is a complex observational task. Here we address cloud formation processes by combining HI self absorption (HISA) with molecular line data. Column density probability density functions (N-PDFs) are a common tool for examining molecular clouds. One scenario proposed by numerical simulations is that the N-PDF evolves from a log-normal shape at early times to a power-law-like shape at later times. To date, investigations of N-PDFs have been mostly limited to the molecular component of the cloud. In this paper, we study the cold atomic component of the giant molecular filament GMF38.1-32.4a (GMF38a, distance=3.4kpc, length~230pc), calculate its N-PDFs, and study its kinematics. We identify an extended HISA feature, which is partly correlated with the ^13^CO emission. The peak velocities of the HISA and 13CO observations agree well on the eastern side of the filament, whereas a velocity offset of approximately 4km/s is found on the western side. The sonic Mach number we derive from the linewidth measurements shows that a large fraction of the HISA, which is ascribed to the cold neutral medium (CNM), is at subsonic and transonic velocities. The column density of the CNM part is on the order of 10^20^ to 10^21^cm^-2^. The column density of molecular hydrogen, traced by ^13^CO, is an order of magnitude higher. The N-PDFs from HISA (CNM), HI emission (the warm and cold neutral medium), and 13CO (molecular component) are well described by log-normal functions, which is in agreement with turbulent motions being the main driver of cloud dynamics. The N-PDF of the molecular component also shows a power law in the high column-density region, indicating self-gravity. We suggest that we are witnessing two different evolutionary stages within the filament. The eastern subregion seems to be forming a molecular cloud out of the atomic gas, whereas the western subregion already shows high column density peaks, active star formation, and evidence of related feedback processes.
- ID:
- ivo://CDS.VizieR/J/AJ/89/636
- Title:
- Giant M stars in Baade's Window
- Short Name:
- J/AJ/89/636
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared small-dispersion spectra obtained with a grism at the prime focus of CTIO's 4-m telescope have been used to survey and classify late-type red giants found in a circular area with a diameter of 24.4 arcmin which is contained within Baade's Window. The survey is complete to a distance that extends past the galactic nuclear bulge. The presented stars therefore constitute a unique complete sample of the red giant population of the nuclear bulge. A total of 306 red giants, including all giants of type M6 or later, are presented with a list of their coordinates, spectral classes, and apparent I magnitudes. A finding chart is also given. No C or S stars were found even though they should have been detected if they exist. Evidence is presented of uneven foreground interstellar obscuration in Baade's Window.
- ID:
- ivo://CDS.VizieR/J/ApJ/874/L31
- Title:
- Giant planet bulk and atmosphere metallicities
- Short Name:
- J/ApJ/874/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Atmospheric characterization through spectroscopic analysis, an essential tool of modern exoplanet science, can benefit significantly from the context provided by the interior structure models. In particular, the planet's bulk metallicity, Zp, places an upper limit on the potential atmospheric metallicity. Here we construct interior structure models to derive Zp and atmospheric metallicity upper limits for 403 known transiting giant exoplanets. These limits are low enough that they can usefully inform atmosphere models. Additionally, we argue that comparing Zp to the observed atmospheric metallicity gives a useful measure of how well mixed metals are within the planet. This represents a new avenue for learning about planetary interiors. To aid in the future characterization of new planet discoveries we derive analytic prior predictions of atmosphere metallicity as a function of planet mass, and evaluate the effectiveness of our approach on Jupiter and Saturn. We include log-linear fits for approximating the metallicities of planets not in our catalog.
- ID:
- ivo://CDS.VizieR/J/other/Galax/9.99
- Title:
- Giant Radio Galaxies in RACS
- Short Name:
- J/other/Galax/9.
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We report the results of a visual inspection of images of the Rapid ASKAP Continuum Survey (RACS) in search of extended radio galaxies (ERG) that reach or exceed linear sizes on the order of one Megaparsec. We searched a contiguous area of 1059deg^2^ from RA=20h20m to 06h20m, and -50{deg}<Dec<-40{deg} which is covered by deep multi-band optical images of the Dark Energy Survey (DES), and in which previously only three ERGs larger than 1Mpc had been reported. For over 1800 radio galaxy candidates inspected, our search in optical and infrared images resulted in hosts for 1440 ERG, for which spectroscopic and photometric redshifts from various references were used to convert their largest angular size (LAS) to projected linear size (LLS). This resulted in 178 newly discovered giant radio sources (GRS) with LLS>1Mpc, of which 18 exceed 2Mpc and the largest one is 3.4Mpc. Their redshifts range from 0.02 to about 2.0, but only 10 of the 178 new GRS have spectroscopic redshifts. For the 146 host galaxies the median r-band magnitude and redshift are 20.9 and 0.64, while for the 32 quasars or candidates these are 19.7 and 0.75. Merging the six most recent large compilations of GRS results in 458 GRS larger than 1Mpc, so we were able to increase this number by about 39 per cent to now 636.
- ID:
- ivo://CDS.VizieR/J/ApJS/253/25
- Title:
- Giant radio quasars from SDSS, FIRST & NVSS
- Short Name:
- J/ApJS/253/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the largest sample of giant radio quasars (GRQs), which are defined as having a projected linear size greater than 0.7Mpc. The sample consists of 272 GRQs, of which 174 are new objects discovered through cross-matching the NRAO Very Large Array Sky Survey and the Sloan Digital Sky Survey 14th Data Release Quasar Catalog (DR14Q) and confirmed using Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) radio maps. In our analysis we compare the GRQs with 367 smaller, lobe-dominated radio quasars found using our search method, as well as with quasars from the SDSS DR14Q, investigating the parameters characterizing their radio emission (i.e., total and core radio luminosity, radio core prominence), optical properties (black hole masses, accretion rates, distribution in Eigenvector 1 plane) and infrared colors. For the GRQs and smaller radio quasars we find a strong correlation between [OIII] luminosity and radio luminosity at 1.4GHz, indicating a strong connection between radio emission and conditions in the narrow-line region. We spot no significant differences between GRQs and smaller radio quasars, however we show that most extended radio quasars belong to a quasar population of evolved active galactic nuclei with large black hole masses and low accretion rates. We also show that GRQs have bluer W2-W3 colors compared to SDSS quasars with FIRST detections, indicating differences in the structure of the dusty torus.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/851
- Title:
- Giant Radio Quasars properties
- Short Name:
- J/MNRAS/426/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analysed the optical and radio properties of lobe-dominated giant-sized (>0.72Mpc) radio quasars and compared the results with those derived for a sample of smaller radio sources to determine whether the large size of some extragalactic radio sources is related to the properties of their nuclei. We compiled the largest (to date) sample of giant radio quasars, including 24 new and 21 previously known objects, and calculated a number of important parameters of their nuclei such as the black hole mass and the accretion rate.