- ID:
- ivo://CDS.VizieR/J/ApJS/209/2
- Title:
- The BGPS. X. Dense molecular gas
- Short Name:
- J/ApJS/209/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Bolocam Galactic Plane Survey (BGPS) is a 1.1 mm continuum survey of dense clumps of dust throughout the Galaxy covering 170deg^2^. We present spectroscopic observations using the Heinrich Hertz Submillimeter Telescope of the dense gas tracers, HCO^+^ and N_2_H^+^3-2, for all 6194 sources in the BGPS v1.0.1 catalog between 7.5{deg}<=l<=194{deg}. This is the largest targeted spectroscopic survey of dense molecular gas in the Milky Way to date. We find unique velocities for 3126 (50.5%) of the BGPS v1.0.1 sources observed. Strong N_2_H^+^ 3-2 emission (T_mb_>0.5K) without HCO^+^ 3-2 emission does not occur in this catalog. We characterize the properties of the dense molecular gas emission toward the entire sample. HCO^+^ is very sub-thermally populated and the 3-2 transitions are optically thick toward most BGPS clumps. The median observed line width is 3.3 km/s consistent with supersonic turbulence within BGPS clumps. We find strong correlations between dense molecular gas integrated intensities and 1.1 mm peak flux and the gas kinetic temperature derived from previously published NH_3_observations. These intensity correlations are driven by the sensitivity of the 3-2 transitions to excitation conditions rather than by variations in molecular column density or abundance. We identify a subset of 113 sources with stronger N_2_H^+^ than HCO^+^ integrated intensity, but we find no correlations between the N_2_H^+^/HCO^+^ ratio and 1.1 mm continuum flux density, gas kinetic temperature, or line width. Self-absorbed profiles are rare (1.3%).
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- ID:
- ivo://CDS.VizieR/J/ApJ/721/137
- Title:
- The Bolocam Galactic Plane Survey (BGPS)
- Short Name:
- J/ApJ/721/137
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Bolocam Galactic Plane Survey (BGPS) data for a 6deg^2^ region of the Galactic plane containing the Galactic center are analyzed and compared to infrared and radio continuum data. The BGPS 1.1mm emission consists of clumps interconnected by a network of fainter filaments surrounding cavities, a few of which are filled with diffuse near-IR emission indicating the presence of warm dust or with radio continuum characteristic of HII regions or supernova remnants. New 350um images of the environments of the two brightest regions, Sgr A and B, are presented. Sgr B2 is the brightest millimeter-emitting clump in the Central Molecular Zone (CMZ) and may be forming the closest analog to a super star cluster in the Galaxy. The CMZ contains the highest concentration of millimeter- and submillimeter-emitting dense clumps in the Galaxy. Most 1.1mm features at positive longitudes are seen in silhouette against the 3.6-24um background observed by the Spitzer Space Telescope. However, only a few clumps at negative longitudes are seen in absorption, confirming the hypothesis that positive longitude clumps in the CMZ tend to be on the near side of the Galactic center, consistent with the suspected orientation of the central bar in our Galaxy. The Bolocat catalog of 1.1mm clumps contains 1428 entries in the Galactic center between l=358.5{deg} and l=4.5{deg} of which about 80% are likely to be within about 500pc of the center.
- ID:
- ivo://CDS.VizieR/J/ApJS/195/14
- Title:
- The Bolocam Galactic Plane Survey (BGPS). V.
- Short Name:
- J/ApJS/195/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of observations of 1882 sources in the Bolocam Galactic Plane Survey (BGPS) at 1.1mm with the 10m Henrich Hertz Telescope simultaneously in HCO^+^J=3-2 and N_2_H^+^J=3-2. We detect 77% of these sources in HCO^+^ and 51% in N_2_H^+^ at greater than 3{sigma}. We find a strong correlation between the integrated intensity of both dense gas tracers and the 1.1mm dust emission of BGPS sources. We determine kinematic distances for 529 sources (440 in the first quadrant breaking the distance ambiguity and 89 in the second quadrant). We derive the size, mass, and average density for this subset of clumps. The median size of BGPS clumps is 0.75pc with a median mass of 330M_{sun}_ (assuming T_Dust_=20K). BGPS clumps represent a wide range of objects (from dense cores to more diffuse clumps) and are typically characterized by larger sizes and lower densities than previously published surveys of high-mass star-forming regions.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/66
- Title:
- The CGM-GRB study. I. GRB hosts at z~2-6
- Short Name:
- J/ApJ/884/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent studies have revealed a dynamic interplay between the galaxy ecosystem and circumgalactic medium (CGM). We investigate the CGM at high redshifts (z>~2) by using bright afterglows of gamma-ray bursts (GRBs) as background sources. We compiled a sample of medium-resolution ({Delta}v<50km/s) and high signal-to-noise ratio (typical S/N~10) spectra from 27 GRB afterglows covering z~2-6, with six of them at z>~4. We analyzed the high- and low-ionization absorption features within +/-400km/s to extract the CGM and interstellar medium (ISM) kinematics. In the stacked spectra, high-ionization absorption profiles (e.g., CIV, SiIV) present significant absorption excess in their blue wings (v{<}-100km/s) relative to the red wings (v>100km/s). The stronger blue wings in high-ionization species are indicative of the presence of ubiquitous warm outflows in the GRB hosts at high redshifts. We used simple toy models to kinematically distinguish the CGM and ISM absorption and estimate the CGM mass and outflow velocity. We find tentative evidence of the evolution of the CGM metal mass by ~0.5dex between two redshift bins, each spanning 1 Gyr, z1: 2-2.7 and z2: 2.7-5. By comparing with past studies, we find that over the course of evolution of present-day galaxies with M_*_>10^10^M_{sun}_, the ratio of CIV mass in the CGM to the stellar mass remains fairly uniform, with log(M_CIV_/M_*_)~-4.5 within +/-0.5dex from z~4 to z~0, suggesting CGM-galaxy coevolution.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A76
- Title:
- The ESO DIBs Large Exploration Survey
- Short Name:
- J/A+A/606/A76
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the C^+^_60_ fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectral-type stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution (R~70000-100000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305-1042nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided.
- ID:
- ivo://CDS.VizieR/J/A+A/579/A29
- Title:
- The GUViCS FUV diffuse emission
- Short Name:
- J/A+A/579/A29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Virgo direction has been observed at many wavelengths in recent years, in particular in the ultraviolet with GALEX. The far ultraviolet (FUV) diffuse light detected by GALEX offers interesting information on the large scale distribution of Galactic dust, owing to the GALEX FUV band sensitivity and resolution. We aim to characterise the ultraviolet large scale distribution of diffuse emission in the Virgo direction. A map of this emission may become useful for various studies by identifying regions where dust affects observations by either scattering light or absorbing radiation.
- ID:
- ivo://CDS.VizieR/J/AJ/158/169
- Title:
- The hot gas exhaust of starburst engines in mergers
- Short Name:
- J/AJ/158/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using archival data from the Chandra X-ray telescope, we have measured the spatial extent of the hot interstellar gas in a sample of 49 nearby interacting galaxy pairs, mergers, and merger remnants. For systems with SFR>1 M_{sun}_/yr, the volume and mass of hot gas are strongly and linearly correlated with the star formation rate (SFR). This supports the idea that stellar/supernovae feedback dominates the production of hot gas in these galaxies. We compared the mass of X-ray-emitting hot gas M_X_(gas) with the molecular and atomic hydrogen interstellar gas masses in these galaxies (M_H2_ and M_HI_, respectively), using published carbon monoxide and 21 cm H I measurements. Systems with higher SFRs have larger M_X_(gas)/(M_H2_ + M_HI_) ratios on average, in agreement with recent numerical simulations of star formation and feedback in merging galaxies. The M_X_(gas)/(M_H2_ + M_HI_) ratio also increases with dust temperature on average. The ratio M_X_(gas)/SFR is anticorrelated with the Infrared Astronomical Satellite 60-100 {mu}m flux ratio and with the Spitzer 3.6-24 {mu}m color. These trends may be due to variations in the spatial density of young stars, the stellar age, the ratio of young to old stars, the initial mass function, and/or the efficiency of stellar feedback. Galaxies with low SFR (<1 M_{sun}_/yr) and high K band luminosities may have an excess of hot gas relative to the relation for higher SFR galaxies, while galaxies with low K band luminosities (and therefore low stellar masses) may have a deficiency in hot gas, but our sample is not large enough for strong statistical significance.
- ID:
- ivo://CDS.VizieR/J/A+A/617/A38
- Title:
- The hydrogen gas outflow in 3C236
- Short Name:
- J/A+A/617/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The energetic feedback that is generated by radio jets in active galactic nuclei (AGNs) has been suggested to be able to produce fast outflows of atomic hydrogen (HI) gas which can be studied in absorption at high spatial resolution. We have used the Very Large Array (VLA) and a global very-long-baseline-interferometry (VLBI) array to locate and study in detail the HI outflow discovered with the Westerbork Synthesis Radio Telescope (WSRT) in the restarted radio galaxy 3C 236. Based on the VLA data, the presence of a blue-shifted wing of the HI with a width of ~1000km/s. This HI outflow is partially recovered by the VLBI observation. In particular, we detect four clouds with masses of 0.28-1.5x10^4^M_{sun}_ with VLBI that do not follow the regular rotation of most of the HI. Three of these clouds are located, in projection, against the nuclear region on scales of <~40pc, while the fourth is cospatial to the southeast lobe at a projected distance of ~270pc. Their velocities are between 150 and 640km/s blueshifted with respect to the velocity of the disk-related HI. These findings suggest that the outflow is at least partly formed by clouds, as predicted by some numerical simulations, and that it originates already in the inner (few tens of pc) region of the radio galaxy. Our results indicate that the entire outflow might consist of many clouds, possibly with comparable properties as those clearly detected, but also distributed at larger radii from the nucleus where the lower brightness of the lobe does not allow us to detect them. However, we cannot rule out a diffuse component of the outflow. Because 3C 236 is a low excitation radio galaxy, it is less likely that the optical AGN is able to produce strong radiative winds. This leaves the radio jet as the main driver for the HI outflow.
- ID:
- ivo://CDS.VizieR/J/ApJ/837/40
- Title:
- The MASSIVE survey. VI. Warm ionized gas.
- Short Name:
- J/ApJ/837/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first systematic investigation of the existence, spatial distribution, and kinematics of warm ionized gas as traced by the [OII]3727{AA} emission line in 74 of the most massive galaxies in the local universe. All of our galaxies have deep integral-field spectroscopy from the volume- and magnitude-limited MASSIVE survey of early-type galaxies with stellar mass log(M_*_/M_{sun}_)>11.5 (M_K_<-25.3mag) and distance D<108Mpc. Of the 74 galaxies in our sample, we detect warm ionized gas in 28, which yields a global detection fraction of 38+/-6% down to a typical [OII] equivalent width limit of 2{AA}. MASSIVE fast rotators are more likely to have gas than MASSIVE slow rotators with detection fractions of 80+/-10% and 28+/-6%, respectively. The spatial extents span a wide range of radii (0.6-18.2kpc; 0.1-4R_e_), and the gas morphologies are diverse, with 17/28~61+/-9% being centrally concentrated, 8/28~29+/-9% exhibiting clear rotation out to several kiloparsecs, and 3/28~11+/-6% being extended but patchy. Three out of four fast rotators show kinematic alignment between the stars and gas, whereas the two slow rotators with robust kinematic measurements available exhibit kinematic misalignment. Our inferred warm ionized gas masses are roughly ~10^5^M_{sun}_. The emission line ratios and radial equivalent width profiles are generally consistent with excitation of the gas by the old underlying stellar population. We explore different gas origin scenarios for MASSIVE galaxies and find that a variety of physical processes are likely at play, including internal gas recycling, cooling out of the hot gaseous halo, and gas acquired via mergers.
- ID:
- ivo://CDS.VizieR/J/ApJ/784/3
- Title:
- The PAWS catalogs of GMCs and islands in M51
- Short Name:
- J/ApJ/784/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using data from the PdBI Arcsecond Whirlpool Survey (PAWS), we have generated the largest extragalactic giant molecular cloud (GMC) catalog to date, containing 1507 individual objects. GMCs in the inner M51 disk account for only 54% of the total ^12^CO(1-0) luminosity of the survey, but on average they exhibit physical properties similar to Galactic GMCs. We do not find a strong correlation between the GMC size and velocity dispersion, and a simple virial analysis suggests that ~30% of GMCs in M51 are unbound. We have analyzed the GMC properties within seven dynamically motivated galactic environments, finding that GMCs in the spiral arms and in the central region are brighter and have higher velocity dispersions than inter-arm clouds. Globally, the GMC mass distribution does not follow a simple power-law shape. Instead, we find that the shape of the mass distribution varies with galactic environment: the distribution is steeper in inter-arm region than in the spiral arms, and exhibits a sharp truncation at high masses for the nuclear bar region. We propose that the observed environmental variations in the GMC properties and mass distributions are a consequence of the combined action of large-scale dynamical processes and feedback from high-mass star formation. We describe some challenges of using existing GMC identification techniques for decomposing the ^12^CO(1-0) emission in molecule-rich environments, such as M51's inner disk.
