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1481. HELGA VI. Giant molecular cloud associations in M31
ID:
ivo://CDS.VizieR/J/ApJ/798/58
Title:
HELGA VI. Giant molecular cloud associations in M31
Short Name:
J/ApJ/798/58
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we present a catalog of giant molecular clouds (GMCs) in the Andromeda (M31) galaxy extracted from the Herschel Exploitation of Local Galaxy Andromeda (HELGA) data set. GMCs are identified from the Herschel maps using a hierarchical source extraction algorithm. We present the results of this new catalog and characterize the spatial distribution and spectral energy properties of its clouds based on the radial dust/gas properties found by Smith et al. (Paper II, 2012ApJ...756...40S). A total of 326 GMCs in the mass range 10^4^-10^7^M_{sun}_ are identified; their cumulative mass distribution is found to be proportional to M^-2.34^, in agreement with earlier studies. The GMCs appear to follow the same correlation of cloud mass to L_CO_ observed in the Milky Way. However, comparison between this catalog and interferometry studies also shows that the GMCs are substructured below the Herschel resolution limit, suggesting that we are observing associations of GMCs. Following Gordon et al. (2006ApJ...638L..87G), we study the spatial structure of M31 by splitting the observed structure into a set of spiral arms and offset rings. We fit radii of 10.3 and 15.5kpc to the two most prominent rings. We then fit a logarithmic spiral with a pitch angle of 8.9{deg} to the GMCs not associated with either ring. Last, we comment on the effects of deprojection on our results and investigate the effect different models for M31's inclination will have on the projection of an unperturbed spiral arm system.
1482. Hercules A LOFAR and JVLA images
ID:
ivo://CDS.VizieR/J/A+A/658/A5
Title:
Hercules A LOFAR and JVLA images
Short Name:
J/A+A/658/A5
Date:
22 Feb 2022
Publisher:
CDS
Description:
The prominent radio source Hercules A features complex structures in its radio lobes. Despite being one of the most comprehensively studied sources in the radio sky, the origin of the ring structures in the Hercules A radio lobes remains an open question. We present the first sub-arcsecond angular resolution images at low frequencies (<300MHZ) of Hercules A, made with the International LOFAR Telescope. With the addition of data from the Karl G. Jansky Very Large Array, we map the structure of the lobes from 144MHz to 7GHz. We explore the origin of the rings within the lobes of Hercules A, and test whether their properties are best described by a shock model where shock waves are produced by the jet propagating in the radio lobe, or an inner-lobe model in which the rings are formed by decelerated jetted plasma. From spectral index mapping, our large frequency coverage reveals that the curvature of the different ring spectra increases with distance away from the central active galactic nucleus. We demonstrate that the spectral shape of the rings is consistent with synchrotron aging, which speaks in favor of an inner-lobe model, where the rings are formed from the deposition of material from past periods of intermittent core activity.
1483. HerMES Large Mode Survey catalogue
ID:
ivo://CDS.VizieR/J/MNRAS/462/1989
Title:
HerMES Large Mode Survey catalogue
Short Name:
J/MNRAS/462/1989
Date:
21 Oct 2021
Publisher:
CDS
Description:
Selecting sources with rising flux densities towards longer wavelengths from Herschel/Spectral and Photometric Imaging Receiver (SPIRE) maps is an efficient way to produce a catalogue rich in high-redshift (z>4) dusty star-forming galaxies. The effectiveness of this approach has already been confirmed by spectroscopic follow-up observations, but the previously available catalogues made this way are limited by small survey areas. Here we apply a map-based search method to 274deg^2^ of the Herschel Multi-tiered Extragalactic Survey (HerMES) Large Mode Survey and create a catalogue of 477 objects with SPIRE flux densities S_500_>S_350_>S_250_ and a 5{sigma} cut-off S_500_>52mJy. From this catalogue we determine that the total number of these 'red' sources is at least an order of magnitude higher than predicted by galaxy evolution models. These results are in agreement with previous findings in smaller HerMES fields; however, due to our significantly larger sample size we are also able to investigate the shape of the red source counts for the first time. We have obtained spectroscopic redshift measurements for two of our sources using the Atacama Large Millimeter/submillimeter Array. The redshifts z=5.1 and 3.8 confirm that with our selection method we can indeed find high-redshift dusty star-forming galaxies.
1484. Herschel-ATLAS DR1 (HATLAS)
ID:
ivo://CDS.VizieR/J/MNRAS/462/3146
Title:
Herschel-ATLAS DR1 (HATLAS)
Short Name:
J/MNRAS/462/3146
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first major data release of the largest single key-project in area carried out in open time with the Herschel Space Observatory. The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 600 deg^2^ in five photometric bands - 100, 160, 250, 350 and 500 microns - with the Photoconductor Array Camera and Spectrometer and Spectral and Photometric Imaging Receiver (SPIRE) cameras. In this paper and the companion (Bourne at al., 2016MNRAS.462.1714B), we present the survey of three fields on the celestial equator, covering a total area of 161.6 deg2 and previously observed in the Galaxy and Mass Assembly (GAMA) spectroscopic survey. This paper describes the Herschel images and catalogues of the sources detected on the SPIRE 250 micron images. The 1 sigma noise for source detection, including both confusion and instrumental noise, is 7.4, 9.4 and 10.2mJy at 250, 350 and 500 microns. Our catalogue includes 120 230 sources in total, with 113 995, 46 209 and 11 011 sources detected at >4 sigma at 250, 350 and 500 microns. The catalogue contains detections at >3{sigma} at 100 and 160 microns for 4650 and 5685 sources, and the typical noise at these wavelengths is 44 and 49mJy. We include estimates of the completeness of the survey and of the effects of flux bias and also describe a novel method for determining the true source counts. The H-ATLAS source counts are very similar to the source counts from the deeper HerMES survey at 250 and 350 microns, with a small difference at 500 microns.
1485. Herschel-ATLAS (H-ATLAS) DR2
ID:
ivo://CDS.VizieR/J/ApJS/236/30
Title:
Herschel-ATLAS (H-ATLAS) DR2
Short Name:
J/ApJS/236/30
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) is a survey of 660deg^2^ with the PACS and SPIRE cameras in five photometric bands: 100, 160, 250, 350, and 500{mu}m. This is the second of three papers describing the data release for the large fields at the south and north Galactic poles (NGP and SGP). In this paper we describe the catalogs of far-infrared and submillimeter sources for the NGP and SGP, which cover 177.1deg^2^ and 303.4deg^2^, respectively. The catalogs contain 118980 sources for the NGP field and 193527 sources for the SGP field detected at more than 4{sigma} significance in any of the 250, 350, or 500{mu}m bands. The source detection is based on the 250{mu}m map, and we present photometry in all five bands for each source, including aperture photometry for sources known to be extended. The rms positional accuracy for the faintest sources is about 2.4" in both RA and DEC. We present a statistical analysis of the catalogs and discuss the practical issues-completeness, reliability, flux boosting, accuracy of positions, accuracy of flux measurements-necessary to use the catalogs for astronomical projects.
1486. Herschel-ATLAS Science Demonstration Catalog
ID:
ivo://CDS.VizieR/J/MNRAS/415/2336
Title:
Herschel-ATLAS Science Demonstration Catalog
Short Name:
J/MNRAS/415/2336
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) is a survey of 550deg^2^ with the Herschel Space Observatory in five far-infrared and submillimetre bands. The first data for the survey, observations of a field 4x4deg^2^ in size, were taken during the Science Demonstration Phase (SDP), and reach a 5{sigma} noise level of 33.5mJy/beam at 250um. This paper describes the source extraction methods used to create the corresponding SDP catalogue, which contains 6876 sources, selected at 250um, within ~14deg^2^.
1487. Herschel Bright Sources (HerBS)
ID:
ivo://CDS.VizieR/J/MNRAS/473/1751
Title:
Herschel Bright Sources (HerBS)
Short Name:
J/MNRAS/473/1751
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the Herschel Bright Sources (HerBS) sample, a sample of bright, high-redshift Herschel sources detected in the 616.4deg^2^ Herschel Astrophysical Terahertz Large Area Survey. The HerBS sample contains 209 galaxies, selected with a 500um flux density greater than 80mJy and an estimated redshift greater than 2. The sample consists of a combination of hyperluminous infrared galaxies and lensed ultraluminous infrared galaxies during the epoch of peak cosmic star formation. In this paper, we present Submillimetre Common-User Bolometer Array 2 (SCUBA-2) observations at 850um of 189 galaxies of the HerBS sample, 152 of these sources were detected. We fit a spectral template to the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) and 850um SCUBA-2 flux densities of 22 sources with spectroscopically determined redshifts, using a two-component modified blackbody spectrum as a template. We find a cold- and hot-dust temperature of 21.29^+1.35^_-1.66_ and 45.80^+2.88^_-3.48_K, a cold-to-hot dust mass ratio of 26.62^+5.61^_-6.74_ and a {beta} of 1.83^+0.14^_-0.28_. Thee poor quality of the fit suggests that the sample of galaxies is too diverse to be explained by our simple model. Comparison of our sample to a galaxy evolution model indicates that the fraction of lenses are high. Out of the 152 SCUBA-2 detected galaxies, the model predicts 128.4+/-2.1 of those galaxies to be lensed (84.5 per cent). The SPIRE 500um flux suggests that out of all 209 HerBS sources, we expect 158.1+/-1.7 lensed sources, giving a total lensing fraction of 76 per cent.
1488. Herschel Dwarf Galaxy Survey PACS spectroscopy
ID:
ivo://CDS.VizieR/J/A+A/626/A23
Title:
Herschel Dwarf Galaxy Survey PACS spectroscopy
Short Name:
J/A+A/626/A23
Date:
21 Oct 2021
Publisher:
CDS
Description:
We employ a multiphase approach to model the ISM phases of the galaxies from the Herschel Dwarf Galaxy Survey with the spectral synthesis code Cloudy. We characterize the physical conditions (gas densities, radiation fields, porosity) in those galaxies and investigate correlations with metallicity or star-formation activity. We find that the lower-metallicity galaxies tend to have higher ionization parameters and galaxies with higher specific star-formation rates have higher gas densities. The [CII] emission arises mainly from PDRs and the contribution from the ionized gas phases is small, typically less than 30% of the observed emission. We also find a correlation, with scatter, between metallicity and both the PDR covering factor and the fraction of [CII] from the ionized gas. Overall, the low metal abundances appear to be driving most of the changes in the ISM structure and conditions of these galaxies, and not the high specific star-formation rates. These results demonstrate in a quantitative way the increase of ISM porosity at low metallicity.
1489. Herschel far-IR counterparts of SDSS galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/441/2
Title:
Herschel far-IR counterparts of SDSS galaxies
Short Name:
J/MNRAS/441/2
Date:
21 Oct 2021
Publisher:
CDS
Description:
We study a hundred of galaxies from the spectroscopic Sloan Digital Sky Survey (SDSS) with individual detections in the far-infrared Herschel Photodetector Array Camera and Spectrometer bands (100 or 160um) and in the GALEX far-ultraviolet band up to z~0.4 in the COSMOS and Lockman Hole fields. The galaxies are divided into four spectral and four morphological types. For the star-forming and unclassifiable galaxies, we calculate dust extinctions from the ultraviolet (UV) slope, the H{alpha}/H{beta} ratio and the L_IR_/L_UV_ ratio. There is a tight correlation between the dust extinction and both L_IR_ and metallicity. We calculate SFRtotal and compare it with other star formation rate (SFR) estimates (H{alpha}, UV, SDSS) finding very good agreement between them with smaller dispersions than typical SFR uncertainties. We study the effect of mass and metallicity, finding that it is only significant at high masses for SFRH{alpha}. For the AGN and composite galaxies, we find a tight correlation between SFR and L_IR_({sigma}~0.29), while the dispersion in the SFR-L_UV_ relation is larger ({sigma}~0.57). The galaxies follow the prescriptions of the Fundamental Plane in the M-Z-SFR space.
1490. Herschel FIR spectra of GOALS galaxies
ID:
ivo://CDS.VizieR/J/ApJ/846/32
Title:
Herschel FIR spectra of GOALS galaxies
Short Name:
J/ApJ/846/32
Date:
13 Dec 2021 06:52:25
Publisher:
CDS
Description:
We present an analysis of [OI]_63_, [OIII]_88_, [NII]_122_, and [CII]_158_ far-infrared (FIR) fine-structure line observations obtained with Herschel/PACS, for ~240 local luminous infrared galaxies (LIRGs) in the Great Observatories All-sky LIRG Survey. We find pronounced declines ("deficits") of line-to-FIR continuum emission for [NII]_122_, [OI]_63_, and [CII]_158_ as a function of FIR color and infrared luminosity surface density, {Sigma}_IR_. The median electron density of the ionized gas in LIRGs, based on the [NII]_122_/[NII]_205_ ratio, is n_e_=41cm^-3^. We find that the dispersion in the [CII]_158_ deficit of LIRGs is attributed to a varying fractional contribution of photodissociation regions (PDRs) to the observed [CII]_158_ emission, f([CII]_158_^PDR^)=[CII]_158_^PDR^/[CII]_158_, which increases from ~60% to ~95% in the warmest LIRGs. The [OI]_63_/[CII]_158_^PDR^ ratio is tightly correlated with the PDR gas kinetic temperature in sources where [OI]_63_ is not optically thick or self-absorbed. For each galaxy, we derive the average PDR hydrogen density, n_H_, and intensity of the interstellar radiation field, G, in units of G_0_ and find G/n_H_ ratios of ~0.1-50G_0_.cm^3^, with ULIRGs populating the upper end of the distribution. There is a relation between G/n_H_ and {Sigma}_IR_, showing a critical break at {Sigma}_IR_^*^~5x10^10^L_{sun}_/kpc^2^. Below {Sigma}_IR_^*^, G/n_H_ remains constant, ~0.32G_0_.cm^3^, and variations in {Sigma}_IR_ are driven by the number density of star-forming regions within a galaxy, with no change in their PDR properties. Above {Sigma}_IR_^*^, G/n_H_ increases rapidly with {Sigma}_IR_, signaling a departure from the typical PDR conditions found in normal star-forming galaxies toward more intense/harder radiation fields and compact geometries typical of starbursting sources.

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