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741. 31GHz survey of low-frequency radio sources
ID:
ivo://CDS.VizieR/J/ApJ/704/1433
Title:
31GHz survey of low-frequency radio sources
Short Name:
J/ApJ/704/1433
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 100m Robert C. Byrd Green Bank Telescope and the 40m Owens Valley Radio Observatory telescope have been used to conduct a 31GHz survey of 3165 known extragalactic radio sources over 143deg^2^ of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4GHz flux densities of 3-10mJy. The resulting 31GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31GHz spectral indices of these sources, we find a mean 31-1.4GHz flux ratio of 0.110+/-0.003 corresponding to a spectral index of {alpha}=-0.71+/-0.01 (S_{nu}_{prop.to}{nu}^{alpha}^); 9.0%+/-0.8% of sources have {alpha}>-0.5 and 1.2%+/-0.2% have {alpha}>0. By combining this spectral-index distribution with 1.4GHz source counts, we predict 31GHz source counts in the range 1mJy<S_31_<4mJy, N(>S_31_)=(16.7+/-1.7)deg^-2^(S_31_/1mJy)^-0.80+/-0.07^.
742. Giant Radio Galaxies in RACS
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.
743. GLASS. IX. Structural param. from HFF & GLASS
ID:
ivo://CDS.VizieR/J/ApJ/835/254
Title:
GLASS. IX. Structural param. from HFF & GLASS
Short Name:
J/ApJ/835/254
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using deep Hubble Frontier Fields imaging and slitless spectroscopy from the Grism Survey from Space, we study 2200 cluster and 1748 field galaxies at 0.2<=z<=0.7 to determine the impact of environment on galaxy size and structure at stellar masses logM_*_/M_{sun}_>7.8, an unprecedented limit at these redshifts. Based on simple assumptions-r_e_=f(M_*_)-we find no significant differences in half-light radii (r_e_) between equal-mass cluster or field systems. More complex analyses --r_e_=f(M_*_,U-V,n,z,{Sigma})-- reveal local density ({Sigma}) to induce only a 7%+/-3% (95% confidence) reduction in r_e_ beyond what can be accounted for by U-V color, Sersic index (n), and redshift (z) effects. Almost any size difference between galaxies in high- and low-density regions is thus attributable to their different distributions in properties other than environment. Indeed, we find a clear color-r_e_ correlation in low-mass passive cluster galaxies (logM_*_/M_{sun}_<9.8) such that bluer systems have larger radii, with the bluest having sizes consistent with equal-mass star-forming galaxies. We take this as evidence that large-r_e_ low-mass passive cluster galaxies are recently acquired systems that have been environmentally quenched without significant structural transformation (e.g., by ram pressure stripping or starvation). Conversely, ~20% of small-r_e_ low-mass passive cluster galaxies appear to have been in place since z>~3. Given the consistency of the small-r_e_ galaxies' stellar surface densities (and even colors) with those of systems more than ten times as massive, our findings suggest that clusters mark places where galaxy evolution is accelerated for an ancient base population spanning most masses, with late-time additions quenched by environment-specific mechanisms mainly restricted to the lowest masses.
744. GLEAM 72-103: GaLactic and Extragalactic Allsky MWA Survey
ID:
ivo://nasa.heasarc/skyview/gleam1
Title:
GLEAM 72-103: GaLactic and Extragalactic Allsky MWA Survey
Short Name:
GLEAM1
Date:
25 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination 30 degrees at frequencies between 72 and 231 MHz. It was made with the Murchison Widefield Array (MWA) using a drift scan method that makes efficient use of the MWA's very large field-of-view. The survey is described in Wayth et al. (2015) and the <a href="https://www.mwatelescope.org/gleam">website</a> at https://www.mwatelescope.org/gleam. <p> The data presented here are from the first year of GLEAM observing, published in: <ul> <li> Hurley-Walker et al. (2017): 25,000 square degrees of extragalactic sky <li> For et al. (2018): the Large and Small Magellanic Clouds <li> Hurley-Walker et al. (2019c): 8,000 square degrees of the Galactic plane </ul> A region around Centaurus A, a few other small regions described by Hurley-Walker et al. (2017), and the Galactic plane between 180 < l < 345 degrees, are not available. <p> The most sensitive and highest-resolution image is the 170-231MHz image which was used for all source-finding in generating the catalogue. It has a resolution of approximately 2.2 x 2.2/cos (dec + 26.7) arcmin at this frequency. However, due to ionospheric distortions, the final resolution of the survey varies by ~10% over the sky, with a direction-dependent PSF. <p> The <i>SkyView</i> data for the GLEAM surveys was extracted using the team's cutout server, into small (3 degree) raw cutouts over the region covered by the GLEAM survey. These cutouts have somewhat variable size and resolution. The default scale (i.e., pixel size) used for <i>SkyView</i> images is given in the table below. Since the GLEAM cutout server will not create an appropriately sized tile for the Sourth Pole, a larger tile offset from the pole is used. <p> <i>SkyView</i> resamples the cutouts retreived from the GLEAM website into the image geometry requested by the user. Only four wide-band datasets are included. The table below gives the frequency range, central frequency and a typical pixel scale for each of these bands. <table border> <tr><th colspan=5> GLEAM Bands In <i>SkyView</i> </th></tr> <tr><th>Band</th> <th>f<sub>min</sub> (MHz)</th> <th>f<sub>max</sub> (MHz)</th> <th>f<sub>C</sub> (MHz)</tg> <th>Pixel scale (") </th> </tr> <tr> <td> 1 </td><td> 72 </td><td>103 </td><td> 88 </td> <td> 56 </td></tr> <tr> <td> 2 </td><td>103 </td><td>134 </td><td>118 </td> <td> 44 </td></tr> <tr> <td> 3 </td><td>138 </td><td>170 </td><td>155 </td> <td> 34 </td></tr> <tr> <td> 4 </td><td>170 </td><td>231 </td><td>200 </td> <td> 28 </td></tr> </table> These data and 20 narrower bands are available through the team website. <p> To minimize resampling artifacts, this survey defaults to the Lanczos third order resampler. SkyView tracks the size and orientation of the beam as given in each of the tiles and includes the averaged value (i.e., the average of the input images weighted by the output pixels sampled from each input) in the BMAJ, BMIN, and BPA keywords of any result FITS file. Provenance: Source data extracted as cutouts from <a href="http://gleam-vo.icrar.org/gleam_postage/q/form">GLEAM cutout server</a> in March 2020 with updates in July 2020.. This is a service of NASA HEASARC.
745. GLEAM II. Galactic plane
ID:
ivo://CDS.VizieR/VIII/102
Title:
GLEAM II. Galactic plane
Short Name:
VIII/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
This work makes available a further of the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey, covering half of the accessible galactic plane, across 20 frequency bands sampling 72-231MHz, with resolution 4-2arcmin. Unlike previous GLEAM data releases, we used multi-scale CLEAN to better deconvolve large-scale galactic structure. For the galactic longitude ranges 345{deg}<l<67{deg}, 180{deg}<l<240{deg}, we provide a compact source catalogue of 22037 components selected from a 60-MHz bandwidth image centred at 200MHz, with RMS noise ~-10-20mJy/beam and position accuracy better than 2-arcsec. The catalogue has a completeness of 50% at ~120mJy, and a reliability of 99.86%. It covers galactic latitudes 1{deg}<=|b|<=10{deg} towards the galactic centre and |b|<=10{deg} for other regions, and is available from Vizier; images covering |b|<=10{deg} for all longitudes are made available on the GLEAM Virtual Observatory (VO).server and SkyView.
746. GLEAM III. South Galactic Pole
ID:
ivo://CDS.VizieR/VIII/109
Title:
GLEAM III. South Galactic Pole
Short Name:
VIII/109
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the South Galactic Pole (SGP) data release from the GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey. These data combine both years of GLEAM observations at 72-231MHz conducted with the Murchison Widefield Array (MWA) and cover an area of 5,113 deg^2^ centred on the SGP at 20h40m<RA<05h04m and -48{deg}<Dec<-2{deg}. At 216MHz, the typical rms noise is ~5mJy/beam and the angular resolution ~2 arcmin. The source catalogue contains a total of 108851 components above 5{sigma}, of which 77 per cent have measured spectral indices between 72 and 231MHz. Improvements to the data reduction in this release include the use of the GLEAM Extragalactic catalogue as a sky model to calibrate the data, a more efficient and automated algorithm to deconvolve the snapshot images, and a more accurate primary beam model to correct the flux scale. This data release enables more sensitive large-scale studies of extragalactic source populations as well as spectral variability studies on a one-year timescale.
747. GLEAM sources ionospheric position shifts
ID:
ivo://CDS.VizieR/VIII/107
Title:
GLEAM sources ionospheric position shifts
Short Name:
VIII/107
Date:
22 Feb 2022
Publisher:
CDS
Description:
Nearly 200 hours of observing with the Murchison Widefield Array (MWA) radio telescope during the Galactic and Extra-galactic All-sky MWA (GLEAM) survey were used to assemble images of ionospheric structure. These images cover a nearly 50 degree-wide area on the sky at a cadence of 10 minutes over many 5-7 hours-long observing runs. They are generated by tracking the apparent motions of ~200-800 cosmic radio sources caused by changes in the transverse gradient of the ionospheric total electron content. Spectral analysis of these images revealed that the dataset was dominated by three distinct signatures. The first is consistent with field-aligned structures within the topside ionosphere/lower plasmasphere previously imaged with the MWA. The second are structures that are relatively large and aligned nearly east/west. Regional weather data implies that these are preferentially detected when there is a noticeable shear within the sub- tropical jet stream, which passes near the MWA. This suggests that this signature may be related to gravity waves launched by jet stream shear. The final signature is consistent with the properties of so-call electro-buoyancy waves that are known to occur at midlatitudes at night. Detections of these were more common when regional sporadic-E was present, supporting a proposed connection between these waves and polarization electric fields that may arise within sporadic-E. We discuss the implications for future observations with the Square Kilometer Array.
748. GLIMPSE Source Catalog (I + II + 3D)
ID:
ivo://CDS.VizieR/II/293
Title:
GLIMPSE Source Catalog (I + II + 3D)
Short Name:
II/293
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIMPSE), is a survey of Galactic Plane central parts made with the Infrared Array Camera (IRAC) aboard the Spitzer Space Telescope (SST). It covers approximately 220 square degrees, between galactic longitudes +/-65{deg} and +/-1{deg} in galactic latitude (up to 4.2{deg} in the central parts). The four IRAC bands are centered at approximately 3.6, 4.5, 5.8 and 8.0{mu}m. The GLIMPSE combines the 3 surveys: * GLIMPSE-I covers the longitude ranges |l|=10--65{deg} and the latitude range |b|<=1{deg} (Benjamin et al. 2003PASP..115..953B) * GLIMPSE-II covers the longitude range of |l|<=10{deg}, and a latitude range |b|<=1{deg} from |l|=5--10, |b|<=1.5 for |l|=2--5, and |b|<=2{deg} for |l|<=2. GLIMPSE-II coverage excludes the Galactic center region |l|<=1, |b|<=0.75 observed by the GALCEN GO program (PID=3677). * GLIMPSE-3D adds vertical extensions up to |b|=4.2{deg} near the galactic center, and up to |b|=3{deg} in selected other parts of the Galaxy (+/-10, 18.5, 25, 30, and -15 (345){deg}). GLIMPSE-II had two-epoch coverage for a total of three visits on the sky. The observations consisted of two 1.2 second integrations at each position in the first epoch of data taking (September 2005) and a single 1.2 second integration at each position six months later (April 2006). The highly reliable v2.0 GLIMPSEII Catalog (v2.0_GLMIIC) consists of point sources that are detected at least twice in one band and at least once in an adjacent band and a S/N > 5 cut for the band with the two detections. There are also faint and bright flux limits on the Catalog entries. The more complete v2.0 Archive (v2.0_GLMIIA) has less stringent criteria, namely two detections in any bands, those detections having a S/N > 5. The IRAC data were bandmerged with the 2MASS All-Sky Point Source Catalog. See the GLIMPSEII v2.0 Data Products & Data Delivery document for more details. The catalog available from CDS merges the 3 surveys GLIMPSE-I (v2.0), GLIMPSE-II (v2.0), and GLIMPSE-3D; Catalog and Archive records are also merged here. In the regions of overlap between the 3 surveys (e.g. longitude around 10{deg}) preference was given to (1) GLIMPSE-II, as recommended in the GLIMPSE documents of May 2007 (glimpse1_v2.0.pdf) and April 2008 (glimpse2-v2.0.pdf); (2) GLIMPSE-I, and (3) GLIMPSE-3D sources. Sources from different surveys were merged if their position is closer than 0.1arcsec. Documents and a document describing in detail the point source photometry steps, see http://www.astro.wisc.edu/glimpse/docs.html
749. Global 86GHz VLBI survey of compact radio sources
ID:
ivo://CDS.VizieR/J/AJ/136/159
Title:
Global 86GHz VLBI survey of compact radio sources
Short Name:
J/AJ/136/159
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from a large 86GHz global very long baseline interferometry (VLBI) survey of compact radio sources. The main goal of the survey is to increase by factors of 3-5 the total number of objects accessible for future 3mm VLBI imaging. The survey observations reach a baseline sensitivity of 0.1Jy and an image sensitivity of better than 10mJy/beam. A total of 127 compact radio sources have been observed. The observations have yielded images for 109 sources, extending the database of the sources imaged at 86GHz with VLBI observation by a factor of 5, and only six sources have not been detected. The remaining 12 objects have been detected but could not be imaged due to insufficient closure phase information.
750. Globular clusters in the ACS Virgo cluster survey
ID:
ivo://CDS.VizieR/J/ApJS/171/101
Title:
Globular clusters in the ACS Virgo cluster survey
Short Name:
J/ApJS/171/101
Date:
21 Oct 2021
Publisher:
CDS
Description:
We analyze the luminosity function of the globular clusters (GCs) belonging to the early-type galaxies observed in the ACS Virgo Cluster Survey. We have obtained maximum likelihood estimates for a Gaussian representation of the globular cluster luminosity function (GCLF) for 89 galaxies. We have also fit the luminosity functions with an "evolved Schechter function", which is meant to reflect the preferential depletion of low-mass GCs, primarily by evaporation due to two-body relaxation, from an initial Schechter mass function similar to that of young massive clusters in local starbursts and mergers. We find a highly significant trend of the GCLF dispersion {sigma} with galaxy luminosity, in the sense that the GC systems in smaller galaxies have narrower luminosity functions. The GCLF dispersions of our Galaxy and M31 are quantitatively in keeping with this trend, and thus the correlation between {sigma} and galaxy luminosity would seem more fundamental than older notions that the GCLF dispersion depends on Hubble type. We show that this narrowing of the GCLF in a Gaussian description is driven by a steepening of the cluster mass function above the classic turnover mass, as one moves to lower luminosity host galaxies. In a Schechter function description, this is reflected by a steady decrease in the value of the exponential cutoff mass scale. We argue that this behavior at the high-mass end of the GC mass function is most likely a consequence of systematic variations of the initial cluster mass function rather than long-term dynamical evolution.

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