- ID:
- ivo://CDS.VizieR/II/337
- Title:
- VISTA Variables in the Via Lactea Survey DR1
- Short Name:
- II/337
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VVV survey targets the galactic bulge and a piece of the adjacent plane in Z, Y, J, H, and Ks. The total area of this survey is 520 square degrees and contains 355 open and 33 globular clusters. The VVV is multi-epoch in nature in order to detect a large number of variable objects and will provide > 100 carefully spaced observations for each tile. 5-sigma detection limits are Z=21.9, Y=21.2, J=20.2, H=18.2, Ks=18.1. These will be used to create a 3-dimensional map of the Bulge from well-understood distance indicators such as RR Lyrae stars. Other science drivers include the ages of stellar populations, globular cluster evolution, as well as the stellar initial mass function. The VVV Survey data delivered in this part of ESO Data Release 1 (DR1) includes the VISTA/VIRCAM paw-print and tile images that were acquired until September 30, 2010, and processed by the Cambridge Astronomical Survey Unit (CASU). This VVV_CAT data release contains the single-epoch band-merged (Z,Y,J,H,Ks) catalogues associated with the VVV tile images that have already been released in the part of DR1 identified as VVV in the ESO archive. VVV_CAT contains 269 tile catalogues.
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- ID:
- ivo://CDS.VizieR/J/A+A/602/A1
- Title:
- VLA-COSMOS 3 GHz Large Project
- Short Name:
- J/A+A/602/A1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the VLA-COSMOS 3GHz Large Project based on 384 hours of observations with the Karl G. Jansky Very Large Array (VLA) at 3GHz (10cm) toward the two square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 uJy/beam over the two square degrees at an angular resolution of 0.75". To fully account for the spectral shape and resolution variations across the broad (2GHz) band, we image all data with a multiscale, multifrequency synthesis algorithm. We present a catalog of 10,830 radio sources down to 5{sigma}, out of which 67 are combined from multiple components. Comparing the positions of our 3GHz sources with those from the Very Long Baseline Array (VLBA)-COSMOS survey, we estimate that the astrometry is accurate to 0.01" at the bright end (signal-to-noise ratio, S/N_3GHz_>20). Survival analysis on our data combined with the VLA-COSMOS 1.4GHz Joint Project catalog yields an expected median radio spectral index of {alpha}=-0.7. We compute completeness corrections via Monte Carlo simulations to derive the corrected 3GHz source counts. Our counts are in agreement with previously derived 3GHz counts based on single-pointing (0.087 square degrees) VLA data. In summary, the VLA-COSMOS 3GHz Large Project simultaneously provides the largest and deepest radio continuum survey at high (0.75") angular resolution to date, bridging the gap between last-generation and next-generation surveys.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A2
- Title:
- VLA-COSMOS 3 GHz Large Project. II.
- Short Name:
- J/A+A/602/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the composition of the faint radio population selected from the VLA-COSMOS 3GHz Large Project, a radio continuum survey performed at 10 cm wavelength. The survey covers a 2.6 square degree area with a mean rms of ~2.3uJy/beam, cataloging 10,830 sources above 5sigma, and enclosing the full 2 square degree COSMOS field. By combining these radio data with optical, near-infrared (UltraVISTA), and mid-infrared (Spitzer/IRAC) data, as well as X-ray data (Chandra), we find counterparts to radio sources for ~93% of the total radio sample (in the unmasked areas of the COSMOS field, i.e., those not affected by saturated or bright sources in the optical to NIR bands), reaching out to z~6. We further classify the sources as star forming galaxies or AGN based on various criteria, such as X-ray luminosity, observed MIR color, UV-FIR spectral-energy distribution, rest-frame NUV-optical color corrected for dust extinction, and radio-excess relative to that expected from the hosts' star-formation rate. We separate the AGN into sub-samples dominated by low-to-moderate and moderate-to-high radiative luminosity AGN, candidates for high- redshift analogues to local low- and high-excitation emission line AGN, respectively. We study the fractional contributions of these sub-populations down to radio flux levels of ~11uJy at 3GHz (or ~20uJy at 1.4GHz assuming a spectral index of -0.7). We find that the dominant fraction at 1.4GHz flux densities above ~200uJy is constituted of low-to-moderate radiative luminosity AGN. Below densities of ~100uJy the fraction of star-forming galaxies increases to ~60%, followed by the moderate-to-high radiative luminosity AGN (~20%), and low-to-moderate radiative luminosity AGN (~20%). Based on this observational evidence, we extrapolate the fractions down to sensitivities of the Square Kilometer Array (SKA). Our estimates suggest that at the faint flux limits to be reached by the (Wide, Deep, and UltraDeep) SKA1 surveys, a selection based only on radio flux limits can provide a simple tool to efficiently identify samples highly (>75%) dominated by star-forming galaxies.
2114. VLA-COSMOS survey. II.
- ID:
- ivo://CDS.VizieR/J/ApJS/172/46
- Title:
- VLA-COSMOS survey. II.
- Short Name:
- J/ApJS/172/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The VLA-COSMOS Large Project is described and its scientific objective is discussed. We present a catalog of 3600 radio sources found in the 2deg^2^ COSMOS field at 1.4GHz. The observations in the VLA A and C configuration resulted in a resolution of 1.5"x1.4" and a mean rms noise of ~10.5(15)uJy/beam in the central 1(2)deg^2^. Eighty radio sources are clearly extended consisting of multiple components, and most of them appear to be double-lobed radio galaxies. The astrometry of the catalog has been thoroughly tested, and the uncertainty in the relative and absolute astrometry are 130 and <55mas, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/118/1435
- Title:
- VLA FIRST survey quasar radio emission
- Short Name:
- J/AJ/118/1435
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the most recent (1998) version of the VLA FIRST survey radio catalog, we have searched for radio emission from 1704 quasars taken from the most recent (1993, Cat. <VII/158>) version of the Hewitt & Burbidge quasar catalog. These quasars lie in the roughly 5000 deg2 of sky already covered by the VLA FIRST survey. Our work has resulted in positive detection of radio emission from 389 quasars, of which 69 quasars have been detected for the first time at radio wavelengths. We find no evidence of a correlation between optical and radio luminosities for optically selected quasars. We find indications of a bimodal distribution of radio luminosity, even at a low flux limit of 1 mJy. We show that radio luminosity is a good discriminant between radio-loud and radio-quiet quasar populations, and that it may be inappropriate to make such a division on the basis of the radio-to-optical luminosity ratio. We discuss the dependence of the radio-loud fraction on optical luminosity and redshift.
- ID:
- ivo://CDS.VizieR/J/ApJS/179/114
- Title:
- VLA 1.4GHz survey of E-CDF-S
- Short Name:
- J/ApJS/179/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed the Extended Chandra Deep Field-South (E-CDF-S) using a mosaic of six deep Very Large Array (VLA) pointings at 1.4GHz. In this paper, we present the survey strategy, description of the observations, and the first data release. The observations were performed during June through September of 2007 and included from 15 to 17 "classic" VLA antennas and 6 to 11 that had been retrofitted for the Expanded VLA (EVLA). The first data release consists of a 34.1'x34.1' image and the attendant source catalog. The image achieves an rms sensitivity of 6.4{mu}Jy per 2.8"x1.6" beam in its deepest regions, with a typical sensitivity of 8uJy. The catalog is conservative in that it only lists sources with peak flux densities greater than seven times the local rms noise, yet it still contains 464 sources. Nineteen of these are complex sources consisting of multiple components. Cross matching of the catalog to prior surveys of the E-CDF-S confirms the linearity of the flux density calibration, albeit with a slight possible offset (a few percent) in scale. Improvements to the data reduction and source catalog are ongoing, and we intend to produce a second data release in 2009 January.
- ID:
- ivo://CDS.VizieR/J/ApJS/205/13
- Title:
- VLA 1.4GHz survey of ECDF-S (DR2)
- Short Name:
- J/ApJS/205/13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep radio observations at 1.4GHz for the Extended Chandra Deep Field South were performed in 2007 June through September and presented in a first data release. The survey was made using six separate pointings of the Very Large Array with over 40hr of observation per pointing. In the current paper, we improve on the data reduction to produce a second data release (DR2) mosaic image. This DR2 image covers an area of about a third of a square degree, reaches a best rms sensitivity of 6uJy, and has a typical sensitivity of 7.4uJy per 2.8" by 1.6" beam. We also present a more comprehensive catalog, including sources down to peak flux densities of five or more times the local rms noise along with information on source sizes and relevant pointing data. We discuss in some detail the consideration of whether sources are resolved under the complication of a radio image created as a mosaic of separate pointings each suffering some degree of bandwidth smearing, and the accurate evaluation of the flux densities of such sources. Finally, the radio morphologies and optical/near-IR counterpart identifications are used to identify 17 likely multiple-component sources and arrive at a catalog of 883 radio sources, which is roughly double the number of sources contained in the first data release.
- ID:
- ivo://CDS.VizieR/J/A+A/409/115
- Title:
- VLA imaging of IRAS 1 Jy ULIRG sample
- Short Name:
- J/A+A/409/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the results of a high resolution radio imaging survey of 83 of the 118 ultraluminous infrared galaxies (ULIRGs) in the IRAS 1Jy ULIRG sample (Kim & Sanders, 1998ApJS..119...41K, Veilleux et al., 2002, Cat. <J/ApJS/143/315>). We have observed these ULIRGs at 15-GHz with the Very Large Array (VLA). We find that ~75% of Seyferts (both type 1 and 2) and LINERs have radio nuclei which are compact at our 150mas resolution. The detection rate of HII nuclei is significantly lower (32%); the detections among these are preferentially HII+LINER/Seyfert composite nuclei. Among ULIRGs with multiple optical or near-IR nuclei our observations detected only one (or no) nucleus; in these the radio detection is typically towards the brightest near-IR nucleus. The compactness of the radio sources, the higher detection rates in AGN-type nuclei than HII nuclei, the preferential detection of nuclei with unresolved point sources in the near-IR, the low soft X-ray to nuclear radio luminosity ratio (arguing against thermal emission powering the radio nuclei), and the lack of correlation between radio power and H{alpha} luminosity, all support an origin of the detected radio nuclei in AGN related activity. This result is especially interesting for LINER ULIRGs for which signatures of AGNs have often been ambiguous in other wavebands. Such a high incidence of AGN would provide, for the first time, a large sample in which to study the interplay between AGN, starbursts, and galaxy mergers.
- ID:
- ivo://nasa.heasarc/skyview/vlss
- Title:
- VLA Low-frequency Sky Survey
- Short Name:
- VLSS
- Date:
- 07 Mar 2025
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The VLA Low-Frequency Sky Survey (VLSS) is a 74 MHz continuum survey covering the entire sky north of -30 degrees declination. Using the VLA in BnA and B-configurations, it will map the entire survey region at a resolution of 80" and with an average rms noise of 0.1 Jy/beam. <p> This version include the data from the VLSS redux which increased the coverage region slightly and substantially improved the data reduction. Details are in the Lane et al. (2012) reference. Provenance: <b>VLSS Team: </b>R.A. Perley, J.J. Condon, W.D. Cotton (NRAO); A.S. Cohen, W.M. Lane (NRC/NRL), N.E. Kassim, T.J.W. Lazio (NRL), W.C. Erickson (UMd). This is a service of NASA HEASARC.
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/1477
- Title:
- VLA 352MHz image of the Bootes field. I.
- Short Name:
- J/MNRAS/450/1477
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 324.5MHz image of the NOAO Bootes field that was made using Very Large Array (VLA) P-band observations. The image has a resolution of 5.6"x5.1", a radius of 2.05 degrees and a central noise of ~0.2mJy/beam. Both the resolution and noise of the image are an order of magnitude better than what was previously available at this frequency and will serve as a valuable addition to the already extensive multiwavelength data that are available for this field. The final source catalogue contains 1370 sources and has a median 325 to 1400MHz spectral index of -0.72. Using a radio colour-colour diagram of the unresolved sources in our catalogue, we identify 33 megahertz peaked-spectrum (MPS) sources. Based on the turnover frequency linear size relation for the gigahertz peaked-spectrum (GPS) and compact steep-spectrum (CSS) sources, we expect that the MPS sources that are compact on scales of tens of milliarcseconds should be young radio loud active galactic nuclei at high (z>2) redshifts. Of the 33 MPS sources, we were able to determine redshifts for 24, with an average redshift of 1.3. Given that five of the sources are at z>2, that the four faint sources for which we could not find redshifts are likely at even higher redshifts and that we could only select sources that are compact on a scale of ~5", there is encouraging evidence that the MPS method can be used to search for high-redshift sources.
