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861. VLA A2390 Cluster of Galaxies 1.4-GHz Source Catalog
ID:
ivo://nasa.heasarc/vla23901p4
Title:
VLA A2390 Cluster of Galaxies 1.4-GHz Source Catalog
Short Name:
VLA23901P4
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains the 1.4-GHz source catalog for the field of the cluster of galaxies A2390 as observed with the Very Large Array (VLA). This is one of the deepest radio images of a cluster field ever taken. The image covers an area of 34' x 34' with a synthesized beam of ~1.4" and a noise level of ~5.6 µJy (µJy) near the field center. In the reference paper, the authors construct differential number counts for the central regions (radius < 16') of this cluster, and find that the faint (S<sub>1.4GHz</sub> < 3 mJy) counts of A2390 are roughly consistent with the lowest blank field number counts. Their analyses indicate that the number counts are primarily from field radio galaxies. The authors suggest that the disagreement of their number counts for this cluster with those from a similarly deep observation of A370 that was also presented in the reference paper can be largely attributed to cosmic variance. The authors observed the A2390 cluster field with the VLA in the A configuration for ~31.4hr on-source during 2008 October. The field center is located at 21:53:36 +17:41:52 (J2000). This table was created by the HEASARC in August 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/202/2/">CDS Catalog J/ApJS/202/2/</a> file table2.dat. This file contained 699 entries for sources detected at 1.4 GHz in the A370 field, as well as 524 entries for sources detected at 1.4 GHz in the A2390 field. Only the latter are included in this HEASARC table, while the former can be found in the HEASARC's <a href="vla3701p4.html">VLA3701P4</a> table. This is a service provided by NASA HEASARC .
862. VLA Coma Cluster of Galaxies 1.4-GHz Source Catalog
ID:
ivo://nasa.heasarc/vlacomacat
Title:
VLA Coma Cluster of Galaxies 1.4-GHz Source Catalog
Short Name:
VLACOMACAT
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains results from deep 1.4-GHz Very Large Array (VLA) radio continuum observations of two ~0.5 deg<sup>2</sup> fields in the Coma cluster of galaxies. The two fields, "Coma 1" and "Coma 3", correspond to the cluster core and the southwest infall region, and were selected on account of abundant pre-existing multiwavelength data. In their most sensitive regions, the radio data reach 0.022 mJy (22 µJy) rms per 4.4" beam, sufficient to detect (at 5-sigma) Coma member galaxies with L<sub>1.4GHz</sub> = 1.3 x 10<sup>20</sup> W Hz<sup>-1</sup> (1.3 x 10<sup>27</sup> erg s<sup>-1</sup> Hz<sup>-1</sup>). The full catalog of radio detections at and above a 4.5-sigma significance threshold is presented herein; there are 1030 of these sources which are detected at >= 5 sigma, 628 of which are within the combined Coma 1 and Coma 3 area. The authors also provide optical identifications of the radio sources using data from the Sloan Digital Sky Survey (SDSS). The depth of the radio observations allows them to detect active galactic nuclei in cluster elliptical galaxies with M<sub>r</sub> < -20.5 (AB magnitudes), including radio detections for all cluster ellipticals with M<sub>r</sub> < -21.8. At fainter optical magnitudes (-20.5 < M<sub>r</sub> <~ -19), the radio sources are associated with star-forming galaxies with star formation rates as low as 0.1M_{sun}_ yr<sup>-1</sup>. The VLA observations were performed over five days in 2006 June as program code AM868. On each of the five days, the scheduled time was centered on the transit of Coma. This table was created by the HEASARC in December 2011 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/AJ/137/4436">CDS catalog J/AJ/137/4436</a> files table2.dat ('The Radio Source Catalog') and table3.dat ('Optical Counterparts to the Radio Sources'). It does not include table4.dat ('Rejected Optical Counterparts to the Radio Sources'). This is a service provided by NASA HEASARC .
863. VLA-COSMOS 3-GHz Large Project Multiwavelength Counterparts Catalog
ID:
ivo://nasa.heasarc/vlacosxoid
Title:
VLA-COSMOS 3-GHz Large Project Multiwavelength Counterparts Catalog
Short Name:
VLACOSXOID
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
In the reference paper, the authors study the composition of the faint radio population selected from the VLA-COSMOS 3-GHz 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 ~2.3 µJy/beam (µJy/beam), cataloguing 10,830 sources above 5 sigma, 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), the authors 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 near-IR (NIR) bands, reaching out to z ~ 6. They further classify the sources as star-forming galaxies or AGN based on various criteria, such as X-ray luminosity, observed mid-infrare (MIR) color, UV-far-infrared (FIR) spectral-energy distribution (SED), rest-frame near-ultraviolet (NUV)-optical color corrected for dust extinction, and radio-excess relative to that expected from the the hosts' star-formation rate. The authors separate the AGN into sub-samples dominated by low-to-moderate and moderate-to-high radiative luminosity AGN, i.e., candidates for high-redshift analogs to local low- and high-excitation emission line AGN, respectively. They study the fractional contributions of these sub-populations down to radio flux levels of ~11 uJy at 3 GHz (or ~20 uJy at 1.4 GHz assuming a spectral index of -0.7), and find that the dominant fraction at 1.4 GHz flux densities above ~200 uJy is constituted of low-to-moderate radiative luminosity AGN MLAGN). Below densities of ~100 uJy the fraction of star-forming galaxies (SFG) increases to ~60%, followed by the moderate-to-high radiative luminosity AGN (HLAGN) with ~20%, and MLAGN with ~20%. Based on this observational evidence, the authors extrapolate the fractions down to sensitivities of the Square Kilometer Array (SKA). Their 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. This table contains the full list of 9,161 optical-MIR counterparts collected over the largest unmasked area accessible to each catalog, being 1.77, 1.73, and 2.35 square degrees for COSMOS2015, i-band, and IRAC catalogs, respectively. The catalog lists the counterpart IDs, properties, as well as the individual criteria used in this work to classify these radio sources. The authors note that complete, non-overlapping samples within a well defined, effective area of 1.77 square degrees (COSMOS2015 masked area flag_C15 = 0, can be formed by combining (i) HLAGN, MLAGN, and clean SFG samples, or, alternatively, (ii) the radio-excess and no-radio-excess samples. This table was created by the HEASARC in July 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A2">CDS Catalog J/A+A/602/A2</a> file table1.dat, the VLA-COSMOS 3-GHz Large Project multiwavelength counterpart catalog. This is a service provided by NASA HEASARC .
864. VLA-COSMOS 3-GHz Large Project Source Catalog
ID:
ivo://nasa.heasarc/vlacos3ghz
Title:
VLA-COSMOS 3-GHz Large Project Source Catalog
Short Name:
VLACOS3GHZ
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains some of the results from the VLA-COSMOS 3-GHz Large Project based on 384 hours of observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz (10 cm) toward the 2 square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a median rms of 2.3 µJy (µJy) beam<sup>-1</sup> over the 2 square degrees at an angular resolution of 0.75 arcseconds. To fully account for the spectral shape and resolution variations across the broad (2-GHz) band, the authors imaged all the data with a multiscale, multifrequency synthesis algorithm. In this table, the catalog of 10,830 radio sources down to 5 sigma is presented, out of which 67 are combined from multiple components. Comparing the positions of these 3-GHz sources with those from the Very Long Baseline Array (VLBA)-COSMOS survey, the authors estimate that the astrometry is accurate to 0.01 arcseconds at the bright end (signal-to-noise ratio, S/N<sub>3GHz</sub> > 20). Survival analysis on these data combined with the VLA-COSMOS 1.4-GHz Joint Project catalog yields an expected median radio spectral index alpha = -0.7. The authors compute completeness corrections via Monte Carlo simulations to derive the corrected 3-GHz source counts. Their counts are in agreement with previously derived 3-GHz counts based on single-pointing (0.087 square degrees) VLA data. In summary, the VLA-COSMOS 3-GHz 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. The catalog contains sources selected down to a 5-sigma (where sigma ~2.3 µJy/beam) threshold. This catalog can be used for statistical analyses, accompanied with the corrections given in the data & catalog release paper. All completeness and bias corrections and source counts presented in the paper were calculated using this sample. The total fraction of spurious sources in the COSMOS 2 sq.deg. field is below 2.7% within this catalog. However, an increase of spurious sources up to 24% at 5.0 < S/N < 5.5 is present (for details see Sec. 5.2., Fig. 17 and Table 3 of the reference paper). A subsample with a minimal spurious source fraction can be selected by requiring an additional cutoff S/N >= 5.5 for single component sources (MULTI=0). The total fraction of spurious sources in the COSMOS 2 sq.deg. field within such a selected sample is below 0.4%, and the fraction of spurious sources is below 3% even at the lowest S/N of 5.5. This table was created by the HEASARC in June 2017 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/602/A1">CDS Catalog J/A+A/602/A1</a> file table1.dat, the VLA-COSMOS 3-GHz radio source catalog. This is a service provided by NASA HEASARC .
865. VLA-COSMOS Large Project 1.4-GHz Source Catalog
ID:
ivo://nasa.heasarc/vlacosmos
Title:
VLA-COSMOS Large Project 1.4-GHz Source Catalog
Short Name:
VLACOSMOS
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The international COSMOS (Cosmic Evolution) survey (Scoville et al. 2007, ApJS, 172, 1) is a panchromatic imaging and spectroscopic survey of a 1.4 degree by 1.4 degree field designed to probe galaxy and SMBH (supermassive black hole) evolution as a function of cosmic environment. One major aspect of the COSMOS survey is the Hubble Space Telescope (HST) Treasury Project (Scoville et al. 2007, ApJS, 172, 38), entailing the largest ever allocation of HST telescope time. The equatorial location of the COSMOS field offers the critical advantage of allowing major observatories from both hemispheres to join forces in this endeavor. State-of-the-art imaging data at all wavelengths (X-ray to centimeter, plus large optical spectroscopic campaigns using the VLT VIMOS and the Magellan IMACS instruments (Lilly et al. 2007; Impey et al. 2007; Trump et al. 2007) have been or are currently being obtained for the COSMOS field. These make the COSMOS field an excellent resource for observational cosmology and galaxy evolution in the important redshift range z ~ 0.5 - 3, a time span covering ~ 75% of the lifetime of the universe. The VLA-COSMOS Large Project produced a catalog of 3643 radio sources found in the 2 square degrees COSMOS field at 1.4 GHz with a signal-to-noise threshold S/N >= 4.5. The observations in the VLA A and C configurations resulted in a resolution of 1.5" by 1.4" and a mean rms noise of ~ 10.5 µJy (µJy) beam<sup>-1</sup> in the central 1 deg<sup>2</sup>, and of 15 uJy in the 2 deg<sup>2</sup> field. 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 < 55 mas, respectively. This table was created by the HEASARC in September 2007 based on the electronic version of Table 3 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
866. VLA-COSMOS Project 1.4-GHz Joint Source Catalog
ID:
ivo://nasa.heasarc/vlacosmjsc
Title:
VLA-COSMOS Project 1.4-GHz Joint Source Catalog
Short Name:
VLACOSMJSC
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
In the context of the VLA-COSMOS Deep project, additional VLA A array observations at 1.4 GHz were obtained for the central degree of the COSMOS field and combined with the existing data from the VLA-COSMOS Large project. A newly constructed Deep mosaic with a resolution of 2.5 arcseconds was used to search for sources down to 4 sigma with 1 sigma ~ 12 µJy beam<sup>-1</sup> in the central 50' x 50'. This new catalog is combined with the catalog from the Large project (obtained at 1.5" x 1.4" resolution) to construct a new Joint catalog. All sources listed in the new Joint catalog have peak flux densities of >= 5 sigma at 1.5" and/or 2.5" resolution to account for the fact that a significant fraction of sources at these low flux levels are expected to be slightly resolved at 1.5" resolution. All properties listed in the Joint catalog, such as peak flux density, integrated flux density, and source size, are determined in the 2.5" resolution Deep image. In addition, the Joint catalog contains 43 newly identified multi-component sources. This table was created by the HEASARC in June 2010 based on the electronic version of Table 3 from the reference paper which was obtained from the ApJ web site. This is a service provided by NASA HEASARC .
867. VLA-COSMOS Survey 324-MHz Continuum Source Catalog
ID:
ivo://nasa.heasarc/vlacos324m
Title:
VLA-COSMOS Survey 324-MHz Continuum Source Catalog
Short Name:
VLACOS324M
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains a source catalog based on 90-cm (324-MHz) Very Large Array (VLA) imaging of the COSMOS field, comprising a circular area of 3.14 square degrees centered on 10<sup>h</sup> 00<sup>m</sup> 28.6<sup>s</sup>, _02<sup>o</sup> 12' 21" (J2000.0 RA and Dec). The image from the merger of 3 nights of observations using all 27 VLA antennas had an effective total integration time of ~ 12 hours, an 8.0 arcsecond x 6.0 arcsecond angular resolution, and an average rms of 0.5 mJy beam<sup>-1</sup>. The extracted catalog contains 182 sources (down to 5.5 sigma), 30 of which are multi-component sources. Using Monte Carlo artificial source simulations, the authors derive the completeness of the catalog, and show that their 90-cm source counts agree very well with those from previous studies. In their paper, the authors use X-ray, NUV-NIR and radio COSMOS data to investigate the population mix of this 90-cm radio sample, and find that the sample is dominated by active galactic nuclei. The average 90-20 cm spectral index (S_nu_~ nu<sup>alpha</sup>, where S<sub>nu</sub> is the flux density at frequency nu and alpha the spectral index) of the 90-cm selected sources is -0.70, with an interquartile range from -0.90 to -0.53. Only a few ultra-steep-spectrum sources are present in this sample, consistent with results in the literature for similar fields. These data do not show clear steepening of the spectral index with redshift. Nevertheless, this sample suggests that sources with spectral indices steeper than -1 all lie at z >~ 1, in agreement with the idea that ultra-steep-spectrum radio sources may trace intermediate-redshift galaxies (z >~ 1). Using both the signal and rms maps (see Figs. 1 and 2 in the reference paper) as input data, the authors ran the AIPS task SAD to obtain a catalog of candidate components above a given local signal-to-noise ratio (S/N) threshold. The task SAD was run four times with search S/N levels of 10, 8, 6 and 5, using the resulting residual image each time. They recovered all the radio components with a local S/N > 5.00. Subsequently, all the selected components were visually inspected, in order to check their reliability, especially for the components near strong side-lobes. After a careful analysis, a S/N threshold of 5.50 was adopted as the best compromise between a deep and a reliable catalog. The procedure yielded a total of 246 components with a local S/N > 5.50. More than one component, identified in the 90-cm map sometimes belongs to a single radio source (e.g. large radio galaxies consist of multiple components). Using the 90-cm COSMOS radio map, the authors combined the various components into single sources based on visual inspection. The final catalog (contained in this HEASARC table) lists 182 radio sources, 30 of which have been classified as multiple, i.e. they are better described by more than a single component. Moreover, in order to ensure a more precise classification, all sources identified as multi-component sources have been also double-checked using the 20-cm radio map. The authors found that all the 26 multiple 90-cm radio sources within the 20-cm map have 20-cm counterpart sources already classified as multiple. The authors have made use of the VLA-COSMOS Large and Deep Projects over 2 square degrees, reaching down to an rms of ~15 µJy beam<sup>1</sup> ^ at 1.4 GHz and 1.5 arcsec resolution (Schinnerer et al. 2007, ApJS, 172, 46: the VLACOSMOS table in the HEASARC database). The 90-cm COSMOS radio catalog has, however, been extracted from a larger region of 3.14 square degrees (see Fig. 1 and Section 3.1 of the reference paper). This implies that a certain number of 90-cm sources (48) lie outside the area of the 20-cm COSMOS map used to select the radio catalog. Thus, to identify the 20-cm counterparts of the 90-cm radio sources, the authors used the joint VLA-COSMOS catalog (Schinnerer et al. 2010, ApJS, 188, 384: the VLACOSMJSC table in the HEASARC database) for the 134 sources within the 20-cm VLA-COSMOS area and the VLA- FIRST survey (White et al. 1997, ApJ, 475, 479: the FIRST table in the HEASARC database) for the remaining 48 sources. The 90-cm sources were cross-matched with the 20-cm VLA-COSMOS sources using a search radius of 2.5 arcseconds, while the cross-match with the VLA-FIRST sources has been done using a search radius of 4 arcseconds in order to take into account the larger synthesized beam of the VLA-FIRST survey of ~5 arcseconds. Finally, all the 90 cm - 20 cm associations were visually inspected in order to ensure also the association of the multiple 90-cm radio sources for which the value of the search radius used during the cross-match could be too restrictive. In summary, out of the total of 182 sources in the 90-cm catalog, 168 have counterparts at 20 cm. This table was created by the HEASARC in October 2014 based on an electronic version of Table 1 from the reference paper which was obtained from the COSMOS web site at IRSA, specifically the file vla-cosmos_327_sources_published_version.tbl at <a href="http://irsa.ipac.caltech.edu/data/COSMOS/tables/vla/">http://irsa.ipac.caltech.edu/data/COSMOS/tables/vla/</a>. This is a service provided by NASA HEASARC .
868. VLA ELAIS N1, N2, N3 Fields 20-cm Source Catalog
ID:
ivo://nasa.heasarc/vlaen20cm
Title:
VLA ELAIS N1, N2, N3 Fields 20-cm Source Catalog
Short Name:
VLAEN20CM
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The authors have used the Very Large Array (VLA) in C configuration to carry out a sensitive 20-cm radio survey of regions of the sky that have been surveyed in the far-infrared (FIR) over the wavelength range 5 -200 microns (µm) with ISO (Infrared Space Observatory) as part of the European Large-Area ISO Survey (ELAIS). As usual in surveys based on a relatively small number of overlapping VLA pointings, the flux limit varies over the area surveyed: from a 5-sigma limit of 0.135 mJy over an area of 0.12 deg<sup>2</sup> to 1.15 mJy or better over the whole region covered of 4.22 deg<sup>2</sup>. In their paper, the authors present the complete radio catalog of 867 sources, 428 of which form a complete sample in the flux range 0.2 - 1.0 mJy. These regions of the sky have previously been surveyed to shallower flux limits at 20 cm with the VLA as part of the VLA D-configuration NVSS (full width at half-maximum, FWHM = 45arcseconds) and VLA-B configuration FIRST (FWHM = 5 arcseconds) surveys. This whole survey has a nominal 5-sigma flux limit a factor of 2 below that of the NVSS; 3.4 deg<sup>2</sup> of the survey reaches the nominal flux limit of the FIRST survey and 1.5 deg<sup>2</sup> reaches 0.25 mJy, a factor of 4 below the nominal FIRST survey limit. In addition, this survey is at a resolution intermediate between the two surveys and thus is well suited for a comparison of the reliability and resolution-dependent surface brightness effects that affect interferometric radio surveys. The authors have carried out a detailed comparison of their survey and these two independent surveys in order to assess the reliability and completeness of each. Considering the whole sample, they found that to the 5-sigma nominal limits of 2.3 and 1.0 mJy, respectively, the NVSS and FIRST surveys have a completeness of 96<sup>+2</sup><sub>-3</sub> and 89<sup>+2</sup><sub>-3</sub> % and a reliability of 99<sup>+1</sup><sub>-2</sub> and 94<sup>+2</sup><sub>-2</sub> %. The radio observations were obtained of three ISO ELAIS survey regions in the Northern celestial hemisphere (N1 1610+5430, N2 1636+4115 and N3 1429+3306) (see Table 1 of the reference paper for the details of the fields and the individual pointings). The observations are made with the Very Large Array (VLA) radio telescope at 1.4 GHz (20 cm) in the VLA C configuration (maximum baseline 3.4 km) with an angular resolution (FWHM) of ~15 arcseconds. The aim of these VLA observations was to obtain uniform coverage of the ELAIS regions with an rms noise limit of ~50 microJansky (µJy). This table contains the 921 components of 867 total sources detected at a level of >= 5 sigma (44 of which are multiple component sources as defined in Section 4.3 of the reference paper) over a total area of 4.222 deg<sup>2</sup>. There are also entries describing the properties of the total sources for the 44 multi-component sources (for which the positions have been computed as the flux-weighted average positions of their components), and thus this catalog contains 965 (921 + 44) entries. To filter out the latter, component_id values != 'T' should be selected when searching this table. This table was originally ingested by the HEASARC in August 2012, based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/MNRAS/302/222">CDS Catalog J/MNRAS/302/222</a> file table3.dat. It was last updated in September 2013 to remove a duplicate entry for the source ELAISR J142743+331323. This is a service provided by NASA HEASARC .
869. VLA Extended-Chandra Deep Field-South Classification Catalog
ID:
ivo://nasa.heasarc/vlaecdfscls
Title:
VLA Extended-Chandra Deep Field-South Classification Catalog
Short Name:
VLAECDFSCLS
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
The sub-mJy radio population is a mixture of active systems, that is star-forming galaxies (SFGs) and active galactic nuclei (AGNs). In their paper, the authors study a sample of 883 radio sources detected at 1.4 GHz in a deep Very Large Array (VLA) survey of the Extended Chandra Deep Field-South (E-CDF-S) that reaches a best rms sensitivity of 6 microJansky (µJy). The authors have used a simple scheme to disentangle SFGs, radio-quiet (RQ), and radio-loud (RL) AGNs based on the combination of radio data with Chandra X-ray data and mid-infrared observations from Spitzer. They find that at flux densities between about 30 and 100 uJy, the radio population is dominated by SFGs (~60%) and that RQ AGNs become increasingly important over RL ones below 100 uJy. In the paper, the authors also compare the host galaxy properties of the three classes in terms of morphology, optical colors and stellar masses. Their results show that both SFG and RQ AGN host galaxies have blue colors and late-type morphology while RL AGNs tend to be hosted by massive red galaxies with early-type morphology. This supports the hypothesis that radio emission in SFGs and RQ AGNs mainly comes from the same physical process: star formation in the host galaxy. This table was created by the HEASARC in January 2014 based on the machine-readable version of Table 1 from the reference paper which was obtained from the MNRAS web site. This is a service provided by NASA HEASARC .
870. VLA Extended-Chandra Deep Field-South 1.4-GHz Source Catalog
ID:
ivo://nasa.heasarc/vlaecdfs1p4
Title:
VLA Extended-Chandra Deep Field-South 1.4-GHz Source Catalog
Short Name:
VLAECDFS1P4
Date:
18 Apr 2025
Publisher:
NASA/GSFC HEASARC
Description:
Deep radio observations at 1.4 GHz for the Extended Chandra Deep Field South were performed in 2007 June through September and presented in a first data release (Miller et al. 2008, ApJS, 179, 114). The survey was made using six separate pointings of the Very Large Array with over 40 hr of observation per pointing. In the current study, the authors 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 6 µJy (µJy), and has a typical sensitivity of 7.4 uJy per 2.8" by 1.6" beam. The authors 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. In their paper, they 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 so as to arrive at a catalog of 883 radio sources (and also 49 individual components of the 17 multi-component sources), which is roughly double the number of sources contained in the first data release. In order to cover the full E-CDF-S area at near-uniform sensitivity, the authors pointed the VLA at six separate coordinate locations arranged in a hexagonal grid around the adopted center of the CDF-S, viz. RA, Dec (J2000) 03<sup>h</sup> 32<sup>m</sup> 28.00<sup>s</sup>, -27<sup>o</sup> 48' 30.0". The observations were spread over many days on account of the low declination of the field and typically amounted to 5 hr of time per calendar date. The details of the individual pointings are: <pre> Pointing ID R.A. (J2000) DE. (J2000) rms sensitivity for final image ECDFS 1 03:33:22.25 -27:48:30.0 10.5 uJy ECDFS 2 03:32:55.12 -27:38:03.0 9.4 uJy ECDFS 3 03:32:00.88 -27:38:03.0 9.7 uJy ECDFS 4 03:31:33.75 -27:48:30.0 9.5 uJy ECDFS 5 03:32:00.88 -27:58:57.0 10.0 uJy ECDFS 6 03:32:55.12 -27:58:57.0 9.3 uJy </pre> The images corresponding to the six individual pointings were combined to form the final mosaic image (shown in Figure 1 of the reference paper). This HEASARC table contains the catalog of 883 radio sources (Table 3 in the reference paper) and also the catalog of 49 individual components of the 17 multi-component sources (Table 4 in the reference paper), so that there are a total of 932 entries in the present table. To allow users to easily distinguish these types of entry, the HEASARC created a parameter type_flag which is set to 'S' for the 883 source entries and to 'C' for the 49 component entries. The HEASARC created names for the sources following the standard CDS and IAU recommendations for position-based names and using the prefix of '[MBF2013]' for Miller, Bonzini, Fomalont (2013), the first 3 authors and the date of publication of the reference paper. For the components, we have used the names based on the positions of the parent sources and the suffixes 'A', 'B', etc, in order of increasing J2000.0 RA. Thus, for the multi-component source [MBF2013] J033115.0-275518 which has 3 components, there are 4 entries in this table, one for the entire source, and one for each component, e.g.: <pre> Name | type_flag | RA (J2000.0) Dec (J2000.0) [MBF2013] J033115.0-275518 | S | 03 31 15.04 | -27 55 18.8 [MBF2013] J033115.0-275518 A| C | 03 31 13.99 | -27 55 19.9 [MBF2013] J033115.0-275518 B| C | 03 31 15.06 | -27 55 18.9 [MBF2013] J033115.0-275518 C| C | 03 31 17.05 | -27 55 15.2 </pre> The 17 sources thought to consist of multiple components associated with a single host object are each listed with a single aggregate integrated flux density. Gaussian fits to the individual components associated with these sources are separately listed for their components This table was created by the HEASARC in May 2013 based on <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/ApJS/205/13">CDS Catalog J/ApJS/205/13</a> files table3.dat and table4.dat. This is a service provided by NASA HEASARC .