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COSMOSVLBA - COSMOS Field VLBA Observations 1.4-GHz Source Catalog

HEASARC
Archive

Overview

This table contains the results of a project using wide-field Very Long Baseline Interferometry (VLBI) observations at 1.4 GHz of 2,865 known radio sources in the Cosmic Evolution Survey (COSMOS) field, a field which has exceptional multi-wavelength coverage. The main objective of this study is to identify the active galactic nuclei (AGN) in this field. Wide-field VLBI observations were made of all known radio sources in the COSMOS field at 1.4 GHz using the Very Long Baseline Array (VLBA). The authors also collected complementary multiwavelength information from the literature for the VLBA-detected sources.The combination of the number of sources, sensitivity, angular resolution and the area covered by this project are unprecedented. A catalog which contains the VLBI-detected sources is presented, the main purpose of which is to be used as an AGN catalog. the complementary multiwavelength (optical, infrared and X-ray) information of the VLBI-detected sources is also presented.

The authors have detected 468 radio sources, expected to be AGN, with the VLBA. This is, to date, the largest sample assembled of VLBI-detected sources in the sub-mJy regime. They find a detection fraction of 20% +/- 1%, considering only those sources from the input catalog which were in principle detectable with the VLBA (2,361). As a function of the VLA flux density, the detection fraction is higher for higher flux densities, since at high flux densities a source could be detected even if the VLBI core accounts for a small percentage of the total flux density. As a function of redshift, the authors see no evolution of the detection fraction over the redshift range 0.5 < z < 3. In addition, they find that faint radio sources typically have a greater fraction of their radio luminosity in a compact core: ~70% of the sub-mJy sources detected with the VLBA have more than half of their total radio luminosity in a VLBI-scale component, whereas this is true for only ~30% of the sources that are brighter than 10 mJy. This suggests that fainter radio sources differ intrinsically from brighter ones. Across the entire sample, the authors find the predominant morphological classification of the host galaxies of the VLBA-detected sources to be early type (57%), although this varies with redshift and at z > 1.5 they find that spiral galaxies become the most prevalent (48%). The number of detections is high enough to study the faint radio population with statistically significant numbers. The authors demonstrate that wide-field VLBI observations, together with new calibration methods such as multi-source self-calibration and mosaicking, result in information which is difficult or impossible to obtain otherwise.

This table contains 504 entries, including the 468 VLBA-detected sources and, for sources with multiple components, entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Source entries have no suffix in their vlba_source_id, e.g., 'C3293', whereas component entries have a, b, c or d suffixes, e.g., 'C0090a' (and a value of 2 for the multi_cpt_flag parameter).


Catalog Bibcode

2017A&A...607A.132H

References

The faint radio sky: VLBA observations of the COSMOS field.
    Herrera Ruiz N., Middelberg E., Deller A., Norris R.P., Best P.N.,
    Brisken W., Schinnerer E., Smolcic V., Delvecchio I., Momjian E.,
    Bomans D., Scoville N.Z., Carilli C.
    <Astron. Astrophys. 607, A132 (2017)>
    =2017A&A...607A.132H        (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in December 2017 based on CDS Catalog J/A+A/607/A132 files vlba_cat.dat and vlba_mw.dat.

Parameters

Name
The name of the VLBA-detected source, being a J2000.0 position-based source designation created by the HEASARC in the general style recommended by the CDS Dictionary of Nomenclature of Celestial Objects, viz., '[HMD2017] CNNNNa', where the prefix stands for 'Herrera Ruiz, Middelberg, Deller 2017', and 'CNNNNa' is the vlba_source_id parameter value.

Vlba_Source_ID
The VLBA source name used in the reference paper. This table contains 504 entries, including entries for each of the 468 VLBA-detected sources and, for sources with multiple components, additional entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Entries which have no suffixes correspond to sources, e.g., 'C3293', whereas entries which have a, b, c or d suffixes, e.g., 'C0090a', correspond to components.

Cosmosvladp_Name
The name given to the VLA-detected source in Schinnerer et al. (2010, ApJS, 188, 384, available at the HEASARC as the VLACOSMJSC table), e.g., COSMOSVLADP JHHMMSS.ss+DDMMSS.s'.

Int_Vla_Flux
The integrated 1.4-GHz flux density of the VLA-detected source, in mJy (converted by the HEASARC from the µJy units used in the reference paper), taken from Schinnerer et al. (2010, ApJS, 188, 384).

Multi_Cpt_Flag
This flag parameter carries information on the multiplicity of the source, and whether the entry refers to a single or multiple source, or to an individual source component that is based on the VLBA observation, as follows:

           0 = single-component source
           1 = multi-component source
           2 = component of a multi-component source
  
The HEASARC added the values of 2 that identify the 36 entries which are individual components of multi-component sources: these were set to 0 in the original table.

RA
The Right Ascension of the radio source or source component as measured with the VLBA (uniform weighting), in the selected equinox. This was given in J2000.0 coordinates to a precision of 10-6 degrees in the original table.

Dec
The Declination of the radio source or source component as measured with the VLBA (uniform weighting), in the selected equinox. This was given in J2000.0 coordinates to a precision of 10-6 degrees in the original table.

LII
The Galactic Longitude of the radio source or source component.

BII
The Galactic Latitude of the radio source or source component.

RMS_1p4_GHz
The local noise RMS measured in mJy/beam (converted by the HEASARC from the µJy/beam units used in the reference paper) with the VLBA (uniform weighting). #

Flux_1p4_GHz
The peak 1.4-GHz flux density of the radio source or source component, in mJy/beam (converted by the HEASARC from the µJy/beam units used in the reference paper) measured with the VLBA (uniform weighting). This field is left blank for the entries for multiple radio sources (entries with multi_cpt_flag = 1).

Flux_1p4_GHz_Error
The uncertainty in the peak 1.4-GHz flux density of the radio source or source component, in mJy/beam (converted by the HEASARC from the µJy/beam units used in the reference paper) measured with the VLBA (uniform weighting). This field is left blank for the entries for multiple radio sources (entries with multi_cpt_flag = 1).

Int_Flux_1p4_GHz
The integrated 1.4-GHz flux density of the radio source or source component, in mJy (converted by the HEASARC from the µJy units used in the reference paper) measured with the VLBA (uniform weighting). See Section 4 of the reference paper for more details.

Int_Flux_1p4_GHz_Error
The uncertainty in the integrated 1.4-GHz flux density of the radio source or source component, in mJy (converted by the HEASARC from the µJy units used in the reference paper) measured with the VLBA (uniform weighting). See Section 4 of the reference paper for more details.

Phot_Redshift
The photometric redshift of the multiwavelength counterpart within a 1.0-arcsecond radius of the radio source. The photometric redshifts were taken from Capak et al. (2007, ApJS, 172, 99), Baldi et al. (2014, A&A, 567, A76), Salvato et al. (2011, ApJ, 742, 61), Kartaltepe et al.(2010, ApJ, 709, 572), Brusa et al. (2010, ApJ, 716, 348) and Lilly et al. (2007, ApJS, 172, 70).

Redshift
The spectroscopic redshift of the multiwavelength counterpart within a 1.0-arcsecond radius of the radio source. The spectroscopic redshifts were taken from Gabor et al. (2009, ApJ, 691, 705), Trump et al. (2009, ApJ, 696, 1195), Civano et al. (2012, ApJS, 201, 30), Brusa et al. (2010, ApJ, 716, 348), Kartaltepe et al. (2010, ApJ, 721, 98), Lusso et al. (2011, A&A, 534, A110), Lackner et al. (2014, AJ, 148, 137), Ranalli et al. (2012, A&A, 542, A16) and Hao et al.(2014, MNRAS, 438, 1288).

IRAC_3p6_um_Flux
The Spitzer/IRAC 3.6-um flux density of the infrared counterpart within a 1.0-arcsecond radius of the radio source, in µJy. These IR fluxes are taken from Brusa et al. (2010, ApJ, 716, 348) and Civano et al. (2012, ApJS, 201, 30).

MIPS_24_um_Flux
The Spitzer/MIPS 24-um flux density of the infrared counterpart within a 1.0-arcsecond radius of the radio source, in µJy. These IR fluxes are taken from Brusa et al. (2010, ApJ, 716, 348), Kartaltepe et al. (2010, APJ, 709, 572) and the Spitzer Enhanced Imaging Products (SEIP) source list from the NASA/IPAC Infrared Science Archive.

SB_Xray_Flux
The soft-band (0.5-2 keV) flux of the X-ray counterpart within a 1.0-arcsecond radius of the radio source, in erg s-1 cm-2. These X-ray fluxes are taken from Civano et al. (2016, ApJ, 819, 62), Brusa et al. (2010, ApJ, 716, 348), Cappelluti et al. (2009, A&A, 497, 635) and Hasinger et al. (2007, ApJS, 172, 29).

HB_Xray_Flux
The hard-band (2-10 keV) flux of the X-ray counterpart within a 1.0-arcsecond radius of the radio source, in erg s-1 cm-2. These X-ray fluxes are taken from Civano et al. (2016, ApJ, 819, 62), Brusa et al. (2010, ApJ, 716, 348), Cappelluti et al. (2009, A&A, 497, 635) and Hasinger et al. (2007, ApJS, 172, 29).

Morph_Class
The morphological classification of the galaxy within a 1.0-arcsecond radius of the radio source, taken from Tasca et al. (2009, A&A, 503, 379), Baldi et al. (2014, A&A, 567, A76), Salvato et al. (2011, ApJ, 742, 61), Trump et al. (2009, ApJ, 696, 1195), Brusa et al. (2010, ApJ, 716, 348), Gabor et al. (2009, ApJ, 691, 705) and Lusso et al. (2011, A&A, 534, A110). This information is coded as follows:

    1: early type;
    2: spiral;
    3: irregular;
    4: possible merger;
    5: broad emission line object (type 1 AGN);
    6: narrow emission line object (type 2 AGN and star- forming galaxies);
    7: absorption line galaxies;
    8: extended source;
    9: compact source;
   10: normal/star-forming galaxy;
   11: red galaxy;
   12: FRI object;
   13: FRII object.
  

Log_Galaxy_Mass
The stellar mass of the associated galaxy from Baldi et al. (2014, A&A, 567, A76), Kartaltepe et al. (2010, ApJ, 721, 98) and Lusso et al. (2011, A&A, 534, A110), in solar masses.

Log_Black_Hole_Mass
The black hole mass of the AGN from Trump et al. (2011, ApJ, 733, 60) and Hao et al. (2014, MNRAS, 438, 1288), in solar masses.

Class
The HEASARC Browse object classification of the galaxy in which the radio source is situated, based upon the value of the morph_class parameter.


Contact Person

Questions regarding the COSMOSVLBA database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Wednesday, 20-Dec-2017 14:24:27 EST