VLALHN3GHZ - VLA Lockman Hole 3-GHz Radio Source Catalog

Overview

This table is from the second of two papers describing the observations and source catalogs derived from sensitive 3-GHz images of the Lockman Hole North using the Karl G. Jansky Very Large Array (VLA). In their paper, the authors describe the reduction and cataloguing process, which yielded an image with 8-arcsecond resolution and instrumental noise of sigma_n = 1.01 µJy/beam (µJy/beam) rms (before primary beam corrections) and a catalog of 558 sources detected above 5 * sigma_n. The authors also include details of how they estimate source spectral indices across the 2-GHz VLA bandwidth, finding a median index of -0.76 +/- 0.04. Stacking of source spectra reveals a flattening of spectral index with decreasing flux density. In the reference paper, the authors present a source count derived from the catalog. They show a traditional count estimate compared with a completely independent estimate made via a P(D) confusion analysis, and find very good agreement. Cross-matches of the catalog with X-ray, optical, infrared, radio, and redshift catalogs are also presented. The X-ray, optical and infrared data, as well as AGN selection criteria allow them to classify 10% as radio-loud AGN, 28% as radio-quiet AGN, and 58% as star-forming galaxies, with only 4% unclassified.

Observations were made with the VLA in the C configuration at S band, with a frequency range of 2 to 4GHz, with a total of roughly 50 hours of on-source time in 2012.

The HEASARC has converted the radio and IR flux density units from those given in the original table (µJy and µJy/beam) to its standard units for radio flux densities (mJy and mJy/beam).

Catalog Bibcode

2016MNRAS.462.2934V

References

Deep 3-GHz Observations of the Lockman Hole North with the Very Large Array.
II. Catalogue and microJansky source properties.
     Vernstrom T.S., Scott D., Wall J.V., Condon J.J., Cotton W.D.,
     Kellermann K.I., Perley R.A.
    <Mon. Not. R. Astron. Soc. 462, 2934 (2016)>
    =2016MNRAS.462.2934V        (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in April 2017 based on CDS Catalog J/MNRAS/462/2934 files cat3ghz.dat and catcrx.dat.

Parameters

Name
The J2000.0 position-based radio source designation, 'TV16 JHHMMSS.s+DDMMSS', where the prefix stands for T. Vernstrom, the first author. The names in the original CDS tables were malformed and the HEASARC recreated these names using the form recommended by the Dictionary of Nomenclature of Celestial Objects (DNCO), i.e., including leading zeroes and truncating rather than rounding the coordinates. The 'TV16' prefix has not been registered with the DNCO. Based on its standard naming conventions, the DNCO will likely adopt a format of '[VSW2016] VLA JHHMMSS.s+DDMMSS', where the prefix stands for Vernstrom, Scott, Wall 2016, Very Large Array'.

RA
The Right Ascension of the radio source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-2 seconds of time in the original table.

RA_Error
The uncertainty in the Right Ascension of the radio source, in seconds of time.

Dec
The Declination of the radio source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-1 arcseconds in the original table.

Dec_Error
The uncertainty in the Declination of the radio source, in arcseconds.

LII
The Galactic Longitude of the radio source.

BII
The Galactic Latitude of the radio source.

Nu_Eff
The effective frequency (nu_eff) of the radio source, in GHz, based on its position in the wide-band image. Because of the weighting used to combine the individual images, the primary beam of the wide-band image is frequency-dependent, so the effective frequency of the image decreases with radial distance from the pointing center. The radial dependence of the mean frequency is shown in panel (b) of Fig. 2 in the reference paper. Table 3 in this paper provides a summary of the final image properties.

PB_Atten_Factor
The primary-beam attenuation factor at the location of the radio source in the wide-band image.

Flux_3_GHz
The uncorrected, i.e, not corrected for the primary beam attenuation factor, peak flux density of the radio source, in mJy/beam.

SNR_3_GHz
The signal-to-noise ratio (SNR) of the radio source, defined in Section 3.1 and equation (2) of the reference paper.

Int_Flux_3_GHz
The total (integrated) corrected flux density of the radio source, in mJy.

Int_Flux_3_GHz_Error
The uncertainty in the total flux density of the radio source, in mJy.

Source_Flag
The source morphology and size flag, where 0 is a multi-component, non-Gaussian or complex source, 1 is a resolved source, 2 is a partially resolved source, 3 is a possibly resolved source, and 4 is an unresolved source.

Major_Axis_Limit
This flag parameter is set to '<' to indicate that the specified axis of the 2D elliptical Gaussian model was less than 2 sigma greater than the beam size in that direction.

Major_Axis
The beam-convolved, i.e., as-measured, major axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Major_Axis_Error
The uncertainty in the beam-convolved, i.e., as-measured, major axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Major_Axis_De
The deconvolved major axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Major_Axis_De_Error
The uncertainty in the deconvolved major axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Minor_Axis_Limit
This flag parameter is set to '<' to indicate that the specified axis of the 2D elliptical Gaussian model was less than 2 sigma greater than the beam size in that direction.

Minor_Axis
The beam-convolved, i.e., as-measured, minor axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Minor_Axis_Error
The uncertainty in the beam-convolved, i.e., as-measured, minor axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Minor_Axis_De
The deconvolved minor axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Minor_Axis_De_Error
The uncertainty in the deconvolved minor axis size of the 2D elliptical Gaussian model fitted to the radio source, in arcseconds. A null value indicates that the source was not resolved in this dimension.

Position_Angle
The position angle of the 2D elliptical Gaussian model fitted to the radio source after deconvolution, in degrees.

Spectral_Index
The measured spectral index (alpha) of the radio source from 2 to 4 GHz. The 2-GHz bandwidth of the VLA allowed the authors to obtain information on the spectral behavior of the sources, at least for the brighter ones. They first retrieved the flux density values of each source found within the 12% beam-width level at the positions of the fitted peaks in each of the 16 sub-band images. They applied a primary-beam correction to each value, based on the primary beam for each sub-band frequency and source position. They then performed a weighted least squares fit for alpha and the corresponding fitted 3-GHz flux density, with the weights derived from the normalized sub-band weight from the sub-band rms and the primary-beam correction at the source position. Only sources with spectral indices inside the range -2.25 <= alpha <= 2.25 and with sigma(alpha) <= 0.4 were included in the catalog. These criteria leave 140 sources with spectral index estimates.

Spectral_Index_Error
The uncertainty in the spectral index, alpha, defined as ~ 5/SNR (Condon 2015, preprint, arXiv:150205616), where SNR (the snr_3_ghz parameter in this table) is the peak signal-to-noise ratio of the source.

Xray_FB_Flux
The Chandra 0.3-8.0 keV flux of the X-ray counterpart to the radio source (from Wilkes et al. 2009, ApJS, 185, 433), in erg s^-1 cm^-2.

Xray_HB_Flux
The Chandra 2.5-8.0 keV flux of the X-ray counterpart to the radio source (from Wilkes et al. 2009, ApJS, 185, 433), in erg s^-1 cm^-2.

Umag
The u magnitude (AB-type) of the optical counterpart to the radio source from the SDSS DR9 (Ahn et al. 2012, ApJS, 203, 21, CDS Cat. V/139).

Gmag
The g magnitude (AB-type) of the optical counterpart to the radio source from the SDSS DR9 (Ahn et al. 2012, ApJS, 203, 21, CDS Cat. V/139).

Rmag
The r magnitude (AB-type) of the optical counterpart to the radio source from the SDSS DR9 (Ahn et al. 2012, ApJS, 203, 21, CDS Cat. V/139).

Imag
The i magnitude (AB-type) of the optical counterpart to the radio source from the SDSS DR9 (Ahn et al. 2012, ApJS, 203, 21, CDS Cat. V/139).

Zmag
The z magnitude (AB-type) of the optical counterpart to the radio source from the SDSS DR9 (Ahn et al. 2012, ApJS, 203, 21, CDS Cat. V/139).

KPNO_Umag
The KPNO u magnitude (AB-type) of the optical counterpart to the radio source (from Gonzalez-Solares et al. 2011, MNRAS, 416, 927).

KPNO_Gmag
The KPNO g magnitude (AB-type) of the optical counterpart to the radio source (from Gonzalez-Solares et al. 2011, MNRAS, 416, 927).

KPNO_Rmag
The KPNO r magnitude (AB-type) of the optical counterpart to the radio source (from Gonzalez-Solares et al. 2011, MNRAS, 416, 927).

KPNO_Imag
The KPNO i magnitude (AB-type) of the optical counterpart to the radio source (from Gonzalez-Solares et al. 2011, MNRAS, 416, 927).

Jmag
The J magnitude of the infrared counterpart to the radio source from UKIDSS DR9 (Lawrence et al. 2012, CDS Cat. II/314).

Kmag
The K magnitude of the infrared counterpart to the radio source from UKIDSS DR9 (Lawrence et al. 2012, CDS Cat. II/314). There are 32 entries in this table that have K-magnitude values of -1.90 the significance of which is not known to the HEASARC.

SWIRE_3p6_um_Flux
The Spitzer/SWIRE 3.6-um flux of the infrared counterpart to the radio source, in mJy (from Lonsdale et al. 2003, PASP, 115, 897).

SWIRE_4p5_um_Flux
The Spitzer/SWIRE 4.5-um flux of the infrared counterpart to the radio source, in mJy (from Lonsdale et al. 2003, PASP, 115, 897).

SWIRE_5p8_um_Flux
The Spitzer/SWIRE 5.8-um flux of the infrared counterpart to the radio source, in mJy (from Lonsdale et al. 2003, PASP, 115, 897).

SWIRE_8p0_um_Flux
The Spitzer/SWIRE 8.0-um flux of the infrared counterpart to the radio source, in mJy (from Lonsdale et al. 2003, PASP, 115, 897).

SERVS_3p6_um_Flux
The Spitzer/SERVS 3.6-um flux of the infrared counterpart to the radio source, in mJy (from Mauduit et al. 2012, PASP, 124, 714).

SERVS_4p5_um_Flux
The Spitzer/SERVS 4.5-um flux of the infrared counterpart to the radio source, in mJy (from Mauduit et al. 2012, PASP, 124, 714).

MIPS_24_um_Flux
The Spitzer/MIPS 24-um flux of the infrared counterpart to the radio source, in mJy (from Lonsdale et al. 2003, PASP, 115, 897).

HHDR3_250_um_Flux
The Herschel/Hermes DR3 250-um flux of the infrared counterpart to the radio source, in mJy (from Oliver et al. 2012, CDS Cat. VIII/95).

HHDR3_350_um_Flux
The Herschel/Hermes DR3 350-um flux of the infrared counterpart to the radio source, in mJy (from Oliver et al. 2012, CDS Cat. VIII/95).

HHDR3_500_um_Flux
The Herschel/Hermes DR3 500-um flux of the infrared counterpart to the radio source, in mJy (from Oliver et al. 2012, CDS Cat. VIII/95).

Flux_20_cm
The VLA flux density of the 20-cm (1.4-GHz) counterpart (from Owen & Morrison 2008, AJ, 136, 1889), in mJy.

Flux_90_cm
The VLA flux density of the 90-cm (325-MHz) counterpart (from Owen et al. 2009, AJ, 137, 4846), in mJy.

Redshift
The spectroscopic redshift of the source (from Rowan-Robinson et al. 2008, CDS Cat. II/290; Strazzullo et al. 2010, ApJ, 714, 1305).

Phot_Redshift
The photometric redshift of the source (from Rowan-Robinson et al. 2008, CDS Cat. II/290; Strazzullo et al. 2010, ApJ, 714, 1305).

Contact Person

Questions regarding the VLALHN3GHZ database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:36:23 EDT