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VLASDF20CM - VLA SWIRE Deep Field 20-cm Source Catalog

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Overview

This table contains some of the results from deep radio observations taken with the Very Large Array at a center frequency of 1400 MHz covering a region of the Spitzer Wide-area InfraRed Extragalactic (SWIRE) Survey of the Spitzer Legacy survey, centered at RA and Dec of 10:46:00, +59:01:00 (J2000). The reduction and cataloging of radio sources are described in the reference paper. This table comprises the catalog of the sources detected above 5 sigma. The survey presented is the deepest so far in terms of the radio source density on the sky. Perhaps surprisingly, the sources down to the bottom of the catalog appear to have median angular sizes which are still greater than 1 arcsecond, like their cousins 10-100 times stronger. The shape of the differential log N-log S counts also seems to require a correction for the finite sizes of the sources in order to be self-consistent. If the log N-log S normalization remains constant at the lowest flux densities, there are about six sources per square arcminute at 15 microJy (uJy) at 20 cm. Given the finite-source size this implies that we may reach the natural confusion limit near 1 uJy.

The observations were made with the VLA in A, B, C, and D configurations for a total of almost 140 hr on-source between 2001 December and 2004 January. Since the total time is dominated by the A congiguration, the final image for analysis has a resolution of ~1.6 arcseconds.


Catalog Bibcode

2008AJ....136.1889O

References

The Deep Swire Field. I. 20cm continuum radio observations: a crowded sky.
    Owen F.N., Morrison G.E.
   <Astron. J. 136, 1889-1900 (2008)>
   =2008AJ....136.1889O    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in September 2010 based on CDS catalog J/AJ/136/1889/ file table2.dat.

Parameters

Source_Number
The catalog source number. If the source has a number less than 2000, then it was found in the original list with an S/N >= 5.0 by running the AIPS program SAD on the full resolution image. Sources with numbers >= 10000 were found in lower resolution images or in checks of the residual images.

Name
The radio source designation, using the '[OM2008]' prefix (for Owen and Morrison 2008, AJ, 136, 1889) and the source number, as recommended by the Dictionary Of Nomenclature of Celestial Objects.

RA
The Right Ascension of the radio source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the radio source in the selected equinox. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the radio source.

BII
The Galactic Latitude of the radio source.

RA_Error
The estimated error in the radio source Right Ascension, in seconds of time (s).

Dec_Error
The estimated error in the radio source Declination, in arcseconds.

Flux_20_cm
The observed (uncorrected) peak flux density of the radio source from the 1400 MHz map, in mJy/beam. Note that this was given in microJy/beam in the original table.

Int_Flux_20_cm
The corrected total flux density of the radio source at 1400 MHz, in mJy. Note that this was given in microJy in the original table.

Int_Flux_20_cm_Error
The estimated error in the total flux density of the radio source at 1400 MHz, in mJy. Note that this was given in microJy in the original table.

SNR_20_cm
The peak signal-to-noise ratio S/N of the radio source. The error in the peak flux density (flux_20_cm) can be recovered by dividing the value of the peak flux density by the S/N value (snr_20_cm).

Major_Axis_Limit
This parameter is set to '<' if the source was unresolved based on the results of the AIPS tasks JMFIT or SAD.

Major_Axis
The best-fit deconvolved major axis (FWHM) of the radio source, in arcseconds, or, if the source was unresolved, the upper limit to the angular size of the source. If a resolved two-dimensional Gaussian was the best fit, values of the major and minor axes (FWHM) are given, as well as the position angle of the major axis. Sources with very large sizes, for which only values of the major axes are given, had their sizes and total flux densities estimated directly from the radio images using the AIPS tasks IMVAL and TVSTAT.

Minor_Axis
The best-fit deconvolved minor axis (FWHM) of the radio source, in arcsecond. If a resolved two-dimensional Gaussian was the best fit, values of the major and minor axes (FWHM) are given, as well as the position angle of the major axis. Sources with very large sizes, for which only values of the major axes are given, had their sizes and total flux densities estimated directly from the radio images using the AIPS tasks IMVAl and TVSTAT.

Position_Angle
The best-fit position angle of the major axis of the radio source, if extended, in degrees.


Contact Person

Questions regarding the VLASDF20CM database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 9-Sep-2010