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VLASDF90CM - VLA SWIRE Deep Field 90-cm Source Catalog

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Overview

This table contains some of the results from the deepest radio continuum surveys to date at a radio wavelength of >~ 1m. The observations were taken with the VLA at 324.5 MHz covering a region of the SWIRE Spitzer Legacy survey, centered at RA and Dec of 10:46:00, +59:01:00 (J2000). The data reduction and analysis are described in the reference paper and a catalog of the sources detected above 5 sigma is presented herein. The authors also discuss the observed angular size distribution for the sample in their paper, and, using their deeper 20-cm survey of the same field (Owen and Morrison 2008, AJ, 136, 1889), they calculate spectral indices for sources detected in both surveys. They report log N-log S counts at 90 cm which show a flattening below 5 mJy. Given the median redshift of the population, z ~ 1, the spectral flattening and the flattening of the log N-log S counts occur at radio luminosities normally associated with AGN rather than with galaxies dominated by star formation.

Observations were made of a single pointing center position (given above), with the VLA in A and C configurations for a total of almost 85 hours on-source between 2006 February and 2007 January. However, due to the ongoing EVLA upgrade, only 22 working antennae were typically avaliable in A and 18 in C. Thus, the total integration time was equivalent to ~ 63 hours in A and even less in C, with correspondingly less u-v coverage.


Catalog Bibcode

2009AJ....137.4846O

References

The deep SWIRE field. II. 90cm continuum observations and 20 cm-90 cm spectra.
    Owen F.N., Morrison G.E., Klimek M.D., Greisen E.W.
   <Astron. J. 137, 4846-4853 (2009)>
   =2009AJ....137.4846O

Provenance

This table was created by the HEASARC in September 2010 based on CDS catalog J/AJ/137/4846/ file table2.dat.

Parameters

Source_Number
The catalog source number. If the source has a number less than 3000, then it was found with an S/N >= 5.0 from 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. Numbers beginning with 12 were measured on a 12" resolution image. If the number begins with 24 then the authors used a 24" resolution image. The lower resolution fits were used when they indicated a significantly larger total flux density for the source in question.

Name
The radio source designation, using the '[OMK2009]' prefix (for Owen, Morrison, Klimek 2009) 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 arcsecs.

Flux_90_cm
The corrected peak flux density of the radio source from the 324.5 MHz map, in mJy/beam. Note that this was given in microJy/beam in the original table.

Int_Flux_90_cm
The corrected total flux density of the radio source at 324.5MHz, in mJy. Note that this was given in microJy in the original table.

Int_Flux_90_cm_Error
The estimated error in the total flux density of the radio source at 324.5MHz, in mJy. Note that this was given in microJy in the original table.

SNR_90_cm
The peak signal-to-noise ratio S/N of the radio source. The error in the peak flux density (flux_90_cm) can be recovered by dividing the value of the peak flux density by S/N.

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. When the minor axis is unresolved, a value of 0 is given for the minor axis size and a one-dimensional Gaussian size is assumed when estimating the total flux density. 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. When the minor axis is unresolved, a value of 0 is given for the minor axis size and a one-dimensional Gaussian size is assumed when estimating the total flux density. 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 VLASDF90CM database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 13-Sep-2010