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GMRTSPXFLS - Giant Metrewave Radio Telescope Spitzer Extragalactic First Look Survey Field 610-MHz Radio Source Catalog

HEASARC
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Overview

This table contains a source catalog based on observations of the Spitzer extragalactic First Look Survey (xFLS) field taken at 610 MHz with the Giant Metre-wave Radio Telescope (GMRT). Seven individual pointings were observed, covering a total area of ~ 4 square degrees with a resolution of 5.8 x 4.7 arcsec2, position angle 60 degrees. The rms noise at the center of the pointings is between 27 and 30 microJansky (uJy) before correction for the GMRT primary beam. The techniques used for data reduction and production of a mosaicked image of the region are described in the reference paper, where the final mosaic, along with a catalog of 3944 sources detected above a ~ 5-sigma threshold, are presented. The survey complements existing radio and infrared data available for this region. For further details of the surveys and data analysis procedures, please refer to the published paper.

This table contains the xFLS catalog of 3944 610-MHz radio sources detected by the GMRT, the 05-May-2008 (Release 1.1) version provided to the CDS by the co-author Sally Hales (MRAO, Cambridge). In this version, a rounding error in the right ascension and declination positions listed for some sources in the original 10-May-2007 (Release 1.0) version has been corrected. The source IAU designations remain unchanged, having been based on the correctly computed positions throughout. The main purpose in correcting the positions was to eliminate sporadic mismatches betweeen IAU designation and listed position in the first data release. In other respects the effect on the positions is negligible.


Catalog Bibcode

2007MNRAS.376.1251G

References

Deep 610-MHz Giant Metrewave Radio Telescope observations of the Spitzer
extragalactic First Look Survey field.
I. Observations, data analysis  and source catalogue.
    Garn T., Green D.A., Hales S.E.G., Riley J.M., Alexander P.
   <Mon. Not. R. Astron. Soc., 376, 1251-1260 (2007)>
   =2007MNRAS.376.1251G

Provenance

This table was created by the HEASARC in February 2012 based on CDS catalog J/MNRAS/376/1251 file gmrtfls.dat, the release 1.1 (05-May-2008) version.

Parameters

Name
The name of the radio source using the IAU-style designation for the source based on the truncated J2000.0 equatorial coordinates of its centroid, viz., 'FLSGMRT JHHMMSS.s+DDMMSS', as registered with the CDS Dictionary of Nomenclature of Celestial Objects, where the FLSGMRT prefix stands for 'First Look Survey Giant Metrewave Radio Telescope'.

RA
The Right Ascension of the source in the selected equinox, calculated using first moments of the relevant pixel brightnesses to give the centroid position. This was given in J2000.0 coordinates to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the source in the selected equinox, calculated using first moments of the relevant pixel brightnesses to give the centroid position. This was given in J2000.0 coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the radio source centroid.

BII
The Galactic Latitude of the radio source centroid.

Flux_610_MHz
The radio brightness of the peak pixel in the 610-MHz radio source, in mJy/beam.

RMS_610_MHz
The local rms noise near the source position, in mJy/beam (converted by the HEASARC from the uJy/beam units used in the original table).

Int_Flux_610_MHz
The integrated flux density of the 610-MHz radio source, in mJy, calculated from the mosaic and applying the flux density correction factor described in Appendix B of the reference paper.

Int_Flux_610_MHz_Error
The error in the integrated flux density of the 610-MHz radio source, in mJy, calculated from the local noise level and the source size, and taking into account the correction factor.

Centroid_X_Pixel
The X pixel coordinate from the mosaic image which was closest to the source centroid.

Centroid_Y_Pixel
The Y pixel coordinate from the mosaic image which was closest to the source centroid.

SExtractor_DB_Flag
The SEXTRACTOR (Source Extractor) deblended object flag, 0 for most (unblended) objects, else coded as follows:

     1 = source has been split up into two or more components
  
There are 211 sources present in the catalog with non-zero deblend flags, and it is necessary to examine the GMRT mosaic image, available at http://www.mrao.cam.ac.uk/surveys/GMRT/FLS/, to distinguish between the case where one extended object has been represented by 2 or more entries, compared to the case where two astronomically different objects are actually present.

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 10-Feb-2012