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GMRTLHCAT2 - Giant Metrewave Radio Telescope Lockman Hole 610-MHz Radio Source Catalog 2

HEASARC
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Overview

This table contains a source catalog based on further observations of the Lockman Hole field, made with the Giant Metrewave Radio Telescope at 610 MHz with an angular resolution of 6 x 5 arcsec2. These complement this group's earlier observations of the central ~ 5 deg2 of the Lockman Hole (Garn et al. 2008, MNRAS, 387, 1037, the HEASARC Browse table GMRTLHCAT) by covering a further ~ 8 deg2 area, with an rms noise down to ~ 80 microJansky/beam (uJy/beam). A catalog of 4934 radio sources in both the inner and outer regions of the Lockman Hole is presented in this table.

The earlier survey had 12 pointings covering ~ 5 square degrees in the center of the Lockman Hole, and herein a further 26 pointings in the outer parts of the Lockman Hole are added, to cover a total of ~ 14 square degrees. To match the earlier survey, the images were made with a resolution of 6" x 5", at a position angle of +45 degrees. The majority of the new pointings have an rms noise of ~80 uJy/beam before the primary beam correction, but the noise in the west - particularly near the very bright source 3C244.1 - is worse.


Catalog Bibcode

2010BASI...38..103G

References

Further GMRT observations of the Lockman Hole at 610 MHz.
    Garn T.S., Green D.A., Riley J.M., Alexander P.
   <Bull. Astron. Soc. India, 38, 103-112 (2010)>
   =2010BASI...38..103G    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in February 2012 based on CDS Catalog J/BASI/38.103 file gmrtlh2.cat.

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., 'GMRTLH JHHMMSS.s+DDMMSS', as registered with the CDS Dictionary of Nomenclature of Celestial Objects, where the GMRTLH prefix stands for 'Giant Metrewave Radio Telescope Lockman Hole'.

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.

Int_Flux_610_MHz_Error
The error in the integrated flux density of the 610-MHz radio source, in mJy.

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 coded as follows:

     1 = where a nearby bright source may be affecting the calculated flux
     2 = where a source has been deblended into two or more components
         from a single initial 'island' of flux
     3 = when both conditions 1 and 2 apply
  
There are 226 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/LH/, 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 GMRTLHCAT2 database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 9-Feb-2012