GMRT1HXCSF - Giant Metrewave Radio Telescope 1h XMM/Chandra Survey Fld 610-MHz Source Catalog

Overview

This table contains the results of a deep 610-MHz survey of the 1^hr XMM-Newton/Chandra survey area with the Giant Metre-wave Radio Telescope (GMRT). The resulting maps have a resolution of ~7 arcseconds and an rms noise limit of 60 µJy (µJy). To a 5-sigma detection limit of 300 uJy, the authors detect 223 sources within a survey area of 64 arcminutes in diameter. They compute the 610-MHz source counts and compare them to those measured at other radio wavelengths. The well-known flattening of the Eucidean-normalized 1.4-GHz source counts below ~ 2 mJy, usually explained by a population of starburst galaxies undergoing luminosity evolution, is seen at 610 MHz.

In 2004 August, the 1^hr field (centered at (J2000.0) RA, Dec = 01^h 45^m 27^s, -04^o 34' 42") was observed for approximately 4.5 hours at 610 MHz with the GMRT. Observations were carried out in dual band, spectral line mode, the former to maximize bandwidth and the latter to minimize chromatic aberration. Two sidebands, each of 128 spectral channels of 125 kHz, were centred on 602 and 618 MHz to give a total of 32 MHz bandwidth, with two independent circular polarizations recorded.

Sources were extracted with the AIPS task SAD. A conservative peak flux density detection limit of 5 sigma (i.e. 300 uJy) was used to minimize the number of noise spikes spuriously detected as sources. In the areas surrounding the five brightest sources, detection was performed separately with higher detection thresholds to account for the higher rms noise. Within the 20% power radius of the GMRT primary beam at 610 MHz (32 arcminutes), 213 sources were discovered above a 5-sigma peak flux density detection limit of 300 uJy. In order to determine the success of the SAD source extraction, both the science images and the residual noise maps were carefully inspected. There were eight extended sources where the Gaussian model fit by SAD inadequately described the data: these are marked by source_flag = 'a' in this table. The characteristics of these sources were determined using the AIPS task TVSTAT, and contour plots of them are shown in Fig. 1 of the reference paper. Five of these appear to contain two peaks joined by extended emission, that is, they are double-lobe sources.

Catalog Bibcode

2007MNRAS.378..995M

References

A deep Giant Metre-wave Radio Telescope 610-MHz survey of the 1^H
XMM-Newton/Chandra survey field.
    Moss D., Seymour N., McHardy I.M., Dwelly T., Page M.J., Loaring N.S.
   <Mon. Not. R. Astron. Soc., 378, 995-1006 (2007)>
   =2007MNRAS.378..995M

Provenance

This table was created by the HEASARC in June 2012 based on CDS Catalog J/MNRAS/378/995 file table1.dat.

Parameters

Source_Number
A uniquely identifying number for each radio source in the catalog.

Name
The source designation as given in the CDS Dictionary of Nomenclature of celestial Objects, viz., '[MSM2007b] NNN', where the prefix stands for Moss, Seymour, McHardy 2007 and NNN is the source number.

Source_Flag
There were eight extended sources where the Gaussian model fit by SAD inadequately described the data: these have been given values of source_flag = 'a' in this table. The characteristics of these sources were determined using the AIPS task TVSTAT.

RA
The Right Ascension of the radio source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 seconds of time in the original table.

Dec
The Declination of the radio source in the selected equinox. 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.

BII
The Galactic Latitude of the radio source.

SNR_610_MHz
The Signal-to-Noise (S/N) ratio of the 610-MHz detection.

Flux_610_MHz
The peak flux density S_p of the radio source at 610 MHz, in mJy/beam. The original units for this parameter in the reference paper were µJy/beam. The HEASARC converted them to mJy/beam to conform to its standard unit for radio flux densities.

Int_Flux_610_MHz
The integrated flux density S_tot of the radio source at 610 MHz, in mJy, for those sources which were considered reliably resolved. It is left blank for point sources. The original units for this parameter in the reference paper were uJy. The HEASARC converted them to mJy to conform to its standard unit for radio flux densities.

Int_Flux_610_MHz_Error
The 1-sigma error in the best determination of the flux density, i.e., in S_p for point sources and in S_tot for resolved sources, in mJy. The original units for this parameter in the reference paper were uJy. The HEASARC converted them to mJy to conform to its standard unit for radio flux densities.

Angular_Size
The angular size of the radio source, in arcseconds, (as determined from the deconvolution of the clean beam by SAD, with the exception of the eight extended sources whose flux densities were extracted using TVSTAT, in which case the authors give the distance in arcseconds between the 4-sigma contours along the line of greatest extent) for those sources considered reliably resolved.

Contact Person

Questions regarding the GMRT1HXCSF database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:28:09 EDT