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GMRTXL240M - Giant Metrewave Radio Telescope XMM Large Scale Structure 240-MHz Source Catalog

HEASARC
Archive

Overview

The low-frequency radio survey of the XMM-Large Scale Structure (XMM-LSS) field centered at RA (J2000) = 2h24m00s, Dec (J2000) = -4009'47" aims to study the connection between the extragalactic radio source populations and their environment as traced by X-ray and optical emission. In their paper, the authors present new radio observations of the XMM-LSS field carried out using the Giant Meterwave Radio Telescope (GMRT) at 240 and 610 MHz. These observations complement the observations presented by Cohen at al. (2003, ApJ, 591, 640; CDS Cat. <J/ApJ/591/640>) and Tasse et al. (2006, A&A, 456, 791; CDS Cat. <J/A+A/456/791>) at 74 and 325 MHz with the Very Large Array (VLA). At 240 and 610 MHz, the authors reach noise levels of ~2.5 and ~0.3 mJy/beam, leading to the detection of 466 and 769 sources over 18.0 and 12.7 degree2 with resolutions of 14.7 arcseconds and 6.5 arcseconds, respectively. Combining these data with the available source lists at 74 MHz, 325 MHz (Tasse et al., 2006) and 1400MHz (NVSS), the authors built a multifrequency catalog containing 1611 radio sources. They checked for consistency of the astrometry and flux density estimates. They fit a simple synchrotron radiation model to the flux density measurements of the 318 radio sources that were detected in at least 4 bands. While ~26% of them showed signature of spectral ageing, ~6% showed self absorption.

This table contains the GMRT 240-MHz source list, comprising 388 single sources and 183 components of multiple sources, for a total of 571 entries. For the multiple sources, each component (A, B, etc.) is listed separately, in order of decreasing brightness.


Catalog Bibcode

2007A&A...471.1105T

References

GMRT observations of the XMM Large Scale Structure Survey field.
    Tasse C., Roettgering H.J.A., Best P.N., Cohen A.S., Pierre M., Wilman R.
   <Astron. Astrophys. 471, 1105 (2007)>
   =2007A&A...471.1105T

Provenance

This table was created by the HEASARC in February 2012 based on CS Catalog J/A+A/471/1105 file table3.dat.

Parameters

Name
The name of the radio source constructed by the HEASARC using the IAU-style designation for the source based on its truncated J2000.0 equatorial coordinates, viz., '[TRB2007] JHHMMSS.s+DDMMSSAc', as recommended by the CDS Dictionary of Nomenclature of Celestial Objects, where the '[TRB2007]' prefix stands for 'Tasse, Roettgering, Best 2007' and the suffix 'c' is 'A' for the brightest component, 'B' for the next brightest, and so on.

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

RA_Error
The rms uncertainty in the Right Ascension of the radio source or component, in arcseconds.

Dec
The Declination of the radio source or component in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.01 arcseconds in the original table.

Dec_Error
The rms uncertainty in the Declination of the radio source or component, in arcseconds.

LII
The Galactic Longitude of the radio source or component.

BII
The Galactic Latitude of the radio source or component.

Source_Type
This flag parameter has values of 'S' for single sources with no other associated components, 'M' for the brightest components of multiple sources, and 'C' for the other fainter components of multiple sources.

Tot_Flux_240_MHz
The total integrated flux density of the radio source at 240 MHz, in mJy. For single sources (source_type = 'S'), this is identical to the values of the flux_240_mhz parameter; for multiple sources this field is populated only for the entry corresponding to the brightest ('A') component (source_type = 'M') and corresponds to the integrated flux density of the entire source, calculated either from the sum of the individual Gaussian components (if tot_flux_240_mhz_flag = ' ') or by summing the pixel values in 60" diameter apertures centered at the positions of the invidual Gaussian components (if tot_flux_240_mhz_flag = 'P'). See Section 4.2 of the reference paper for more details.

Tot_Flux_240_MHz_Error
The rms uncertainty in the total integrated flux density of the radio source, in mJy. The error bars associated with the pixel-based total flux density estimates are much bigger than those associated with the Gaussian fitting method because the former does not use any a priori knowledge of the restoring beam shape.

Tot_Flux_240_MHz_Flag
This flag parmater is set to ' ' if the total flux density was calculated from the sum of the individual Gaussian components, or to 'P' if it was calculated by summing the pixel values in 60" diameter apertures centered at the positions of the invidual Gaussian components. See Section 4.2 of the reference paper for more details.

Flux_240_MHz
The integrated flux density of the Gaussian fit to the radio source, if single, or of the individual Gaussian fitting component, if multiple, at 240 MHz, in mJy.

Flux_240_MHz_Error
The rms uncertainty in the integrated flux density of the Gaussian fit to the radio source, if single, or of the individual Gaussian fitting component, if multiple, at 240 MHz, in mJy.

Major_Axis_Limit
This flag parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual measured value.

Major_Axis
The deconvolved size of the fitted Gaussian major axis to the radio source, or the 2-sigma upper limit thereof if the source is unresolved, in arcseconds.

Major_Axis_Error
The rms uncertainty in the deconvolved size of the fitted Gaussian major axis to the radio source, in arcseconds.

Minor_Axis_Limit
This flag parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual measured value.

Minor_Axis
The deconvolved size of the fitted Gaussian minor axis to the radio source, or the 2-sigma upper limit thereof if the source is unresolved, in arcseconds.

Minor_Axis_Error
The rms uncertainty in the deconvolved size of the fitted Gaussian minor axis to the radio source, in arcseconds.

Position_Angle
The position angle of the major axis of the fitted Gaussian component to the radio source, in degrees.

Position_Angle_Error
The rms uncertainty in the position angle of the major axis of the fitted Gaussian component to the radio source, in degrees.

Spectral_Index_Limit
This flag parameter is set to '<' if the corresponding parameter value is an upper limit rather than an actual measured value.

Spectral_Index
The spectral index of the radio source between 240 MHz as given here and 1.4 GHz (the NVSS measurement).


Contact Person

Questions regarding the GMRTXL240M database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 28-Feb-2012