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VLAXL325MH - VLA XMM Large Scale Structure Field 325-MHz Source Catalog

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Overview

The XMM Large Scale Structure survey (XMM-LSS) is an X-ray survey aimed at studying the large scale structure of the Universe. The XMM-LSS field (centered at RA (J2000) = 02h 24m 00.27s, Dec (J2000) = -04o 09' 47.6") is currently being followed up using observations across a wide range of wavelengths, and in their paper the authors present the observational results of a low frequency radio survey of the XMM-LSS field using the Very Large Array at 74 and 325 MHz. This survey will map out the locations of the extragalactic radio sources relative to the large scale structure as traced by the X-ray emission. This is of particular interest because radio galaxies and radio-loud AGN show strong and complex interactions with their small and larger scale environment, and different classes of radio galaxies are suggested to lie at different places with respect to the large scale structure.

For the phase calibration of the radio data, the authors used standard self-calibration at 325 MHz and field-base calibration at 74 MHz. Polyhedron-based imaging as well as mosaicking methods were used at both frequencies. At 74 MHz, the resolution was 30 arcseconds, the median 5-sigma sensitivity was ~ 162 mJy/beam and 666 sources were detected over an area of 132 square degrees. At 325 MHz, the resolution was 6.7 arcseconds, the median 5-sigma sensitivity was 4 mJy/beam, and 847 sources were detected over an area of 15.3 square degrees. At 325 MHz, a region of diffuse radio emission which is a cluster halo or relic candidate was detected.

The observations were conducted using the VLA in July 2003 in the A-configuration (most extended) and in June 2002 in the B-configuration.

This table contains the VLA 325-MHz source list, comprising 605 single sources and 615 components of 237 multiple sources, for a total of 1220 entries. (Notice that, in Section 4.1 of the reference paper, somewhat different numbers are given, i.e., the authors quote 621 single sources and 226 multiple sources). For the multiple sources, each component (A, B, etc.) is listed separately, in order of decreasing brightness.


Catalog Bibcode

2006A&A...456..791T

References

New results from the low-frequency counterpart of the
XMM large scale structure survey.
    Tasse C., Cohen A.S., Roettgering H.J.A., Kassim N.E., Pierre M.,
    Perley R., Best P., Birkinshaw M., Bremer M., Liang H.
   <Astron. Astrophys., 456, 791-800 (2006)>
   =2006A&A...456..791T

Provenance

This table was created by the HEASARC in March 2012 based on CDS Catalog J/A+A/456/791 file tablea1.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., '[TRC2006] JHHMM.m+DDMMc', as recommended by the CDS Dictionary of Nomenclature of Celestial Objects, where the '[TRC2006]' prefix stands for 'Tasse, Cohen, Roettgering 2006' and the suffix 'c' is 'A' for the brightest component, 'B' for the next brightest, and so on.

Detect_2_Freq_Flag
This flag parameter is set to 'Y' to indicate that the source was detected at both 325 MHz and 74 MHz.

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_325_MHz
The total integrated flux density of the radio source at 325 MHz, in mJy. For single sources (source_type = 'S'), this is identical to the values of the flux_325_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_325_mhz_flag = ' ') or by using a pixel-based method adding the flux density in 60" diameter apertures centered at the positions of the invidual Gaussian components (if tot_flux_325_mhz_flag = 'P'). See Section 3.5 of the reference paper for more details.

Tot_Flux_325_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, notice.

Tot_Flux_325_MHz_Flag
This flag parameter 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 3.5 of the reference paper for more details.

Flux_325_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 325 MHz, in mJy, as derived through the Gaussian fitting method.

Flux_325_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 325 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. A value of -1.0 indicates that the position angle could not be estimated.

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 325 MHz (as given here) and 1.4 GHz (the NVSS measurement).


Contact Person

Questions regarding the VLAXL325MH database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 1-Mar-2012