Browse
this table...

SA57XMM - Selected Area 57 XMM-Newton X-Ray Source Catalog

HEASARC
Archive

Overview

The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z >= 1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead to a different evolutionary behaviour, with a number density peaking at z ~ 2 independently of the intrinsic luminosity, but this result is limited to active nuclei brighter than the host galaxy. A selection based on optical variability can detect low luminosity AGNs (LLAGNs), where the host galaxy light prevents the identification by non-stellar colours. The authors collected X-ray data in a field where there existed an optically-selected sample of "variable galaxies", i.e. variable objects with diffuse appearance, in order to investigate the X-ray and optical properties of the population of AGNs, particularly of low luminosity ones, where the host galaxy is visible. They observed a field of ~ 0.2 deg^2 in the Selected Area 57, for 67 ks with XMM-Newton. They correlated the list of detected X-ray sources with a photographic survey of SA 57, complete to B_J ~ 23 and with the available spectroscopic data. They obtained a catalog of 140 X-ray sources to limiting fluxes of 5 x 10^-16 and 2 x 10^-15 erg/cm^2/s in the 0.5 - 2 keV and 2 - 10 keV bands, respectively, 98 of which are identified in the optical bands. The X-ray detection of part of the variability-selected candidates confirms their AGN nature. Diffuse variable objects populate the low luminosity side of the sample. Only 25/44 optically-selected QSOs are detected in X-rays. 15% of all QSOs in the field have X/O < 0.1. Additional information on the likely optical counterparts of 98 of the X-ray sources is available in the reference paper, e.g., in Table 3.

Catalog Bibcode

2007A&A...469.1211T

References

An X-ray Survey in SA 57 with XMM-Newton.
    Trevese D., Vagnetti F., Puccetti S., Fiore F., Tomei M., Bershady M.A.
   <Astron. Astrophys. 469, 1211 (2007)>
   =2007A&A...469.1211T

Provenance

This table was created by the HEASARC in September 2007 based on CDS table J/A+A/469/1211 file table2.dat.

Description

The authors obtained a 67 ks XMM-Newton pointing of the SA 57 region centered at (RA, Dec) = (13:08:28, +29:23:07) (J2000). The X-ray observations were performed on January 2005. Source detection was performed on co-added PN + MOS1 + MOS2 images accumulated in four energy bands: 0.5 - 10 keV, 0.5 - 2 keV, 2 - 10 keV, and 5 - 10 keV. The source detections and the X-ray photometry were performed using the PWXDetect code (Pillitteri et al. 2006, A&A, 450, 993) based on wavelet transform of the count rate image. The authors adopted a significance level threshold corresponding to a probability of 2 x 10^-5 that a local maximum is generated by a Poisson fluctuation of the background counts. The limiting fluxes in the four bands are approximately: 10^-15, 5 x 10^-16, 2 x 10^-15, and 10^-14 erg/cm^2/s, respectively. The result of this selection is a sample of 140 sources, detected in at least one band.

Parameters

Source_Number
A running X-ray source number in order of increasing J2000.0 Declination which uniquely identifies the X-ray source.

Name
The name for the x-ray source using the 'SA57X' prefix (for Selected Area 57 X-ray source) and the source number, as used in the reference paper.

Source_Flag
This flag parameter is set to the following non-blank values to indicate the following note on specific X-ray source detections:

   c = At the same position an extended source is detected, corresponding to the
       galaxy cluster ZwCl 1305.4+29, not considered in the present analysis
   d = This source is only detected in the 5-10 keV band, with
       flux = 3.48 x 10^-14 erg/cm^2/s
  

RA
The Right Ascension of the X-ray source in the selected equinox. 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 X-ray 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 X-ray source.

BII
The Galactic Latitude of the X-ray source.

Flux
The X-ray flux of the source, in erg/cm^2/s, in the 0.5 - 10 keV band.

Flux_Flag
This flag parameter is set to 'b' to indicate that the object was not detected in the 0.5 - 10 keV band, but that the quoted value was computed using the measured fluxes in other bands.

SB_Flux
The X-ray flux of the source, in erg/cm^2/s, in the 0.5 - 2 keV band.

SB_Flux_Flag
This flag parameter is set to 'b' to indicate that the object was not detected in the 0.5 - 2 keV band, but that the quoted value was computed using the measured fluxes in other bands.

SB_Flux_Limit
This flag parameter is set to '<' to indicate that the corresponding flux is an upper limit, not a detection.

HB_Flux
The X-ray flux of the source, in erg/cm^2/s, in the 2 - 10 keV band.

HB_Flux_Flag
This flag parameter is set to 'b' to indicate that the object was not detected in the 2 - 10 keV band, but that the quoted value was computed using the measured fluxes in other bands.

HB_Flux_Limit
This flag parameter is set to '<' to indicate that the corresponding flux is an upper limit, not a detection.

Opt_Id_Rank
This flag parameter indicates the reliability of the optical counterpart identification, as follows:

        U = none identified
        I = identified
        M = marginal identification
        A = ambiguous identification
  

Contact Person

Questions regarding the SA57XMM database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 20-Sep-2007