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SDSSXMMQSO - Sloan Digital Sky Survey (DR5)/XMM-Newton Quasar Survey Catalog

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Overview

This table contains the 5th Data Release Sloan Digital Sky Survey (DR5 SDSS)/XMM-Newton Quasar Survey Catalog. This catalog contains 792 SDSS DR5 quasars with optical spectra that have been observed serendipitously in the X-rays with XMM-Newton. These quasars cover a redshift range of z = 0.11 - 5.41 and a magnitude range of i = 15.3 - 20.7. Substantial numbers of radio-loud (70) and broad absorption line (51) quasars exist within this sample. Significant X-ray detections at >=2 sigma account for 87% of the sample (685 quasars), and 473 quasars are detected at >=6 sigma, sufficient to allow X-ray spectral fits. For detected sources, ~60% have X-ray fluxes between F(2-10 keV) = (1-10) x 10-14 erg cm-2 s-1. The authors fit a single power law, a fixed power law with intrinsic absorption left free to vary, and an absorbed power-law model to all quasars with X-ray signal-to-noise ratio >= 6, resulting in a weighted mean photon index Gamma = 1.91 +/- 0.08, with an intrinsic dispersion sigma(Gamma) = 0.38. For the 55 sources (11.6%) that prefer intrinsic absorption, the authors find a weighted mean N_H = 1.5 +/- 0.3 x 1021 cm-2. They find that Gamma correlates significantly with optical color, Delta(g-i), the optical-to-X-ray spectral index (alpha_ox), and the X-ray luminosity. While the first two correlations can be explained as artifacts of undetected intrinsic absorption, the correlation between Gamma and X-ray luminosity appears to be a real physical correlation, indicating a pivot in the X-ray slope.

Catalog Bibcode

2009ApJS..183...17Y

References

The 5th Data Release Sloan Digital Sky Survey/XMM-Newton Quasar Survey.
     Young, M., Elvis, M., Risaliti, G.
    <Astrophys. J. Suppl., 183, 17-32 (2009)>
    =2009ApJS..183...17Y

Provenance

This table was created by the HEASARC in July 2009 based on electronic versions of Tables 1 and 2 from the paper which were obtained from the Astrophysical Journal web site.

Parameters

Name
The J2000.0 position-based SDSS source designation of the quasar.

RA
The Right Ascension of the quasar in the selected equinox. This was constructed by the HEASARC from the SDSS name, which contains the position in J2000.0 cordinates, with the RA given to a precision of 0.01 seconds of time.

Dec
The Declination of the quasar in the selected equinox. This was constructed by the HEASARC from the SDSS name, which contains the position in J2000.0 cordinates, with the Declination given to a precision of 0.1 arcseconds.

LII
The Galactic Longitude of the quasar.

BII
The Galactic Latitude of the quasar.

XMM_ObsID
The XMM-Newton observation identifier (ObsID) of the observation in which the X-ray measurement of the quasar was made.

Redshift
The SDSS redshift of the quasar.

NH_Gal
The Galactic hydrogen column density in the direction of the source, in atoms cm-2.

SNR
The signal-to-noise ratio of the X-ray source at the position of the quasar.

Exposure
The "live" exposure time of the XMM-Newton observation, in seconds (s), after intervals of flaring high-energy background have been removed.

Off_Axis
The off-axis angle of the X-ray source compared to the nominal pointing direction of the XMM-Newton observation, in arcminutes.

Counts
The net X-ray source counts of the source.

Bck_Counts
The background X-ray counts from a background region that is scaled to the area of the source extraction region.

Radio_Loud_Flag
The radio-loud flag FRL. This is defined using the flux ratio RLP = f_5 GHz_/f_4400 Angstrom > 10 (rest frame; e.g., Kellermann et al. 1989, AJ, 98, 1195). The rest-frame 5-GHz flux density is computed from the observed-frame 1.4 GHz flux density assuming a radio power-law slope of alpha = -0.8, with f_(nu) ~ (nu)(alpha). Radio-quiet sources are flagged as FRL = 0 and radio-loud as FRL = 1. If RLP is an upper-limit and > 10, the radio-loudness is undetermined and FRL = 2.

Bal_Flag
The broad absorption-line (BAL) flag, FBAL. BAL criteria are defined in Shen et al. (2008, ApJ, 677, 858). BAL quasars are flagged with FBAL = 1, non-BAL quasars are flagged with FBAL = 0.

Obs_SB_Flux
The observed-frame X-ray flux in the observed soft (0.5-2 keV) band for the source, in erg cm-2 s-1.

Obs_HB_Flux
The observed-frame X-ray flux in the observed hard (2-10 keV) band for the source, in erg cm-2 s-1.

Rest_Frame_SB_Flux
The rest-frame X-ray flux in the soft (0.5-2 keV) band for the source, in erg cm-2 s-1.

Rest_Frame_HB_Flux
The rest-frame X-ray flux in the hard (2-10 keV) band for the source, in erg cm-2 s-1.

Rest_Frame_SB_Lx
The rest-frame X-ray luminosity of the source in the soft (0.5-2 keV) band, in erg s-1. The X-ray luminosities are computed using a Hubble constant H_0 = 70 km/s/Mpc, Omega_M = 0.3, and Omega_Lambda = 0.7.

Rest_Frame_HB_Lx
The rest-frame X-ray luminosity of the source in the hard (2-10 keV) band, in erg s-1. The X-ray luminosities are computed using a Hubble constant H_0 = 70 km/s/Mpc, Omega_M = 0.3, and Omega_Lambda = 0.7.

OX_Spectral_Index
The optical-to-X-ray spectral index alpha_ox of the source. The alpha_ox value is listed as 9.99 if the fit to the X-ray spectrum did not converge properly, resulting in bad/null X-ray fluxes.

Xray_Fit_Flag
This parameter contains a flag, XF, indicating the X-ray fit. An undetected source is flagged as -1 and upper-limits (1.6-sigma level) on flux and luminosity values are listed. A detected source with S/N < 6 is flagged as 0, and detected flux and luminosity values are listed. For sources with S/N > 6, three models can be applied. If a single power-law model (SPL) is preferred, the flag XF = 1 and the SPL power-law parameters are listed, as well as the 90% upper-limit on intrinsic absorption from the intrinsically absorbed power-law (APL) model. If a fixed power-law (FPL) model with variable N_H is preferred, the flag XF = 2. The best-fit slope from the SPL is listed, as well as the best-fit N_H from the FPL model. If the APL model is preferred, the flag XF = 3, and the APL power-law and absorption parameters are listed.

Spectral_Index
The X-ray photon index for the best-fit model. If the APL model is preferred, then the photon index from that model is quote; otherwise, the photon index is from the SPL model.

Spectral_Index_Neg_Err
The 90% lower error in the X-ray photon index.

Spectral_Index_Pos_Err
The 90% upper error in the X-ray photon index.

NH
The inferred intrinsic X-ray absorption, in atoms cm-2.

NH_Min
The 90%-confidence level lower limit to the intrinsic X-ray absorption, in atoms cm-2.

NH_Max
The 90%-confidence level upper limit to the intrinsic X-ray absorption, in atoms cm-2.

Chi_Squared
The chi-squared value for the best-fit X-ray model.

DoF
The number of degrees of freedom for the best-fit X-ray model.


Contact Person

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

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