SIMBAD references

2003ApJS..148..275A - Astrophys. J., Suppl. Ser., 148, 275-315 (2003/October-0)

Optical identification of the ASCA medium sensitivity survey in the northern sky: nature of hard X-Ray-Selected luminous active galactic nuclei.


Abstract (from CDS):

We present the results of optical spectroscopic identifications of a bright subsample of 2-10 keV hard X-ray-selected sources from the ASCA Medium Sensitivity Survey in the northern sky (AMSSn). The flux limit of the subsample is 3x10–13 erg/s/cm2 in the 2-10 keV band. All but one of the 87 hard X-ray-selected sources are optically identified, with AGNs (including broad-line AGNs, narrow-line AGNs, and three BL Lac objects), seven clusters of galaxies, and one galactic star. It is the largest complete sample of hard X-ray-selected AGNs at the bright flux limit. Amounts of absorption to their nuclei are estimated to be hydrogen column densities (NH) of up to ∼3x1023 cm–2 from their X-ray spectra. Optical properties of X-ray absorbed AGNs with NH>1x1022 cm–2 indicate the effects of dust absorption: at redshifts z<0.6, AGNs without broad Hβ emission lines have significantly larger NH-values than AGNs with broad Hβ emission lines. At z>0.6, the X-ray absorbed AGNs have a large hard X-ray to optical flux ratio (logf2–10keV/fR>+1). However, three X-ray absorbed z>0.6 AGNs show strong broad lines. In combination with hard X-ray-selected AGN samples from the ASCA Large Sky Survey, the ASCA Deep Survey in the Lockman Hole, and Chandra Deep Field North, the luminosity distributions of absorbed (NH>1x1022 cm–2) and less-absorbed (NH<1x1022 cm–2) AGNs are compared.

Abstract Copyright:

Journal keyword(s): Cosmology: Diffuse Radiation - Galaxies: Active - Galaxies: Quasars: General - Surveys - X-Rays: Diffuse Background

VizieR on-line data: <Available at CDS (J/ApJS/148/275): table1.dat table2.dat table3.dat table4.dat>

Nomenclature: Table 1: [AUO2003] N=132.

CDS comments: Table 1, col(2): Identification number AANN (AA = NO, NE, SE) represents the number of a source in three source lists used during the optical identification observations, not used in SIMBAD.

Simbad objects: 130

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