J/ApJ/434/54 J/ApJ/434/54 Spectral properties of X-ray-selected AGNs R J Thompson F A Cordova Astrophys. J. 434 54 1994 1994ApJ...434...54T Active gal. nuclei X-ray sources galaxies: active X-rays: galaxies We survey the broadband spectral properties of ~500 X-ray-selected active galactic nuclei (AGNs) observed with the Einstein Observatory. Included in this survey are the ~450 AGNs in the Extended Medium Sensitivity Survey of Gioia et al. (1990ApJS...72..567G) and the ~50 AGNs in the Ultrasoft Survey of Cordova et al. (1992ApJS...81..661C). We present a revised version of the latter sample, based on the post publication discovery of a software error in the Einstein Rev-1b processing. We find that the mean spectral index of the AGNs between 0.1 and 0.6keV is softer, and the distribution of indices wider, than previous estimates based on analyses of the X-ray spectra of optically selected AGNs. A subset of these AGNs exhibit flux variability, some on timescales as short as 0.05-days. A correlation between radio and hard X-ray luminosity is confirmed, but the data do not support a correlation between the radio and soft X-ray luminosities, or between radio loudness and soft X-ray spectral slope. Evidence for physically distinct soft and hard X-ray components is found, along with the possibility of a bias in previous optically selected samples toward selection of AGNs with flatter X-ray spectra.

Name Source name --- n_Seq Note number=1 *: source that satisfy our criteria for being "truly" soft, i.e. being free from shadowing by the detector support ribs and having good counting statistics (R1 +1{sigma}<0.6) --- Seq IPC sequence --- SRC Source number --- RAXh X-ray right ascension (1950) h RAXm X-ray right ascension (1950) min RAXs X-ray right ascension (1950) s DEX- X-ray declination sign --- DEXd X-ray declination (1950) deg DEXm X-ray declination (1950) arcmin DEXs X-ray declination (1950) arcsec RAh Optical right ascension (1950) h RAm Optical right ascension (1950) min RAs Optical right ascension (1950) s DE- Optical declination sign --- DEd Optical declination (1950) deg DEm Optical declination (1950) arcmin DEs Optical declination (1950) arcsec z Redshift --- Vmag V magnitude mag NH Hydrogen column density 10+20cm-2 RECO IPC RECO value number=2 Measure of the amount of shadowing by the detector support ribs, Harnden et al., 1984, Smithsonian Astrophys. Obs. Spec. Rep. No. 393 --- Dits Off-axis distance arcmin Name Source name, as in table1a --- R1 Counts in colour ratio R1 --- e_R1 rms uncertainty on R1 --- R2 Counts in colour ratio R2 (C3/C2) --- e_R2 rms uncertainty on R2 --- C1 Counts ratio at the energy band C1=0.16-0.56keV --- e_C1 rms uncertainty on C1 --- C2 Counts ratio at the energy band C2=0.56-1.08keV --- e_C2 rms uncertainty on C2 --- C3 Counts ratio at the energy band C3=1.08-3.5keV --- e_C3 rms uncertainty on C3 --- Name Source name, as in table1a --- IPC IPC counts ct/s e_IPC rms uncertainty on IPC ct/s L1s Soft-component luminosity for the 10eV rest-frame model solLum L2s Soft-component luminosity for the 7.85eV observed-frame model solLum l_Lh Limit flag on Lh --- Lh Hard-component luminosity from the observer-frame model solLum L0.2keV Monochromatic 0.2keV luminosity solLum l_L2.0keV Limit flag on L2.0keV --- L2.0keV Monochromatic 2.0keV luminosity solLum James Marcout, Patricia Bauer CDS 1997Jun06 UNKNOWN UNKNOWN Prepared via OCR at CDS. J_ApJ_434_54.xml