KISS Active Galactic Nuclei in the Soft X-Ray Band: Correlation with the [ITAL]ROSAT[/ITAL] All-Sky Survey
| Autor: | John J. Salzer, Edward C. Moran, Samantha L. Stevenson, Vicki L. Sarajedini |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | The Astronomical Journal. 124:3465-3477 |
| ISSN: | 1538-3881 0004-6256 |
| DOI: | 10.1086/344680 |
| Popis: | We present a study of the X-ray properties of a volume-limited sample of optically selected emission-line galaxies. The sample is derived from a correlation between the KPNO International Spectroscopic Survey (KISS), an H-alpha-selected objective-prism survey of AGNs and starbursting galaxies, and the ROSAT All-Sky Survey (RASS). After elimination of all spurious matches, we identify 18 ROSAT-detected X-ray sources within the KISS sample in the 0.1-2.4 keV band. Due to soft X-ray selection effects, the majority of the ROSAT sources are Seyfert 1 galaxies. The majority (54%) of the ROSAT-KISS Seyferts are classified as narrow-line Seyfert 1 objects, a relatively high percentage compared to previous objective-prism-selected Seyfert galaxy samples. We estimate the X-ray luminosities of the ROSAT-detected KISS objects and derive volume emissivities of 6.63 x 10^38 ergs/s/Mpc^3 and 1.45 x 10^38 ergs/s/Mpc^3 for the 30 deg and 43 deg survey strips, respectively. For those KISS AGNs not detected by RASS, we use the median L_X/L_H-alpha ratio derived from a previous study to estimate L_X. The total 0.5-2 keV volume emissivity we predict for the overall KISS AGN sample is sufficient to account for 22.1 +/- 8.9% of the soft X-ray background (XRB), averaged over both survey strips. The KISS AGN sample is made up predominantly of intermediate-luminosity Seyfert 2's and LINERs, which tend to be weak soft X-ray sources. They may, however, represent a much more significant contribution to the hard XRB. |
| Databáze: | OpenAIRE |
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