SEARCH FOR OPTICALLY QUIET QUASARS

Citation
Ri. Kollgaard et al., SEARCH FOR OPTICALLY QUIET QUASARS, The Astrophysical journal, 449(1), 1995, pp. 61-73
Citations number
74
Categorie Soggetti
Astronomy & Astrophysics
Journal title
ISSN journal
0004637X
Volume
449
Issue
1
Year of publication
1995
Part
1
Pages
61 - 73
Database
ISI
SICI code
0004-637X(1995)449:1<61:SFOQQ>2.0.ZU;2-U
Abstract
Optically quiet quasars (OQQs) are compact radio-loud and X-ray-bright active galactic nuclei with very weak optical continuum emission. Sev eral explanations have been proposed for the inverted spectral energy distribution (SED) of OQQs, the most likely being reddening and soft X -ray absorption in excess of that expected from the Galaxy. We have ma de multifrequency observations of three previously known OQQs. The The X-ray spectra are consistent with excess absorption, although we cann ot rule out alternative explanations. The wide range of radio and opti cal properties in these sources suggests that, if excess absorption is important, it arises from a physically unrelated system that intercep ts the line of sight. We also observed 10 OQQ candidates selected from two correlations of the ROSAT All-Sky Survey (RASS) with radio survey s. No clear examples of new OQQs were found.