Centrum Astronomii
Uniwersytet Mikołaja Kopernika

Arcsecond scale radio properties of broad absorption line quasars

dr Takayuki HAYASHI, The University of Tokyo / National Astronomical Observatory of Japan

Broad Absorption Line (BAL) quasars have broad resonance line at rest UV spectra. Because of its large velocity, the absorber is considered to be accretion disk wind. ~15% of SDSS quasars show BAL. What does this fraction mean? Covering factor of the wind or the population of quasars? To answer this question, radio observation is one of effective way. Today, I would like to present our recent statistical study for radio-bright BAL quasars. The main topic are as below:
(i) BAL quasars have fainter radio emission than non-BAL quasars. I made Monte-Carlo simulation to test whether or not it can be explained by relativistic Doppler beaming. As a result, I found the faint flux density is attributed to the intrinsic difference of the central
engine.
(ii) Previous studies report that the number of FR-II radio sources in BAL quasars is roughly 10 times less common than that in all SDSS quasars. However, some paper suggest there are no difference of radio morphology. To test whether or not there are the morphological difference I have constructed catalog of FR-II radio source using new SDSS and FIRST data. I found the 10-times difference could be caused by statistical bias but there are still 2 times less number of FR-II BAL quasars than FR-II non-BAL quasars. The result suggest the intrinsic difference between BAL and non-BAL quasars.

Data
25.03.2013 - 11:15
Miejsce
Sala seminaryjna KRA