X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion.

Details X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion. X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion.

Sep 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009cfdd.confe.147m&link_type=abstract

Chandra's First Decade of Discovery, Proceedings of the conference held 22-25 September, 2009 in Boston, MA. Edited by Scott Wo

Computer Science

Agn Evolution

Scientific paper

Although the fraction of obscured AGN is found to decrease with luminosity from several studies, a non-negligible population of obscured QSOs is still required by the X-ray background synthesis models. We present a large sample (121 objects) of X-ray selected Type-2 QSOs from the XMM-COSMOS survey: sources with high X-ray luminosity (LX>10^{44} erg s^{-1}) and heavy obscuration (NH>10^{22} cm^{-2}), as derived from a detailed X-ray spectral analysis (see Mainieri et al.,2007, ApJS, 172, 368) of the 1800 X-ray point-like sources in this survey. Few (˜5%) of the Type-2 QSOs are best fitted with a pure reflection model. We have performed optical spectroscopy for ˜ 30% of the sample and for the remaining sources we have derived accurate photometric redshifts. The redshift range covered is wide, 0.30.8).We compare the general properties of the host galaxies with the ongoing accretion in their nuclei. Morphology: using five non-parametric diagnostics (asymmetry, concentration, Gini coefficient, M20, ellipticity) we found that ˜10% of the Type-2 QSOs are in elliptical galaxies, ˜55% in disk galaxies and ˜35% in irregular galaxies. The majority of the irregular hosts can be described as undergoing merger activity or show tidal debris. Stellar masses have been derived from SED fitting to the observed photometry(from 0.3 to 4.5 micron) and star formation rates from the [OII] or Hα line fluxes. The majority (˜75%) of QSO-2 host galaxies have stellar masses above log(Mstar)˜10.5 MSun and have ongoing star formation (˜100 MSun/yr). The value of 10.5 MSun is similar to the characteristic mass for obscured AGN (Kauffmann et al. 2003) and radio-loud AGN (Best et al. 2005) in the SDSS. It is also consistent with the more general result that the fraction of galaxies hosting AGN increases with the stellar mass.

Affiliated with

Also associated with

No associations

Rating

X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and X-ray selected Type-2 QSOs: ongoing star formation and obscured accretion. will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-837753