DOI:
10.1007/s12036-015-9355-8
IAA authors:
Bensch;Del Olmo;Sulentic;Perea
Authors:
Bensch K., Del Olmo A., Sulentic J., Perea J., Marziani P.
Journal:
Journal of Astrophysics and Astronomy
Abstract:
We present a preliminary analysis of X-ray data of quasars in the context of the 4D eigenvector 1 parameter space (Sulentic et al.2000a, b). 4DE1 serves as a surrogate H-R diagram for representing empirical diversity among quasars and identifying the physical drivers of the diversity. The soft X-ray spectral index (Γsoft) was adopted as one of the key 4DE1 that correlates contrasting extremes in Type 1 properties. 4DE1 motivated the hypothesis of two quasar populations (A and B) divided by L/LEDD≈0.2. Pop. A is a largely radio-quiet population with FWHM Hβ<4000 km/s and often showing a soft X-ray excess. Pop. B is a mix of radio-quiet and a majority of RL quasars shows only a hard X-ray power-law SED. The X-ray separation was based upon earlier ROSAT and ASCA data but we now confirm this dichotomy with large samples of X-ray spectra obtained with XMM-Newton and SWIFT. One popular idea connects the soft excess in Pop. A quasars as a signature of thermal emission from a hot accretion disk in sources radiating close to the Eddington limit. © 2015 Indian Academy of Sciences
URL:
https://ui.adsabs.harvard.edu/#abs/2015JApA...36..467B/abstract