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Seminars

ICCUB SEMINAR – Active galactic nuclei as cosmological probes

ICCUB SEMINAR - Active galactic nuclei as cosmological probes
Start
04-11-2018 15:00
End
04-11-2018
Speaker
Elisabeta Lusso
Affiliation
Durham University
Host
ICCUB - IEEC
Place
DAM Seminar Room (724), 7th floor
Location
UB
ABSTRACT

I will present the latest results on our analysis of the non-linear X-ray to UV relation in a sample of optically selected quasars from the Sloan Digital Sky Survey, cross-matched with the most recent XMM-Newton and Chandra catalogues. I will show that this correlation is not only very tight, but can be potentially even tighter by including a further dependence on the emission line full-width half maximum.
This result imply that the non-linear X-ray to optical-ultraviolet luminosity relation is the manifestation of an ubiquitous physical mechanism, whose details are still unknown, that regulates the energy transfer from the accretion disc to the X-ray emitting corona in quasars. I will discuss what the perspectives of AGN in the context of observational cosmology are. I will introduce a novel technique to test the cosmological model using quasars as “standard candles” by employing the non-linear X-ray to UV relation as an absolute distance indicator.
Contact email
kazushi.iwasawa(a)icc.ub.edu