Image of Alice in Wonderland at the Mad Hatter's tea party You are cordially invited to afternoon tea and biscuits wine and chocolate

Astronomy Tea Talks at Caltech

Mondays, Hameetman auditorium (Cahill)
Tea:  4.00pm
Talk: 4.15pm

Organized by:

2009 - 2010 season:
24 May 2010 Iosif Papadakis (U Crete)

'On the X-ray variability of Type 1, radio-quiet Seyferts'

The X-ray variability properties of AGN have been extensively
studied during the past twenty years. Significant progress has
been achieved in the estimation of their X-ray power spectral
density functions (PSDs), which (among other things) can be helpful in
the search for characteristic time scales in these objects.I will
present a review of recent results which have shown that the PSDs
have a -2 power law shape at high frequencies and then, below a
characteristic "break - frequency" it flattens to a slope of -1. The
corresponding "break timescale", increases with increasing black hole
mass, and for a given mass, it decreases with increasing accretion rate.
I will discuss the constrains that these relationships put on the
characteristic time scales associated with the the accretion process
itself, which fuels the emission in these objects. I will also present
evidence which indicate a relationship between the PSD characteristic
time scales and the energy spectral slope in AGN, and I will discuss
possible implications of this relationship.

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Last modified on 20th Jul 2011 by Dominik A. Riechers.  

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