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SUMMARY:Studying Quasar accretion discs with massive optical variability s
urveys
DTSTART;VALUE=DATE-TIME:20230627T141500Z
DTEND;VALUE=DATE-TIME:20230627T143000Z
DTSTAMP;VALUE=DATE-TIME:20240227T091537Z
UID:indico-contribution-850@cern.ch
DESCRIPTION:Speakers: Patricia Arévalo (Instituto de Física y Astronomí
a\, Universidad de Valparaíso)\nQuasars optical variability gives us clue
s to understand the accretion disc around supermassive black holes. We can
expect variability properties to correlate with the main physical propert
ies of the accreting black hole\, i.e.\, its mass and accretion rate. It h
as been established that the relative amplitude of optical variability ant
i-correlates with the accretion rate and luminosity.The dependence of the
variance on black hole mass has remained elusive\, and contradicting resul
ts\, including positive\, negative\, or no correlation\, have been reporte
d. In this work\, we show that the key to these contradictions lies in the
timescales of variability studied (e.g.\, the length of the light curves
available). By isolating the variance on different timescales as well as m
ass and accretion rate bins we show that there is indeed a negative correl
ation between black hole mass and variance and that this anti-correlation
is stronger for shorter timescale fluctuations. The behavior can be explai
ned in terms of a universal variability power spectrum for all quasars\, r
esembling a broken power law where the variance is constant at low tempora
l frequencies and then drops continuously for frequencies higher than a ch
aracteristic frequency f_b\, where f_b correlates with the black hole mass
. Furthermore\, to explain all the variance results presented here\, not
only the normalization of this power spectrum must anti-correlate with th
e accretion rate\, but also the shape of the power spectra at short timesc
ales must depend on this parameter as well. In this talk I will present th
e possible interpretations of the dependence of power spectral shape on bo
th parameters as well as the data supporting the results.\n\nhttps://indic
o.unina.it/event/61/contributions/850/
LOCATION:Centro Congressi Federico II Aula Magna
URL:https://indico.unina.it/event/61/contributions/850/
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