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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:20261017T051944Z
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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