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SUMMARY:Probing Accretion Disk Structure with Long Lags in AGN Photometry
DTSTART;VALUE=DATE-TIME:20230626T094500Z
DTEND;VALUE=DATE-TIME:20230626T100000Z
DTSTAMP;VALUE=DATE-TIME:20260306T075403Z
UID:indico-contribution-860@cern.ch
DESCRIPTION:Speakers: Amy Secunda (Princeton University)\nI will discuss t
 he use of longer timescale “negative” lags\, where the variability in 
 high frequency bands lags the corresponding variability at low frequency\,
  as a probe of accretion disk structure. Traditional reverberation mapping
  uses lags of variations in AGN photometry from high frequency to low freq
 uency wavebands on the light-crossing timescale which come from the reproc
 essing of light in different temperature regions of the disk. The long neg
 ative lag\, on the other hand\, is due to fluctuations in the outer part o
 f the UV/optical region of the disk that are accreted inward on the inflow
  timescale. Because the inflow rate also depends on disk properties\, unli
 ke the speed of light\, these long lags can provide additional information
  about disk structure. Standard disk models predict the inflow timescale i
 s on the order of hundreds of years. However\, recent 3D radiation magneto
 hydrodynamic simulations of AGN disks and analysis of high-cadence\, long 
 baseline observations of Fairall 9 suggest that in the UV/optical region o
 f the disk\, the inflow timescale can be on the order of only 100 days\, n
 ot years. This much shorter lag timescale would make the detection of long
  lags possible with long baseline observations from instruments such as SW
 IFT or Vera C. Rubin Observatory. I will outline the underlying theory of 
 these long lags\, show results from 3D radiation magnetohydrodynamic simul
 ations of disk models beyond the standard disk model\, and also present so
 me candidate long lags.\n\nhttps://indico.unina.it/event/61/contributions/
 860/
LOCATION:Centro Congressi Federico II Aula Magna
URL:https://indico.unina.it/event/61/contributions/860/
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