14 March 2019
Europe/Warsaw timezone

Wavelength-dependent time delays in AGN accretion discs

14 Mar 2019, 12:20


Ms Aleksandra Olejak (CFT PAN)


The idea of measuring and using wavelength-dependent time delays between
the optical continuum at different EM wavelengths in order to determine AGN
accretion disk structure has been known for many years. For example Sergeev et
al. (2005) modelled the lag-luminosity relation with a disc reprocessing model,
where time delays were caused by different light travel times from the ionizing
source and regions of continuum emission. Collier et al. (1999) gave an idea how
AGNs can be used in cosmology as standard candles by measuring the flux and
the time delays between the optical/UV continuum in an accretion disc. Right
now scientists, for example Cackett et al. 2007 fit the wavelength-dependent
time delays of AGNs with a disc reprocessing models, what allows to measure
the distances to the AGNs. However this method needs to be improved in order
to determine more accurate estimation of cosmological quantities such as the
Hubble constant. After that, it could be conveniently applied to six-color AGN
lightcuves from LSST.

Primary author

Ms Aleksandra Olejak (CFT PAN)

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