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Quasar accretion disk sizes from continuum reverberation mapping from the Dark Energy Survey
journal contribution
posted on 2023-06-09, 15:10 authored by D Mudd, P Martini, Y Zu, C Kochanek, B M Peterson, R Kessler, T M Davis, J K Hoormann, A King, C Lidman, Kathy RomerKathy Romer, DES CollaborationWe present accretion disk size measurements for 15 luminous quasars at 0.7???z???1.9 derived from griz light curves from the Dark Energy Survey. We measure the disk sizes with continuum reverberation mapping using two methods, both of which are derived from the expectation that accretion disks have a radial temperature gradient and the continuum emission at a given radius is well described by a single blackbody. In the first method we measure the relative lags between the multiband light curves, which provides the relative time lag between shorter and longer wavelength variations. From this, we are only able to constrain upper limits on disk sizes, as many are consistent with no lag the 2s level. The second method fits the model parameters for the canonical thin disk directly rather than solving for the individual time lags between the light curves. Our measurements demonstrate good agreement with the sizes predicted by this model for accretion rates between 0.3 and 1 times the Eddington rate. Given our large uncertainties, our measurements are also consistent with disk size measurements from gravitational microlensing studies of strongly lensed quasars, as well as other photometric reverberation mapping results, that find disk sizes that are a factor of a few (~3) larger than predictions.
History
Publication status
- Published
File Version
- Published version
Journal
Astrophysical JournalISSN
0004-637XPublisher
American Astronomical SocietyExternal DOI
Issue
123Volume
862Page range
1-13Department affiliated with
- Physics and Astronomy Publications
Research groups affiliated with
- Astronomy Centre Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2018-09-24First Open Access (FOA) Date
2018-09-24First Compliant Deposit (FCD) Date
2018-09-21Usage metrics
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