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Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories
- Source :
- The Astrophysical Journal, Vol 953, Iss 2, p 137 (2023)
- Publication Year :
- 2023
- Publisher :
- IOP Publishing, 2023.
-
Abstract
- Continuum reverberation mapping probes the size scale of the optical continuum-emitting region in active galactic nuclei (AGN). Through 3 yr of multiwavelength photometric monitoring in the optical with robotic observatories, we perform continuum reverberation mapping on Mrk 876. All wave bands show large-amplitude variability and are well correlated. Slow variations in the light curves broaden the cross-correlation function (CCF) significantly, requiring detrending in order to robustly recover interband lags. We measure consistent interband lags using three techniques (CCF, JAVELIN, and PyROA), with a lag of around 13 days from u to z . These lags are longer than the expected radius of 12 days for the self-gravitating radius of the disk. The lags increase with wavelength roughly following λ ^4/3 , as would be expected from thin disk theory, but the lag normalization is approximately a factor of 3 longer than expected, as has also been observed in other AGN. The lag in the i band shows an excess that we attribute to variable H α broad-line emission. A flux–flux analysis shows a variable spectrum that follows f _ν ∝ λ ^−1/3 , as expected for a disk, and an excess in the i band that also points to strong variable H α emission in that band.
Details
- Language :
- English
- ISSN :
- 15384357
- Volume :
- 953
- Issue :
- 2
- Database :
- Directory of Open Access Journals
- Journal :
- The Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.27f915f3f4047e1a003a3f7a82692a7
- Document Type :
- article
- Full Text :
- https://doi.org/10.3847/1538-4357/ace342