1. The Seoul National University AGN Monitoring Project IV: H$\alpha$ reverberation mapping of 6 AGNs and the H$\alpha$ Size-Luminosity Relation
- Author
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Cho, Hojin, Woo, Jong-Hak, Wang, Shu, Son, Donghoon, Shin, Jaejin, Rakshit, Suvendu, Barth, Aaron J., Bennert, Vardha N., Gallo, Elena, Hodges-Kluck, Edmund, Treu, Tommaso, Bae, Hyun-Jin, Cho, Wanjin, Foord, Adi, Geum, Jaehyuk, Jadhav, Yashashree, Jeon, Yiseul, Kabasares, Kyle M., Kang, Daeun, Kang, Wonseok, Kim, Changseok, Kim, Donghwa, Kim, Minjin, Kim, Taewoo, Le, Huynh Anh N., Malkan, Matthew A., Mandal, Amit Kumar, Park, Daeseong, Park, Songyoun, Sung, Hyun-il, U, Vivian, and Williams, Peter R.
- Subjects
Astrophysics - Astrophysics of Galaxies - Abstract
The broad line region (BLR) size-luminosity relation has paramount importance for estimating the mass of black holes in active galactic nuclei (AGNs). Traditionally, the size of the H$\beta$ BLR is often estimated from the optical continuum luminosity at 5100\angstrom{} , while the size of the H$\alpha$ BLR and its correlation with the luminosity is much less constrained. As a part of the Seoul National University AGN Monitoring Project (SAMP) which provides six-year photometric and spectroscopic monitoring data, we present our measurements of the H$\alpha$ lags of 6 high-luminosity AGNs. Combined with the measurements for 42 AGNs from the literature, we derive the size-luminosity relations of H$\alpha$ BLR against broad H$\alpha$ and 5100\angstrom{} continuum luminosities. We find the slope of the relations to be $0.61\pm0.04$ and $0.59\pm0.04$, respectively, which are consistent with the \hb{} size-luminosity relation. Moreover, we find a linear relation between the 5100\angstrom{} continuum luminosity and the broad H$\alpha$ luminosity across 7 orders of magnitude. Using these results, we propose a new virial mass estimator based on the H$\alpha$ broad emission line, finding that the previous mass estimates based on the scaling relations in the literature are overestimated by up to 0.7 dex at masses lower than $10^7$~M$_{\odot}$., Comment: Accepted for publication in ApJ (Jun. 25th, 2023). 21 pages, 12 figures
- Published
- 2023