The Seoul National University AGN Monitoring Project. III. Hβ Lag Measurements of 32 Luminous Active Galactic Nuclei and the High-luminosity End of the Size–Luminosity Relation

February 2024 • 2024ApJ...962...67W

Authors • Woo, Jong-Hak • Wang, Shu • Rakshit, Suvendu • Cho, Hojin • Son, Donghoon • Bennert, Vardha N. • Gallo, Elena • Hodges-Kluck, Edmund • Treu, Tommaso • Barth, Aaron J. • Cho, Wanjin • Foord, Adi • Geum, Jaehyuk • Guo, Hengxiao • Jadhav, Yashashree • Jeon, Yiseul • Kabasares, Kyle M. • Kang, Won-Suk • Kim, Changseok • Kim, Minjin • Kim, Tae-Woo • Le, Huynh Anh N. • Malkan, Matthew A. • Mandal, Amit Kumar • Park, Daeseong • Spencer, Chance • Shin, Jaejin • Sung, Hyun-il • U, Vivian • Williams, Peter R. • Yee, Nick

Abstract • We present the main results from a long-term reverberation mapping campaign carried out for the Seoul National University AGN Monitoring Project (SAMP). High-quality data were obtained during 2015–2021 for 32 luminous active galactic nuclei (AGNs; i.e., continuum luminosity in the range of 10^44–46 erg s^‑1) at a regular cadence, of 20–30 days for spectroscopy and 3–5 days for photometry. We obtain time lag measurements between the variability in the Hβ emission and the continuum for 32 AGNs; 25 of those have the best lag measurements based on our quality assessment, examining correlation strength and the posterior lag distribution. Our study significantly increases the current sample of reverberation-mapped AGNs, particularly at the moderate-to-high-luminosity end. Combining our results with literature measurements, we derive an Hβ broadline region size–luminosity relation with a shallower slope than reported in the literature. For a given luminosity, most of our measured lags are shorter than the expectations, implying that single-epoch black hole mass estimators based on previous calibrations could suffer large systematic uncertainties.

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Vivian U

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