The Lick AGN Monitoring Project: Reverberation Mapping of Optical Hydrogen and Helium Recombination Lines - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We have recently completed a 64-night spectroscopic monitoring campaign atthe Lick Observatory 3-m Shane telescope with the aim of measuring the massesof the black holes in 12 nearby z < 0.05 Seyfert 1 galaxies with expectedmasses in the range ~10^6-10^7M sun and also the well-studied nearby activegalactic nucleus AGN NGC 5548. Nine of the objects in the sample includingNGC 5548 showed optical variability of sufficient strength during themonitoring campaign to allow for a time lag to be measured between thecontinuum fluctuations and the response to these fluctuations in the broadHbeta emission, which we have previously reported. We present here the lightcurves for the Halpha, Hgamma, HeII 4686, and HeI 5876 emission lines and thetime lags for the emission-line responses relative to changes in the continuumflux. Combining each emission-line time lag with the measured width of the linein the variable part of the spectrum, we determine a virial mass of the centralsupermassive black hole from several independent emission lines. We find thatthe masses are generally consistent within the uncertainties. The time-lagresponse as a function of velocity across the Balmer line profiles is examinedfor six of the AGNs. Finally we compare several trends seen in the datasetagainst the predictions from photoionization calculations as presented byKorista and Goad. We confirm several of their predictions, including an increasein responsivity and a decrease in the mean time lag as the excitation andionization level for the species increases. Further confirmation ofphotoionization predictions for broad-line gas behavior will require additionalmonitoring programs for these AGNs while they are in different luminositystates. abridged



Autor: Misty C. Bentz 1,2, Jonelle L. Walsh 1, Aaron J. Barth 1, Yuzuru Yoshii 3, Jong-Hak Woo 4,5, Xiaofeng Wang 6,7,8, Tommaso Treu 9,

Fuente: https://arxiv.org/







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