南方基地知识库

The changes of broad emission lines should be a crucial issue in understanding the physical properties of changinglook active galactic nuclei (CL-AGNs). Here we present the results of an intensive and homogeneous 6 month long reverberation mapping (RM) monitoring campaign during a low-activity state of the CL-AGN Seyfert galaxy NGC 3516. Photometric and spectroscopic monitoring was carried out during 2018-2019 with the Lijiang 2.4 m telescope. The sampling is 2 days in most nights, and the average sampling is similar to 3 days. The rest-frame time lags of Ha and H beta are H-T alpha = 7.56(+4242)(2.10) and H-T beta = 7.50(+2.05)(0.77) days, respectively. From an rms H beta line dispersion of sigma(line) = 1713.3 +/- 46.7 km s(-1) and a virial factor of f(sigma) = 5.5, the central black hole mass of NGC 3516 is estimated to be M-BH 2.4(+0.7)(-0.3) x 10(7)M circle dot, BH 0.30.7 7., which is in agreement with previous estimates. The velocity-resolved delays show that the time lags increase toward negative velocity for both Ha and H beta. The velocity-resolved RM of Ha is done for the first time. These RM results are consistent with other observations before the spectral-type change, indicating a basically constant broad-line region structure during the CL process. The CL model of changes of accretion rate seems to be favored by long-term H beta variability and RM observations of NGC 3516.