Here we report an identification of B3 0749+460 A as a new double-peaked local "changing-look" active galactic nucleus(CL-AGN) in terms of our multi-epoch spectroscopic analysis. By comparing our new spectra...Here we report an identification of B3 0749+460 A as a new double-peaked local "changing-look" active galactic nucleus(CL-AGN) in terms of our multi-epoch spectroscopic analysis. By comparing our new spectra taken in 2021 with the ones taken by the Sloan Digital Sky Survey in 2004, BOSS in 2013 and Ma NGA in 2016, we reveal type transitions of Seyfert(Sy) 1.9 → Sy1.8 → Sy1.9. In the transitions, the classical broad Hα emission fades away after 2013 and disappears in our 2021 spectrum, although the absence of broad Hβ can be traced back to at least 2016. A follow-up observation in X-rays by the Swift/XRT reveals that(1) the X-ray emission level gradually decreased since 2005;and(2)the X-ray spectrum is soft in the optical "turn-off" state and hard in the "turn-on" state. We argue that the disappearance of the classical broad Hα emission can be likely explained by the disk-wind broad-line-region model, in which the CL phenomenon is sensitive to luminosity in individual AGNs.展开更多
基金support from the National Key Research and Development Project of China (grant 2020YFE0202100)supported by the National Natural Science Foundation of China (Grants No.11773036 and 12173009)+6 种基金Strategic Pioneer Program on Space ScienceChinese Academy of Sciences,grants XDA15052600 and XDA15016500supported by the Natural Science Foundation of Guangxi(2020GXNSFDA238018)the Bagui Young Scholars Programsupported by the Open Project Program of the Key Laboratory of Optical Astronomy,NAOC,CASsupported by the Christopher R.Redlich Fund and the Miller Institute for Basic Research in Science (in which A.V.F.is a Senior Miller Fellow) funded by the National Aeronautics and Space Administration (NASA)partially supported by a generous gift from Google。
文摘Here we report an identification of B3 0749+460 A as a new double-peaked local "changing-look" active galactic nucleus(CL-AGN) in terms of our multi-epoch spectroscopic analysis. By comparing our new spectra taken in 2021 with the ones taken by the Sloan Digital Sky Survey in 2004, BOSS in 2013 and Ma NGA in 2016, we reveal type transitions of Seyfert(Sy) 1.9 → Sy1.8 → Sy1.9. In the transitions, the classical broad Hα emission fades away after 2013 and disappears in our 2021 spectrum, although the absence of broad Hβ can be traced back to at least 2016. A follow-up observation in X-rays by the Swift/XRT reveals that(1) the X-ray emission level gradually decreased since 2005;and(2)the X-ray spectrum is soft in the optical "turn-off" state and hard in the "turn-on" state. We argue that the disappearance of the classical broad Hα emission can be likely explained by the disk-wind broad-line-region model, in which the CL phenomenon is sensitive to luminosity in individual AGNs.
