000004756 001__ 4756
000004756 005__ 20200203154919.0
000004756 0247_ $$2DOI$$a10.3847/2041-8213/ab3d41
000004756 037__ $$aSCART-2020-0056
000004756 100__ $$aDehghanian, M.
000004756 245__ $$aA Wind-based Unification Model for NGC 5548: Spectral Holidays, Nondisk Emission, and Implications for Changing-look Quasars
000004756 260__ $$c2019
000004756 520__ $$aThe 180 day Space Telescope and Optical Reverberation Mapping campaign on NGC 5548 discovered an anomalous period, the broad-line region (BLR) holiday, in which the emission lines decorrelated from the continuum variations. This is important since the correlation between the continuum-flux variations and the emission-line response is the basic assumption for black hole (BH) mass determinations through reverberation mapping. During the BLR holiday the high-ionization intrinsic absorption lines also decorrelated from the continuum as a result of the variable covering factor of the line-of-sight (LOS) obscurer. The emission lines are not confined to the LOS, so this does not explain the BLR holiday. If the LOS obscurer is a disk wind, its streamlines must extend down to the plane of the disk and the base of the wind would lie between the BH and the BLR, forming an equatorial obscurer. This obscurer can be transparent to ionizing radiation, or can be translucent, blocking only parts of the spectral energy distribution, depending on its density. An emission-line holiday is produced if the wind density increases only slightly above its transparent state. Both obscurers are parts of the same wind, so they can have associated behavior in a way that explains both holidays. A very dense wind would block nearly all ionizing radiation, producing a Seyfert 2 and possibly providing a contributor to the changing-look active galactic nucleus phenomenon. Disk winds are very common and we propose that the equatorial obscurers are too, but mostly in a transparent state.
000004756 594__ $$aNO
000004756 6531_ $$agalaxies: active
000004756 6531_ $$agalaxies: individual: NGC 5548
000004756 6531_ $$agalaxies: nuclei
000004756 6531_ $$agalaxies: Seyfert
000004756 6531_ $$aline: formation
000004756 6531_ $$aAstrophysics - Astrophysics of Galaxies
000004756 700__ $$aFerland, G. J.
000004756 700__ $$aPeterson, B. M.
000004756 700__ $$aKriss, G. A.
000004756 700__ $$aKorista, K. T.
000004756 700__ $$aChatzikos, M.
000004756 700__ $$aGuzmán, F.
000004756 700__ $$aArav, N.
000004756 700__ $$aDe Rosa, G.
000004756 700__ $$aGoad, M. R.
000004756 700__ $$aMehdipour, M.
000004756 700__ $$avan Hoof, P. A. M.
000004756 773__ $$cL30 (6 pages)$$n2$$pThe Astrophysical Journal$$v882$$y2019
000004756 8560_ $$fpeter.vanhoof@observatoire.be
000004756 85642 $$ahttps://arxiv.org/abs/1908.07686
000004756 905__ $$apublished in
000004756 980__ $$aREFERD