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Post Info TOPIC: BAL QSOs
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RE: BAL QSOs
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Title: BAL QSOs and Extreme UFOs: the Eddington connection
Authors: Kastytis Zubovas, Andrew R. King

We suggest a common physical origin connecting the fast, highly ionised winds (UFOs) seen in nearby AGN, and the slower and less ionised winds of BAL QSOs. The primary difference is the mass loss rate in the wind, which is ultimately determined by the rate at which mass is fed towards the central supermassive black hole (SMBH) on large scales. This is below the Eddington accretion rate in most UFOs, and slightly super-Eddington in extreme UFOs such as PG1211+143, but ranges up to ~ 10-50 times this in BAL QSOs. For UFOs this implies black hole accretion rates and wind mass loss rates which are at most comparable to Eddington, giving fast, highly-ionised winds. In contrast BAL QSO black holes have mildly super-Eddington accretion rates, and drive winds whose mass loss rates are significantly super-Eddington, and so are slower and less ionised. This picture correctly predicts the velocities and ionisation states of the observed winds, including the recently-discovered one in SDSS J1106+1939. We suggest that luminous AGN may evolve through a sequence from BAL QSO through LoBAL to UFO-producing Seyfert or quasar as their Eddington factors drop during the decay of a bright accretion event. LoBALs correspond to a short-lived stage in which the AGN radiation pressure largely evacuates the ionisation cone, but before the large-scale accretion rate has dropped to the Eddington value. We show that sub-Eddington wind rates would produce an M - \sigma relation lying above that observed. We conclude that significant SMBH mass growth must occur in super-Eddington phases, either as BAL QSOs, extreme UFOs, or obscured from direct observation.

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Blobrana


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Posts: 131433
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Title: Deep GEMINI GMOS-IFU spectroscopy of BAL QSOs: I. Decoupling the BAL, QSO, starburst, NLR, and supergiant bubbles in Mrk 231
Authors: S. Lipari, S.F. Sanchez, M. Bergmann, R. Terlevich, B. Garcia-Lorenzo, B. Punsly, E. Mediavilla, Y. Taniguchi, M. Ajiki, W. Zheng, J. Acosta, K. Jahnke

In this work researchers present the first results of a study of BAL QSOs (at low and high redshift), based on very deep Gemini GMOS integral field spectroscopy. In particular, the results obtained for the nearest BAL IR QSO Mrk 231 are presented. Very deep three-dimensional spectra and maps clearly show that the BAL systems I and II are extended (reaching 1.4-1.6" = 1.2-1.3 kpc, from the nucleus) and clearly elongated at the position angle close to the radio jet PA. Which suggest that the BAL systems I and II are both associated with the radio jet, and supporting the bipolar jet-wind model for some BALs. For the nuclear region of Mrk 231, the QSO and host-galaxy components were modelled, using a new technique of decoupling 3D spectra.
From this study, the following main results were found:
(i) in the pure host galaxy spectrum an extreme nuclear starburst component was clearly observed, mainly as a very strong increase in the flux, at the blue wavelengths;
(ii) the BAL system I is observed in the spectrum of the host galaxy;
(iii) in the clean/pure QSO emission spectrum, only broad lines were detected. 3D GMOS individual spectra (specially in the IR Ca II triplet) and maps confirm the presence of an extreme and young nuclear starburst (8 < age < 15 Myr), which was detected mainly in a ring or toroid with a radius r = 0.3" = 200 pc, around the very nucleus. The physical properties of the four expanding nuclear bubbles were analysed, using the GMOS 3D spectra and maps. These results suggest that an important part of the nuclear NLR is generated by the OF process and the associated low velocity ionising shocks.

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