2017/09/30 by Andreas Schulze, Malte Schramm, Wenwen Zuo +9 · 28 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Astrophysics #Emission spectrum #Galaxies: Formation, Evolution, Phenomena #Galaxy #Luminosity #Physics #QSOS #Quasar #Redshift #Spectral line #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/aa8e4c
published in The Astrophysical Journal 848(2), 104 (IOP Publishing) · 13 pages, 12 figures, accepted for publication in ApJ
openalex created_date 2017/09/25 · openalex publication_date 2017/10/20 · arxiv created 2017/10/25 · arxiv updated 2017/11/01 · openalex updated_date 2026/08/05
Abstract We present near-IR spectroscopy of 22 luminous low-ionization broad absorption line quasars (LoBAL QSOs) at redshift , with 12 objects at z ∼ 1.5 and 10 at z ∼ 2.3. The spectra cover the rest-frame H α and H β line regions, allowing us to obtain robust black hole mass estimates based on the broad H α line. We use these data, augmented by a lower-redshift sample from the Sloan Digital Sky Survey, to test the proposed youth scenario for LoBALs, which suggests that LoBALs constitute an early short-lived evolutionary stage of quasar activity, by probing for any difference in their masses, Eddington ratios, or rest-frame optical spectroscopic properties compared to normal quasars. In addition, we construct the UV to mid-IR spectral energy distributions (SEDs) for the LoBAL sample and a matched non-BAL quasar sample. We do not find any statistically significant difference between LoBAL QSOs and non-BAL QSOs in their black hole mass or Eddington ratio distributions. The mean UV to mid-IR SED of the LoBAL QSOs is consistent with non-BAL QSOs, apart from their stronger reddening. At there is no clear difference in their optical emission line properties. We do not see particularly weak [O iii ] or strong Fe ii emission. The LoBAL QSOs do not show a stronger prevalence of ionized gas outflows as traced by the [O iii ] line, compared to normal QSOs of similar luminosity. We conclude that the optical–MIR properties of LoBAL QSOs are consistent with the general quasar population and do not support them to constitute a special phase of active galactic nucleus evolution.