@article{23e8cbf206774430a406c3f99a0ce204,
title = "Broad absorption line disappearance and emergence using multiple-epoch spectroscopy from the Sloan Digital Sky Survey",
abstract = "We investigate broad absorption line (BAL) disappearance and emergence using a 470 BALquasar sample over ≤0.10-5.25 rest-frame years with at least three spectroscopic epochs for each quasar from the Sloan Digital Sky Survey. We identify 14 disappearing BALs over≤1.73-4.62 rest-frame years and 18 emerging BALs over ≤1.46-3.66 rest-frame years associated with the C IV λλ1548,1550 and/or Si IV λλ1393,1402 doublets, and report on their variability behaviour. BAL quasars in our data set exhibit disappearing/emerging C IV BALs at a rate of 2.3-0.7+0.9 and 3.0-0.8+1.0 per cent, respectively, and the frequency for BAL to non-BAL quasar transitions is 1.7-0.6+0.8 per cent. We detect four re-emerging BALs over ≤3.88 rest-frame years on average and three re-disappearing BALs over ≤4.15 rest-frame years on average, the first reported cases of these types. We infer BAL lifetimes along the line of sight to be nominally ≲100-1000 yr using disappearing C IV BALs in our sample. Interpretations of (re-)emerging and (re-)disappearing BALs reveal evidence that collectively supports both transverse-motion and ionization-change scenarios to explain BAL variations. We constrain a nominal C IV/Si IV BAL-outflow location of ≲100 pc from the central source and a radial size of ≳1× 10-7 pc (0.02 au) using the ionization-change scenario, and constrain a nominal outflow location of ≲0.5 pc and a transverse size of ~0.01 pc using the transverse-motion scenario. Our findings are consistent with previous work, and provide evidence in support of BALs tracing compact flow geometries with small filling factors.",
author = "McGraw, {S. M.} and Brandt, {W. N.} and Grier, {C. J.} and Ak, {N. Filiz} and Hall, {P. B.} and Schneider, {D. P.} and Anderson, {S. F.} and Green, {P. J.} and Hutchinson, {T. A.} and Macleod, {C. L.} and M. Vivek",
note = "Funding Information: We thank the referee for a constructive report. We acknowledge support from NSF grant AST-1516784 (SMM, WNB), NSF grant AST-1517113 (WNB, CJG, DPS), NSERC (PBH) and TUBITAK 115F037 (NFA). Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSSIV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrof{\'i}sica de Canarias, the Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut f{\"u}r Astrophysik Potsdam (AIP), Max-Planck-Institut f{\"u}r Astronomie (MPIA Heidelberg), Max-Planck-Institut f{\"u}r Astrophysik (MPA Garching), Max-Planck-Institut f{\"u}r Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observat{\'a}rio Nacional/MCTI, the Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Aut{\'o}noma deM{\'e}xico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University. The CSS survey is funded by the National Aeronautics and Space Administration under Grant No. NNG05GF22G issued through the Science Mission Directorate Near-Earth Objects Observations Program. The CRTS survey is supported by the US National Science Foundation under grants AST-0909182 and AST-1313422. Funding Information: We thank the referee for a constructive report. We acknowledge support from NSF grant AST-1516784 (SMM, WNB), NSF grant AST-1517113 (WNB, CJG, DPS), NSERC (PBH) and TUBITAK 115F037 (NFA). Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSSIV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrof?sica de Canarias, the Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut f?r Astrophysik Potsdam (AIP), Max-Planck-Institut f?r Astronomie (MPIA Heidelberg), Max-Planck-Institut f?r Astrophysik (MPA Garching), Max-Planck-Institut f?r Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observat?rio Nacional/MCTI, the Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Aut?noma deM?xico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University. The CSS survey is funded by the National Aeronautics and Space Administration under Grant No. NNG05GF22G issued through the Science Mission Directorate Near-Earth Objects Observations Program. The CRTS survey is supported by the US National Science Foundation under grants AST-0909182 and AST-1313422. Funding Information: We thank the referee for a constructive report. We acknowledge support from NSF grant AST–1516784 (SMM, WNB), NSF grant AST–1517113 (WNB, CJG, DPS), NSERC (PBH) and TUBITAK 115F037 (NFA). Funding Information: The CSS survey is funded by the National Aeronautics and Space Administration under Grant No. NNG05GF22G issued through the Science Mission Directorate Near-Earth Objects Observations Program. The CRTS survey is supported by the US National Science Foundation under grants AST-0909182 and AST-1313422. Funding Information: Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org. Publisher Copyright: {\textcopyright} 2017 The Authors.",
year = "2017",
month = aug,
day = "11",
doi = "10.1093/mnras/stx1063",
language = "English (US)",
volume = "469",
pages = "3163--3184",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "3",
}