@article{658359f3d5b2456bb1117cc60e7d183a,
title = "The SDSS-V Black Hole Mapper Reverberation Mapping Project: C iv Broad Absorption Line Acceleration in the Quasar SBS 1408+544",
abstract = "We present the results of an investigation of a highly variable C iv broad absorption line (BAL) feature in spectra of the quasar SBS 1408+544 (z = 2.337) that shows a significant shift in velocity over time. This source was observed as a part of the Sloan Digital Sky Survey (SDSS) Reverberation Mapping project and the SDSS-V Black Hole Mapper Reverberation Mapping project, and has been included in two previous studies, both of which identified significant variability in a high-velocity C iv BAL on timescales of just a few days in the quasar rest frame. Using ∼130 spectra acquired over 8 yr of spectroscopic monitoring with SDSS, we have determined that this BAL is not only varying in strength, but is also systematically shifting to higher velocities. Using cross-correlation methods, we measure the velocity shifts (and corresponding acceleration) of the BAL over a wide range of timescales, measuring an overall velocity shift of Δ v = − 683 − 84 + 89 km s−1 over the 8 yr monitoring period. This corresponds to an average rest-frame acceleration of a = 1.04 − 0.13 + 0.14 cm s−2, though the magnitude of the acceleration on shorter timescales is not constant throughout. We place our measurements in the context of BAL-acceleration models and examine various possible causes of the observed velocity shift.",
author = "Robert Wheatley and Grier, \{Catherine J.\} and Hall, \{Patrick B.\} and Brandt, \{W. N.\} and Jonah Lotz and Schneider, \{D. P.\} and Trump, \{Jonathan R.\} and Yue Shen and Seaton, \{Lucas M.\} and Anderson, \{Scott F.\} and Temple, \{Matthew J.\} and Roberto Assef and Fries, \{Logan B.\} and Y. Homayouni and Darshan Kakkad and Koekemoer, \{Anton M.\} and Mart{\'i}nez-Aldama, \{Mary Loli\} and Negrete, \{C. Alenka\} and Claudio Ricci and Dmitry Bizyaev and Brownstein, \{Joel R.\} and Sean Morrison and Kaike Pan",
note = "This work includes observations obtained with the Hobby\textbackslash{}u2013Eberly Telescope (HET), which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Ludwig-Maximillians-Universitaet Muenchen, and Georg-August Universitaet Goettingen. The HET is named in honor of its principal benefactors, William P. Hobby and Robert E. Eberly. The Low Resolution Spectrograph 2 (LRS2) was developed and funded by the University of Texas at Austin McDonald Observatory and Department of Astronomy, and by Pennsylvania State University. We thank the Leibniz-Institut fur Astrophysik Potsdam (AIP) and the Institut fur Astrophysik Goettingen (IAG) for their contributions to the construction of the integral field units. We acknowledge the Texas Advanced Computing Center (TACC) at The University of Texas at Austin for providing high-performance computing, visualization, and storage resources that have contributed to the results reported within this paper. R.W. and C.J.G. acknowledge support from NSF grants AST-2310211 and AST-2309930. Support for this research was provided by the Office of the Vice Chancellor for Research and Graduate Education at the University of Wisconsin Madison with funding from the Wisconsin Alumni Research Foundation. P.B.H. acknowledges support from NSERC grant 2023-05068. W.N.B. acknowledges support from NSF grant AST-2106990. Y.S. acknowledges partial support from NSF grants AST-2009947 and AST-2108162. Y.H. was supported as an Eberly Research Fellow by the Eberly College of Science at the Pennsylvania State University. C.R. acknowledges support from the Fondecyt Iniciacion grant 11190831 and ANID BASAL project FB210003. R.J.A. was supported by FONDECYT grant No. 123171 and by the ANID BASAL project FB210003. M.L.M.-A. acknowledges financial support from Millennium Nucleus NCN19-058 and NCN2023\_002 (TITANs). C.A.N. thanks support from CONAHCyT project Paradigmas y Controversias de la Ciencia 2022-320020 and DGAPA-UNAM grant IN111422. Funding for the Sloan Digital Sky Survey V has been provided by the Alfred P. Sloan Foundation, the Heising-Simons Foundation, the National Science Foundation, and the Participating Institutions. SDSS acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS website is www.sdss.org .",
year = "2024",
month = jun,
day = "1",
doi = "10.3847/1538-4357/ad429e",
language = "English (US)",
volume = "968",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "American Astronomical Society",
number = "2",
}