X-ray selected broad absorption line quasars in SDSS-V: BALs and non-BALs span the same range of X-ray properties

作者：Pranavi Hiremath, Amy L. Rankine, James Aird, W. N. Brandt, Paola Rodríguez Hidalgo, Scott F. Anderson, Catarina Aydar, Cláudio Ricci, Donald P. Schneider, M. Vivek, Z. Igo, Sean Morrison, M. Salvato · 发表于：Monthly Notices of the Royal Astronomical Society · 年份：2025 · DOI：10.1093/mnras/staf1352 · 被引用次数：5 · 研究领域：Astrophysical Phenomena and Observations、Galaxies: Formation, Evolution, Phenomena、Gamma-ray bursts and supernovae

ABSTRACT Broad absorption line (BAL) quasars are often considered X-ray weak relative to their optical/UV luminosity, whether intrinsically (i.e. the coronal emission is fainter) or due to large column densities of absorbing material. The SDSS-V is providing optical spectroscopy for samples of quasar candidates identified by eROSITA as well as Chandra, XMM, or Swift, making the resulting data sets ideal for characterizing the BAL quasar population within an X-ray selected sample. We use the Balnicity Index (BI) to identify the BAL quasars based on absorption of the C iv$\lambda \, 1549$ emission line in the optical spectra, finding 143 BAL quasars in our sample of 2317 X-ray selected quasars within $1.5\le z \le 3.5$. This observed BAL fraction of $\approx$ 6 per cent is comparable to that found in optically selected samples. We also identify absorption systems via the Absorption Index (AI) which includes mini-BALs and NALs, finding 954 quasars with AI $>0$. We consider the C iv emission space (equivalent width versus blueshift) to study the BAL outflows within the context of the radiatively driven accretion disc–wind model. X-ray selection excludes the highest outflow velocities in emission but includes the full range of absorption velocities which we suggest is consistent with the BAL gas being located further from the X-ray corona than the emitting gas. We observe both X-ray weak and X-ray strong BALs (via the optical-to-X-ray spectral slope, $\alpha _\text{ox}$) an...