A Quasar Shedding Its Dust Cocoon at Redshift 2

• Published in: The Astrophysical journal 2022-05, Vol.930 (1), p.5
• Main Authors: Yi, Weimin, Brandt, W. N., Ni, Q., Ho, Luis C., Luo, Bin, Yan, Wei, Schneider, D. P., Paul, Jeremiah D., Plotkin, Richard M., Yang, Jinyi, Wang, Feige, He, Zhicheng, Chen, Chen, Wu, Xue-Bing, Bai, Jin-Ming
• Format: Article
• Language: English
• Subjects: Astronomy & Astrophysics; ASTRONOMY AND ASTROPHYSICS; Astrophysics; Black holes; Blue shift; Broad-absorption line quasar; Deposition; Dust; Emissions; Galaxies; Infrared spectroscopy; Luminosity; Near infrared radiation; Quasars; Red shift; Spectroscopy; Supermassive black holes; Uncertainty
• ISSN: 0004-637X; 1538-4357
• DOI: 10.3847/1538-4357/ac6109

We present the first near-IR spectroscopy and joint analyses of multiwavelength observations for SDSS J082747.14+425241.1, a dust-reddened, weak broad emission-line quasar (WLQ) undergoing a remarkable broad-absorption line (BAL) transformation. The systemic redshift is more precisely measured to be z = 2.070 ± 0.001 using H β compared to z = 2.040 ± 0.003 using Mg ii from the literature, signifying an extreme Mg ii blueshift of 2140 ± 530 km s −1 relative to H β . Using the H β -based single-epoch scaling relation with a systematic uncertainty of 0.3 dex, its black hole (BH) mass and Eddington ratio are estimated to be M BH ∼ 6.1 × 10 8 M ⊙ and λ Edd ∼ 0.71, indicative of being in a rapidly accreting phase. Our investigations confirm the WLQ nature and the LoBAL → HiBAL transformation, along with a factor of 2 increase in the Mg ii +Fe ii emission strength and a decrease of 0.1 in E ( B − V ) over two decades. The kinetic power of this LoBAL wind at R ∼ 15 pc from its BH is estimated to be ∼43% of the Eddington luminosity, sufficient for quasar feedback upon its host galaxy albeit with an order-of-magnitude uncertainty. This quasar provides a clear example of the long-sought scenario where LoBAL quasars are surrounded by dust cocoons, and wide-angle nuclear winds play a key role in the transition of red quasars evolving into the commonly seen blue quasars.