Results 81 to 90 of about 365 (183)

BALNet: Deep-learning-based Detection and Measurement of Broad Absorption Lines in Quasar Spectra

The Astrophysical Journal Supplement Series
Broad absorption line (BAL) quasars serve as critical probes for understanding outflows from active galactic nuclei, black hole accretion, and cosmic evolution.
Yangyang Li, Zhijian Luo, Shaohua Zhang, Du Wang, Jianzhen Chen, Zhu Chen, Hubing Xiao, Chenggang Shu   +7 more
doaj   +1 more source

Deep-Learning-Based Identification of Broad-Absorption Line Quasars

Applied Sciences
The accurate classification of broad-absorption line (BAL) quasars and non-broad-absorption line (non-BAL) quasars is key in understanding active galactic nuclei (AGN) and the evolution of the universe.
Sen Pang, Hoiio Kong, Zijun Li, Weibo Kao, Yanxia Zhang   +4 more
doaj   +1 more source

A Potential Link between Nuclear Winds and Cold Gas Outflows on Kiloparsec Scales in Reionization-era Quasars

The Astrophysical Journal
Feedback from accreting supermassive black holes may regulate galaxy evolution, but statistical evidence linking nuclear winds to kiloparsec-scale cold gas outflows remains limited in the early Universe.
Yongda Zhu, Marcia J. Rieke, Luis C. Ho, Yang Sun, George H. Rieke, Feng Yuan, Tom J. L. C. Bakx, George D. Becker, Jinyi Yang, Eduardo Bañados, Manuela Bischetti, Christopher Cain, Xiaohui Fan, Yoshinobu Fudamoto, Seyedazim Hashemi, Ryota Ikeda, Zhiyuan Ji, Xiangyu Jin, Weizhe Liu, Yichen Liu, Jianwei Lyu, Hai-Xia Ma, Tsutomu T. Takeuchi, Hideki Umehata, Feige Wang, Wei Leong Tee   +25 more
doaj   +1 more source

AGN with extreme X-ray amplitude variations

EPJ Web of Conferences, 2012
We present active galactic nuclei (AGNs) that have shown extreme amplitude variability in X-rays. These AGN appear as bright for long periods, but then suddenly become extremely X-ray weak sources.
Gallo L.C., Leighly K.M., Komossa S., Grupe D.   +3 more
doaj   +1 more source

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Quasar Survey: Quasar Properties from Data Releases 10 to 12

The Astrophysical Journal Supplement Series
We present the quasar catalog from Data Releases 10 to 12 of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) Quasar Survey, comprising quasars observed between 2021 September and 2024 June. We robustly identified 11,346 quasars, of
Bing Lyu, Xue-Bing Wu, Jun-Jie Jin, Yuming Fu, Yuxuan Pang, Huimei Wang, Rui Zhu, Su Yao, Yan-Li Ai, Yan-xia Zhang, Hai-long Yuan, Zhi-ying Huo   +11 more
doaj   +1 more source

Tracing the massive inflows feeding super-massive black holes in quasars. [PDF]

Innovation (Camb), 2023
Jiang P, Shi X, Zhou H.
europepmc   +1 more source

The Quasar-associated 2175 Å Dust Absorbers in the SDSS DR16 Quasar Catalog

The Astrophysical Journal Supplement Series
We present, for the first time, a systematic study of quasar-associated 2175 Å dust absorbers using spectroscopic data from the Sloan Digital Sky Survey Data Release 16 (DR16).
Shaohua Zhang, Yuchong Luo, Shangchun Xie, Chao Gao, Zhijian Luo, Chenggang Shu, Hubing Xiao   +6 more
doaj   +1 more source

Transient LoBALs at High Velocities: A Case of Extreme Broad Absorption Line Variability in J115636.82+085628.9

The Astrophysical Journal
We present a multiepoch spectroscopic study of the broad absorption line (BAL) quasar J115636.82+085628.9 ( z _em  = 2.1077), based on five spectra spanning nearly two decades in the observer’s frame.
P. Aromal, R. Srianand, S. C. Gallagher, M. Vivek, P. Petitjean   +4 more
doaj   +1 more source

QUEST: Quasar unsupervised encoder and synthesis tool

Astronomy & Astrophysics
Context. Quasars at the redshift frontier (z > 7.0) are fundamental probes of black hole growth and evolution, but are notoriously difficult to identify.
Guarneri F., Schindler J. T., Meyer R. A., Yang D., Hennawi J. F., Lucie-Smith L., Bosman S. E. I., Davies F. B.   +7 more
doaj   +1 more source

Circumnuclear Gas of a Quasar in Absorption and Emission Lines

The Astrophysical Journal
We present a detailed analysis of the unusual absorption- and emission-line spectrum of the quasar SDSS J074850.39+442439.0 (hereafter J0748+4424) at a redshift of z = 2.18. The archival SDSS optical spectrum is abundant in narrow absorption lines (NALs)
Xuejie Dai, Lei Hao, Peng Jiang, Zhenzhen Li, Xiheng Shi, Shengmiao Wu, Yanfei Zou, Yipeng Zhou, Tuo Ji, Qiguo Tian, Bo Liu, Lin Lin, Hongyan Zhou   +12 more
doaj   +1 more source