Results 71 to 80 of about 1,686 (186)

ISO Observations of Quasars and Quasar Hosts [PDF]

, 1997
The Infrared Space Observatory (ISO), launched in November 1995, allows us to measure the far-infrared (far-IR) emission of quasars in greater detail and over a wider energy range than previously possible. In this paper, preliminary results in a study of the 5--200 $μm$ continuum of quasars and active galaxies are presented.
openaire   +2 more sources

Quest for a Coherent Definition of Weak-line Quasars and Its Physical Implications

The Astrophysical Journal
Weak-line quasars (WLQs) represent a subset of type 1 quasars distinguished by remarkably weak high-ionization broad emission lines, yet exhibiting normal optical/UV continua. This study establishes a physically motivated definition of WLQs using 371,091
Xiaoqiang Cheng, Jianfeng Wu, Qiaoya Wu
doaj   +1 more source

Extreme Variability Quasars in Their Various States. II. Spectral Variation Revealed with Multiepoch Spectra

The Astrophysical Journal
We previously built a sample of 14,012 extremely variable quasars (EVQs) based on Sloan Digital Sky Survey (SDSS) and Pan-STARRS1 photometric observations.
Wenke Ren, Junxian Wang, Zhenyi Cai, Xufan Hu   +3 more
doaj   +1 more source

Prospects for Observing High-redshift Radio-loud Quasars in the SKA Era: Paving the Way for 21 cm Forest Observations

The Astrophysical Journal
The 21 cm forest is a sensitive probe for the early heating process and small-scale structures during the epoch of reionization (EOR), to be realized with the upcoming Square Kilometre Array (SKA). Its detection relies on the availability of radio-bright
Qi Niu, Yichao Li, Yidong Xu, Hong Guo, Xin Zhang   +4 more
doaj   +1 more source

A Pilot Study for the CSST Slitless Spectroscopic Quasar Survey Based on Mock Data

The Astrophysical Journal
The wide survey of the Chinese Space Station Telescope (CSST) will observe a large field of 17,500 deg ^2 . The GU, GV, and GI grism observations of CSST will cover the wavelength range from 2550 to 10000 Å at a resolution of R  ∼ 200 and a depth of ...
Yuxuan Pang, Xue-Bing Wu, Yuming Fu, Rui Zhu, Bing Lyu, Huimei Wang, Xiaotong Feng   +6 more
doaj   +1 more source

Cosmic Himalayas: The Highest Quasar Density Peak Identified in a 10,000 deg2 Sky with Spatial Discrepancies between Galaxies, Quasars, and IGM H i

The Astrophysical Journal
We report the identification of a quasar overdensity in the BOSSJ0210 field, dubbed the Cosmic Himalayas, consisting of 11 quasars at z = 2.16−2.20, the densest overdensity of quasars (17 σ ) in the ∼10,000 deg ^2 of the Sloan Digital Sky Survey (SDSS ...
Yongming Liang, Masami Ouchi, Dongsheng Sun, Nobunari Kashikawa, Zheng Cai, Sebastiano Cantalupo, Kentaro Nagamine, Hidenobu Yajima, Takanobu Kirihara, Haibin Zhang, Mingyu Li, Rhythm Shimakawa, Xiaohui Fan, Kei Ito, Masayuki Tanaka, Yuichi Harikane, J. Xavier Prochaska, Andrea Travascio, Weichen Wang, Martin Elvis, Giuseppina Fabbiano, Junya Arita, Masafusa Onoue, John D. Silverman, Dong Dong Shi, Fangxia An, Takuma Izumi, Kazuhiro Shimasaku, Hisakazu Uchiyama, Chenghao Zhu   +29 more
doaj   +1 more source

Discovery of spectacular quasar-driven superbubbles in red quasars. [PDF]

Sci Adv, 2023
Shen L, Liu G, He Z, Zakamska NL, Glikman E, Greene JE, Hu W, Mou G, Wylezalek D, Rupke DSN.   +9 more
europepmc   +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

Optimal distribution of VLBI transmitters in the Galileo space segment for frame ties. [PDF]

Earth Planets Space, 2023
Wolf H, Böhm J.
europepmc   +1 more source

The Detection Rate of Associated Mg ii Absorption Lines in Quasars Depends on Their Radio Emission

The Astrophysical Journal
In active galactic nuclei, jet-driven feedback plays a significant role in influencing the properties of gas within their host galaxy and the circumgalactic medium.
Zhi-Fu Chen, Luis C. Ho
doaj   +1 more source