Results 101 to 110 of about 515 (214)

A range of time delays for the double quasar 0957 + 561 A, B

The Astrophysical Journal, 1980
We have extended the complex formalism of Bourassa and Kantowski for a transparent gravitational lens to a multilens situation. By using a grid of assumed positions for the cluster center within its measured error box, we have then calculated a range of possible time delays between the two images, A and B. The results indicate a range from 0.03 yr to 1.
C. C. Dyer, R. C. Roeder
openaire   +1 more source

Outflow and hot dust emission in high redshift quasars [PDF]

, 2013
Correlations of hot dust emission with outflow properties are investigated, based on a large z similar to 2 non-broad absorption line quasar sample built from the Wide-field Infrared Survey and the Sloan Digital Sky Survey data releases.
Wang, Tinggui, Kai Zhang, Xing, Feijun, Shaohua Zhang, Zhang, Shaohua, Huiyuan Wang, Wang, Huiyuan, Zhou, Hongyan, Feijun Xing, Hongyan Zhou, Zhang, Kai, Tinggui Wang   +11 more
core  

Spectroastrometry and Reverberation Mapping of Active Galactic Nuclei. I. The Hβ Broad-line Region Structure and Black Hole Masses of Five Quasars

The Astrophysical Journal
We conduct a reverberation mapping (RM) campaign to spectroscopically monitor a sample of selected bright active galactic nuclei with large anticipated broad-line region (BLR) sizes adequate for spectroastrometric (SA) observations by the GRAVITY ...
Yan-Rong Li, Chen Hu, Zhu-Heng Yao, Yong-Jie Chen, Hua-Rui Bai, Sen Yang, Pu Du, Feng-Na Fang, Yi-Xin Fu, Jun-Rong Liu, Yue-Chang Peng, Yu-Yang Songsheng, Yi-Lin Wang, Ming Xiao, Shuo Zhai, Hartmut Winkler, Jin-Ming Bai, Luis C. Ho, Romain G. Petrov, Jesús Aceituno, Jian-Min Wang, SARM Collaboration   +21 more
doaj   +1 more source

Widespread Detection of Aromatic and Aliphatic Emission in the Dual Quasar J0749+2255 at Cosmic Noon

The Astrophysical Journal Letters
Based on the integral field observations made with the Mid Infrared Instrument on board the James Webb Space Telescope (JWST), we report a widespread detection of aromatic and aliphatic hydrocarbon emission at rest-frame 3.3 and 3.4 μ m in SDSS J074922 ...
C. E. Mentzer, Aigen Li, X. J. Yang
doaj   +1 more source

The Influence of Microlensing on Time Delay Determinations in Double‐imaged Quasars

The Astrophysical Journal, 1998
The lag associated with the main peak of the cross-correlation function of the two light curves arriving from a double-imaged quasar is usually identified with the time delay between the components. However, short-timescale microlensing events can independently modify the light curve of each component, and when strong microlensing is present, the ...
Luis Julian Goicoechea, Alejandro Oscoz, Evencio Mediavilla, Jesus Buitrago, Miquel Serra‐Ricart   +4 more
openaire   +1 more source

Minor contribution of quasars to ionizing photon budget at z 3c 6: update on quasar luminosity function at the faint end with subaru/suprime-Cam [PDF]

, 2017
We constrain the quasar contribution to the cosmic reionization based on our deep optical survey of z ~ 6 quasars down to z R = 24.15 using Subaru/Suprime-Cam in three UKIDSS-DXS fields covering 6.5 deg2. In Kashikawa et al.
Kashikawa, Nobunari, Uchiyama, Hisakazu, Imanishi, Masatoshi, Ishikawa, Shogo, Matsuoka, Yoshiki, Tang, Ji-jia, Toshikawa, Jun, Tanaka, Masayuki, Kikuta, Satoshi, Im, Myungshin, Harikane, Yuichi, Ouchi, Masami, Onoue, Masafusa, Niino, Yuu, Willott, Chris J., Furusawa, Hisanori, Hibon, Pascale, Ono, Yoshiaki, Nagao, Tohru   +18 more
core   +1 more source

Varstrometry for Dual Active Galactic Nuclei Using Radio Interferometry: VaDAR with the VLBA

The Astrophysical Journal
Multiple active galactic nuclei (multi-AGN) are a known result of galaxy mergers. Therefore, they are an important tool for studying the formation and dynamical evolution of galaxies and supermassive black holes. A novel method for the selection of multi-
Emma Schwartzman, Paula Fudolig, Tracy E. Clarke, Kristina Nyland, Nathan J. Secrest, Ryan W. Pfeifle, Henrique Schmitt, Shobita Satyapal, Barry Rothberg   +8 more
doaj   +1 more source

Active Galactic Nuclei and Host Galaxies in COSMOS-Web. II. First Look At the Kiloparsec-scale Dual and Offset AGN Population

The Astrophysical Journal
Kiloparsec-scale dual and offset active galactic nuclei (AGNs) are signposts of accreting supermassive black holes (SMBHs) triggered during late-stage galaxy mergers, offering crucial insights into the coevolution of SMBHs and galaxies. However, robustly
Junyao Li, Ming-Yang Zhuang, Yue Shen, Marta Volonteri, Nianyi Chen, Tiziana Di Matteo   +5 more
doaj   +1 more source

The Role of Galaxies and Quasars in Reionising the High Redshift Intergalactic Medium [PDF]

, 2020
Only one billion years after the Big Bang, the neutral hydrogen in the intergalactic medium had been completely ionised. This last phase transition of the Universe known as the epoch of reionisation is one of the frontiers in astrophysics.
Meyer, Romain A.
core  

The Gamma-Ray Luminosity Function of Flat-spectrum Radio Quasars

The Astrophysical Journal
We have utilized the largest sample of gamma-ray-selected Fermi flat-spectrum radio quasars (FSRQs) ever used (519 sources) to construct the luminosity function and its evolution through cosmic history. In addition to spanning large redshift (0 
Garima Rajguru, L. Marcotulli, M. Ajello, M. Di Mauro, M. Urry   +4 more
doaj   +1 more source