Results 111 to 120 of about 83,297 (253)

A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity

, 2007
(Abridged) We develop a model for the cosmological role of mergers in the evolution of starbursts, quasars, and spheroidal galaxies. Combining halo mass functions (MFs) with empirical halo occupation models, we calculate where major galaxy-galaxy mergers
Athanassoula E., Bower R. G., Combes F., da Angela J., Dušan Kereš, Gao L., Kormendy J., Krivitsky D. S., Lars Hernquist, Li C., Lynden-Bell D., Mo H. J., Pfenniger D., Philip F. Hopkins, Richstone D., Salviander S., Saunders W., Shakura N. I., Soltan A., Thomas J. Cox, Weinmann S. M., White S. D. M.   +21 more
core   +1 more source

Wavelengths of [Fe II] from quasar J110325-264515 for a study of space-time variations in the fine-structure constant

Results in Physics, 2019
We report a new stringent limit relating to the space-time variation in the fine-structure constant α=e24πε0ℏc from an analysis of quasar J110325-264515 towards zabs=1.8389. We find Δα/α=(1.56±1.78)×10-6 from a comparison of laboratory wavelengths of [Fe
T.D. Le
doaj   +1 more source

Variability-selected Quasars behind the Small Magellanic Cloud [PDF]

, 2003
A. Dobrzycki, L. M. Macri, K. Z. Stanek, P. J. Groot   +3 more
openalex   +1 more source

Some Constraints on Quasar Progenitors and Quasar Evolution [PDF]

Symposium - International Astronomical Union, 1986
There is strong evidence that quasars are powered by the gravitational energy released by in fall of matter into a compact supermassive object which is most likely a black hole with mass M>106 to 109MO. The question then arises as to how such massive black holes came to be formed. What sort of objects were the progenitors?
openaire   +1 more source

Ultra-compact structure in intermediate-luminosity radio quasars: building a sample of standard cosmological rulers and improving the dark energy constraints up to z ~ 3 [PDF]

, 2017
Shuo Cao, Xiaogang Zheng, Marek Biesiada, Jingzhao Qi, Yun Chen, Zong-Hong Zhu   +5 more
openalex   +1 more source

Modeling the cosmological co-evolution of supermassive black holes and galaxies: II. The clustering of quasars and their dark environment

, 2009
We use semi-analytic modeling on top of the Millennium simulation to study the joint formation of galaxies and their embedded supermassive black holes.
Adelberger, Alvarez, Baes, Bajtlik, Barnes, Best, Bromm, Bullock, Carswell, Cattaneo, Cattaneo, Coil, Colberg, Cole, Cowie, Croom, Croom, Croton, Croton, da Ângela, De Lucia, Di Matteo, Elvis, Enzo Branchini, Fan, Fan, Federico Marulli, Ferrarese, Ferrarese, Ferrarese, Fine, Graham, Grazian, Haehnelt, Haiman, Hasinger, Heckman, Heger, Hopkins, Hopkins, Hopkins, Häring, Kauffmann, Kirkman, Kollmeier, Koushiappas, Koushiappas, Lauro Moscardini, Li, Lidz, Loeb, Madau, Magorrian, Malbon, Marconi, Marconi, Martini, Martini, Marulli, Marulli, Marulli, Marulli, Merloni, Merloni, Mo, Monaco, Myers, Netzer, Peacock, Porciani, Ricotti, Ripamonti, Ross, Ross, Sesana, Shakura, Shankar, Shankar, Shen, Shen, Sheth, Silk, Silvia Bonoli, Simon D. M. White, Soltan, Spergel, Springel, Springel, Springel, Steffen, Thacker, Tremaine, Ueda, Volker Springel, White, York, Yu   +96 more
core   +1 more source

CatNorth: An Improved Gaia DR3 Quasar Candidate Catalog with Pan-STARRS1 and CatWISE

The Astrophysical Journal Supplement Series
A complete and pure sample of quasars with accurate redshifts is crucial for quasar studies and cosmology. In this paper, we present CatNorth, an improved Gaia Data Release 3 (Gaia DR3) quasar candidate catalog with more than 1.5 million sources in the 3
Yuming Fu, Xue-Bing Wu, Yifan Li, Yuxuan Pang, Ravi Joshi, Shuo Zhang, Qiyue Wang, Jing Yang, FanLam Ng, Xingjian Liu, Yu Qiu, Rui Zhu, Huimei Wang, Christian Wolf, Yanxia Zhang, Zhi-Ying Huo, Y. L. Ai, Qinchun Ma, Xiaotong Feng, R. J. Bouwens   +19 more
doaj   +1 more source

ESTIMATING PHOTOMETRIC REDSHIFTS OF QUASARS VIA THEk-NEAREST NEIGHBOR APPROACH BASED ON LARGE SURVEY DATABASES [PDF]

, 2013
Yanxia Zhang, He Ma, Nanbo Peng, Yongheng Zhao, Xue-bing Wu   +4 more
openalex   +1 more source

Constraints on the relative sizes of intervening Mg II-absorbing clouds and quasar emitting regions

, 2012
Context: A significantly higher incidence of strong (rest equivalent width W_r > 1 {\AA}) intervening Mg II absorption is observed along gamma-ray burst (GRB) sight-lines relative to those of quasar sight-lines.
Hjorth, Jens, Lawther, Daniel, Malesani, Daniele, Paarup, Troels, Schmidt, Morten, Vestergaard, Marianne   +5 more
core   +1 more source

Overdensity of galaxies in the environment of quasar pairs [PDF]

, 2017
A. Sandrinelli, R. Falomo, A. Treves, R. Scarpa, M. Uslenghi   +4 more
openalex   +1 more source