Results 71 to 80 of about 10,418 (177)

VLBA Observations ofz>4 Radio-loud Quasars

The Astronomical Journal, 2004
We present high resolution (< 20 mas) observations of the radio continuum emission at 1.4 GHz from three high-redshift quasars: J1053-0016 (z=4.29), 1235-0003 (z=4.69), and J0913+5919 (z=5.11), thereby doubling the number of z > 4 radio-loud quasars that have been imaged at mas resolution.
Momjian, Emmanuel, Petric, Andreea O., Carilli, Christopher L.   +2 more
openaire   +2 more sources

Impact of Radio-mode Feedback on the Covering Fraction of the Circumgalactic Medium of Quasars

The Astrophysical Journal
Utilizing data from the Low-Frequency Array Two-meter Sky Survey and the Sloan Digital Sky Survey, we assemble a sample of 1469 projected quasar pairs with detected radio emissions from foreground quasars, as well as a control sample of 5846 pairs ...
Wen-Qiang Liang, Zhi-fu Chen, Rui-Jing Lu, Jing Li, Zhe-Geng Chen   +4 more
doaj   +1 more source

Black Hole Mass Estimates of Radio Selected Quasars

, 2002
The black hole (BH) mass in the centre of AGN has been estimated for a sample of radio-selected flat-spectrum quasars to investigate the relationship between BH mass and radio properties of quasars. We have used the virial assumption with measurements of
A. Y. K. N. Oshlack, Drinkwater M. J., Francis P. J., Kormendy J., M. T. Whiting, R. L. Webster, Wilkes B. J.   +6 more
core   +1 more source

Optical off-nuclear spectra of quasar hosts and radio galaxies [PDF]

, 2000
We present optical (~3200A to ~9000A) off-nuclear spectra of 26 powerful active galaxies in the redshift range 0.1 < z < 0.3, obtained with the Mayall and William Herschel 4-meter class telescopes.
Boroson, Todd, Dunlop, James S., Hughes, David H., Kukula, Marek J.   +3 more
core   +3 more sources

CONSTRAINING THE RADIO-LOUD FRACTION OF QUASARS ATz> 5.5 [PDF]

The Astrophysical Journal, 2015
Accepted for publication in ApJ. 3 Figures.
E. Bañados, B. P. Venemans, E. Morganson, J. Hodge, R. Decarli, F. Walter, D. Stern, E. Schlafly, E. P. Farina, J. Greiner, K. C. Chambers, X. Fan, H-W. Rix, W. S. Burgett, P. W. Draper, J. Flewelling, N. Kaiser, N. Metcalfe, J. S. Morgan, J. L. Tonry, R. J. Wainscoat   +20 more
openaire   +5 more sources

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

Quasar Clustering from SDSS DR5: Dependences on Physical Properties

, 2008
Using a homogenous sample of 38,208 quasars with a sky coverage of $4000 {\rm deg^2}$ drawn from the SDSS Data Release Five quasar catalog, we study the dependence of quasar clustering on luminosity, virial black hole mass, quasar color, and radio ...
Abazajian, Abazajian, Adelberger, Adelman-McCarthy, Andrew J. Connolly, Basilakos, Blanton, Coil, Cole, Constantin, Courteau, Croft, Croton, Daniel E. Vanden Berk, David H. Weinberg, Donald P. Schneider, Eisenstein, Fan, Ferrarese, Ferrarese, Francesco Shankar, Gao, Gebhardt, Gordon T. Richards, Gunn, Gunn, Haiman, Hennawi, Ho, Hogg, Hopkins, Hopkins, Hopkins, Hopkins, Jiang, Jing, Joseph F. Hennawi, King, Kollmeier, Kormendy, Lidz, Lupton, Magorrian, Martini, Michael A. Strauss, Mo, Myers, Myers, Myers, Myers, Neta A. Bahcall, Nicholas P. Ross, Padmanabhan, Padmanabhan, Patrick B. Hall, Pier, Reichard, Richards, Richards, Richards, Richstone, Robert J. Brunner, Ross, Schlegel, Schlegel, Schneider, Shankar, Shankar, Shen, Shen, Shen, Shen, Shen, Silk, Smith, Spergel, Stoughton, Tinker, Tremaine, Vestergaard, Wechsler, Wetzel, Wyithe, Wyithe, Wyithe, Xiaohui Fan, Yen-Ting Lin, York, Yue Shen, Zehavi, Zel'dovich   +90 more
core   +1 more source

Disclosing the Radio Loudness Distribution Dichotomy in Quasars: An Unbiased Monte Carlo Approach Applied to the SDSS-FIRST Quasar Sample [PDF]

, 2012
We investigate the dichotomy in the radio loudness distribution of quasars by modelling their radio emission and various selection effects using a Monte Carlo approach. The existence of two physically distinct quasar populations, the radio-loud and radio-
B. C. Kelly, Blandford, E. Schinnerer, G. Zamorani, Garofalo, Hodge, Hughes, Ivezić, Ivezić, Ivezić, Jiang, Kimball, Kimball, Lacy, Laor, M. Baloković, Mahoney, Miller, Padovani, Peacock, Richards, Richards, Schinnerer, Schlegel, Schneider, Scoville, Sikora, Singal, Smolčić, Strittmatter, V. Smolčić, White, White, York, Ž. Ivezić   +34 more
core   +4 more sources

SwiftObservations of High‐Redshift Radio‐loud Quasars [PDF]

The Astrophysical Journal, 2007
We report on Swift observations of four z>2 radio-loud quasars (0212+735, 0537-286, 0836+710, and 2149-307), classified as blazars. The sources, well-known emitters at soft-medium X-rays, were detected at >5sigma with the BAT experiment in 15-150 keV.
Sambruna, R. M., Tavecchio, F., Ghisellini, G., Donato, D., Holland, S. T., Markwardt, C. B., Tueller, J., Mushotzky, R. F.   +7 more
openaire   +2 more sources

A Sample of Quasars with Strong Nitrogen Emission Lines from the Sloan Digital Sky Survey [PDF]

, 2008
We report on 293 quasars with strong NIV] lambda 1486 or NIII] lambda 1750 emission lines (rest-frame equivalent width > 3 \AA) at 1.7 < z < 4.0 selected from the Sloan Digital Sky Survey (SDSS) Fifth Data Release.
Fan, Xiaohui, Jiang, Linhua, Vestergaard, M.   +2 more
core   +2 more sources