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We have observed seven powerful FR2 radiogalaxies and seven quasars with the Spitzer IRS. Both samples are comparable in both, redshift range and isotropic 178 Hz luminosity. Both samples are found to have similar distributions in the…

Astrophysics · Physics 2007-05-23 Bernhard Schulz , Ralf Siebenmorgen , Martin Haas , Endrik Kruegel , Rolf Chini

Quasars, as the most luminous persistent sources in the Universe, have broad applications for cosmological studies. In particular, they can be employed to directly measure the expansion history of the Universe, similarly to SNe Ia. The…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-02 J. Modzelewska , B. Czerny , M. Bilicki , K. Hryniewicz , M. Krupa , F. Petrogalli , W. Pych , A. Kurcz , A. Udalski

We present the results of K-band imaging polarimetry of seven 3CR radio galaxies at redshifts (z) between 0.7 and 1.2. We find strong evidence for polarization in three sources: 3C 22, 3C 41 and 3C 114. Of these, 3C 41 shows strong evidence…

Astrophysics · Physics 2009-10-30 G. Leyshon , Stephen A. Eales

We have made high-quality measurements of the polarization spectra of 13 FR II radio galaxies and taken polarization images for 11 of these with the Keck telescopes. Seven of the eight narrow-line radio galaxies (NLRG) are polarized, and…

Astrophysics · Physics 2009-10-31 M. H. Cohen , P. M. Ogle , H. D. Tran , R. W. Goodrich , J. S. Miller

Using a sample of 166 projected quasar pairs we investigate the influence of active galactic nuclei on the circumgalactic medium (CGM) of the quasar host galaxies probed using strong Mg II absorption (i.e., $W_{2796}\ge 1\dot{A}$) at impact…

Astrophysics of Galaxies · Physics 2026-02-11 Paryag Sharma , Raghunathan Srianand , Hum Chand , Labanya Kumar Guha

We report the serendipitous discovery of several unresolved X-ray sources lying in the prominent spiral arms of the galaxy KUG 0214-057 in XMM-Newton observations. The location of these X-ray sources strongly suggests that at least three,…

Astrophysics · Physics 2009-11-11 M. G. Watson , T. P. Roberts , M. Akiyama , Y. Ueda

Using the Spitzer Space Telescope, we have obtained rest frame 9-16mu spectra of 11 quasars and 9 radio galaxies from the 3CRR catalog at redshifts 1.0<z<1.4. This complete flux-limited 178MHz-selected sample is unbiased with respect to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 C. Leipski , M. Haas , S. P. Willner , M. L. N. Ashby , B. J. Wilkes , G. G. Fazio , R. Antonucci , P. Barthel , R. Chini , P. Ogle , R. Siebenmorgen , F. Heymann

Much effort has been done in order to better understand the active galactic nuclei mechanisms behind the relativistic jets observed in radio-loud sources. These phenomena are commonly seen in luminous objects with intermediate/high redshift…

Astrophysics of Galaxies · Physics 2022-05-31 A. Deconto-Machado , A. del Olmo Orozco , P. Marziani

We report the serendipitous discoveries of companion galaxies to two high-redshift quasars. SDSS J025617.7+001904 is a z=4.79 quasar included in our recent survey of faint quasars in the SDSS Stripe 82 region. The initial MMT slit…

Unlike at lower redshift, where there is a 40% detection rate, surveys for 21-cm absorption arising within the hosts of z > 1 radio galaxies and quasars have been remarkably unsuccessful. Curran et al.(2008) suggest that this is due to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 S. J. Curran , M. T. Whiting , E. M. Sadler , C. Bignell

Studying quasars at the highest redshifts can constrain models of galaxy and black hole formation, and it also probes the intergalactic medium in the early universe. Optical surveys have to date discovered more than 60 quasars up to z~6.4,…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 B. P. Venemans , J. R. Findlay , W. J. Sutherland , G. De Rosa , R. G. McMahon , R. Simcoe , E. A. Gonzalez-Solares , K. Kuijken , J. R. Lewis

The feedback from galactic outflows is thought to play an important role in shaping the gas content, star formation history, and ultimately the stellar mass function of galaxies. Here we present evidence for massive molecular outflows…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Aeree Chung , Min S. Yun , Gopal Naraynan , Mark Heyer , Neal R. Erickson

We have been carrying out a successful observational programme targeted at finding the highly obscured quasars that are thought to be the main contributors to the hard X-ray background. Out of 56 sources so far studied with optical and…

Astrophysics · Physics 2015-06-24 C. S. Crawford , P. Gandhi , A. C. Fabian

Odd Radio Circles (ORCs) are unexpected faint circles of diffuse radio emission discovered in recent wide deep radio surveys. They are typically about one arcmin in diameter, and may be spherical shells of synchrotron emission about a…

Astrophysics of Galaxies · Physics 2021-11-03 Ray P. Norris , Evan Crawford , Peter Macgregor

Active galaxies are the most powerful engines in the Universe for converting gravitational energy into radiation, and radio galaxies and radio-loud quasars are highly luminous and can be detected across the Universe. The jets that…

Astrophysics · Physics 2007-05-23 E. Belsole , D. M. Worrall , M. J. Hardcastle

We present a new redshift survey, the 2dF Quasar Dark Energy Survey pilot (2QDESp), which consists of ${\approx}10000$ quasars from ${\approx}150$ deg$^2$ of the southern sky, based on VST-ATLAS imaging and 2dF/AAOmega spectroscopy.…

In a multi-wavelength survey of $13$ quasars at $5.8\lesssim z\lesssim6.5$, that were pre-selected to be potentially young, we find five objects with extremely small proximity zone sizes that may imply UV-luminous quasar lifetimes of…

Chandra observations of a complete, flux-limited sample of 38 high-redshift (1<z<2), low-frequency selected (and so unbiased in orientation) 3CRR radio sources are reported. The sample includes 21 quasars (= broad line radio galaxies) and…

We examine the consistency of the unified scheme of FR II-type radio galaxies and quasars with their observed number and size distributions in the 3CRR sample. We separate the low-excitation galaxies from the high-excitation ones, as the…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-09 Ashok K. Singal

Deep optical images have been gathered for a nearly complete sample of radio galaxies from the Revised 3rd Cambridge (3CR) Catalog in the redshift range 0.15 < z < 0.65. Total and nuclear magnitudes and colors have been extracted. The…

Astrophysics · Physics 2009-11-07 Michael Harvanek , E. Ellingson , John T. Stocke
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