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We present rest-frame UV and Ly-alpha images of spatially-resolved structures around five high-redshift radio-loud quasars obtained with the WFPC2 camera on the Hubble Space Telescope. We find that all five quasars are extended and this…

GHz-peaked spectrum (GPS) radio sources are thought to be young objects which later evolve into FR-I and FR-II radio galaxies. We have used the Australia Telescope 20GHz (AT20G) survey catalogue to select a uniform sample of GPS sources…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Paul J. Hancock , Steven J. Tingay , Elaine M. Sadler , Chris Phillips , Adam T. Deller

Seyfert and LINER galaxies are known to exhibit compact radio emission on $\sim$ 10 to 100 parsec scales, but larger Kiloparsec-Scale Radio structures (KSRs) often remain undetected in sub-arcsec high resolution observations. We investigate…

Astrophysics of Galaxies · Physics 2014-10-13 Veeresh Singh , C. H. Ishwara-Chandra , Yogesh Wadadekar , Alexandre Beelen , Preeti Kharb

Archival Hubble Space Telescope WFPC2 images were used to search for optical emission associated with the radio jets of a number of luminous quasars. From this search, we report new optical hotspot detections in the well-known blazar…

Astrophysics · Physics 2009-11-10 C. C. Cheung , J. F. C. Wardle , T. Chen

We present multi-frequency radio data for a sample of narrow-line Seyfert 1 galaxies. We first focus on the sub-class of gamma-ray emitting narrow-line Seyfert 1 galaxies, studying the long-term radio variability of five sources and…

Astrophysics of Galaxies · Physics 2024-12-10 Xi Shao , Philip G. Edwards , Jamie Stevens , Minfeng Gu , Timothy J. Galvin , Minh T. Huynh

In classifying the ensemble of powerful extragalactic radio sources, considerable evidence has accumulated that radio galaxies and quasars are orientation-dependent manifestations of the same parent population: massive spheroidal galaxies…

We study the quasi-simultaneous near-IR, optical, UV, and X-ray photometry of eleven gamma-ray selected blazars for which redshift estimates larger than 1.2 have been recently provided. Four of these objects turn out to be high-power…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 P. Padovani , P. Giommi , A. Rau

We present a catalogue of 349 giant radio sources (GRSs including both galaxies and quasars). The database contains all giants known to date from the literature. These GRSs cover the redshift range of 0.016$<$z$<$3.22 and include radio…

Astrophysics of Galaxies · Physics 2018-10-10 A. Kuźmicz , M. Jamrozy , K. Bronarska , K. Janda-Boczar , D. J. Saikia

Six cases of fast radio bursts (FRBs) have recently been discovered. The FRBs are bright (~0.1 - 1 Jy) and brief (~ 1 ms) pulses of radio emission with dispersion measures (DMs) that exceed Galactic values, and hence FRBs have been…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Abraham Loeb , Yossi Shvartzvald , Dan Maoz

Infrared-faint radio sources (IFRS) are objects that have flux densities of several mJy at 1.4GHz, but that are invisible at 3.6um when using sensitive Spitzer observations with uJy sensitivities. Their nature is unclear and difficult to…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Enno Middelberg , Ray P. Norris , Christopher A. Hales , Nick Seymour , Melanie Johnston-Hollitt , Minh T. Huynh , Emil Lenc , Minnie Y. Mao

The Very Large Array Sky Survey (VLASS) is observing the entire sky north of $-40^{\circ}$ in the S-band ($2<\nu<4\,$GHz), with the highest angular resolution ($2''.5$) of any all-sky radio continuum survey to date. VLASS will cover its…

Eighteen days of MERLIN data and 42 hours of A-array VLA data at 1.4 GHz have been combined to image a 10-arcmin field centred on the Hubble Deep and Flanking Fields (HDF and HFF). A complete sample of 92 radio sources with 1.4-GHz flux…

We present high-resolution, high-sensitivity upgraded Giant Metrewave Radio Telescope observations of the Coma cluster (A1656) at 250-500 MHz and 550-850 MHz. At 250-500 MHz, 135 sources have extensions $>$ 0.45 arcmin (with…

We identified a large sample of radio quasars, including those with complex radio morphology, from the Sloan Digital Sky Survey (SDSS) and the Faint Images of Radio Sky at Twenty-cm (FIRST). Using this sample, we inspect previous radio…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-21 Yu Lu , Tinggui Wang , Hongyan Zhou , Jian Wu

[Abridged] Physical and evolutionary properties of the sub-mJy radio population are not entirely known. The radio/optical analysis of the ATESP 5 GHz sample has revealed a significant class of compact flat/inverted radio-spectrum sources…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 I. Prandoni , H. R. de Ruiter , R. Ricci , P. Parma , L. Gregorini , R. D. Ekers

A complete sample of 96 faint ($S > 0.5$ mJy) radio galaxies is selected from the Tenth Cambridge (10C) survey at 15.7~GHz. Optical spectra are used to classify 17 of the sources as high-excitation or low-excitation radio galaxies (HERGs…

Astrophysics of Galaxies · Physics 2016-08-31 Imogen H. Whittam , Julia M. Riley , David A. Green , Matt J. Jarvis

We analyzed two 1996 observations of the Galactic Microquasar GRS 1915+105 taken with the Proportional Counter Array on board the Rossi X-ray Timing Explorer. We focus on the properties of the high-frequency QPO as a function of the `dip'…

Astrophysics · Physics 2009-11-06 T. Belloni , Mariano Mendez , Celia Sanchez-Fernandez

We have measured the sub-milli-arcsecond structure of 274 extragalactic sources at 24 and 43 GHz in order to assess their astrometric suitability for use in a high frequency celestial reference frame (CRF). Ten sessions of observations with…

We present 1-7 GHz high-resolution radio imaging (VLA and e-MERLIN) and spatially-resolved ionized gas kinematics for ten z<0.2 type~2 `obscured' quasars (log [L(AGN)/(erg/s)]>~45) with moderate radio luminosities (log…

We use near infrared integral field unit (IFU) spectroscopy to search for H$\alpha$ emission associated with star formation in a sample of 28 heavily reddened ($E(B-V)\simeq$0.5-1.9), hyperluminous ($log(L_{bol}/ergs^{-1})\simeq$47-48)…

Astrophysics of Galaxies · Physics 2016-04-06 Susannah Alaghband-Zadeh , Manda Banerji , Paul C. Hewett , Richard G. McMahon