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Related papers: Quasar Radio Structure in Cluster Environments

200 papers

Volonteri et al. (2011) found that the number of radio-loud quasars above redshift 4 calculated from the luminosity function (based upon Swift/BAT observations) is much smaller than the number estimated from the known high-redshift beamed…

Astrophysics of Galaxies · Physics 2019-10-25 K. É. Gabányi , S. Frey , Z. Paragi , H. Cao , T. An , L. I. Gurvits , T. Sbarrato , K. Perger , K. Rozgonyi , Gy. Mező

Radio halos and relics are diffuse radio sources found in galaxy clusters showing significant substructure at X-ray wavelengths. These sources provide important information about non-thermal processes taking place in the ICM. Until now only…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 R. J. van Weeren , M. Bruggen , H. J. A. Rottgering , M. Hoeft , S. E. Nuza , H. T. Intema

VLBA observations at 18 cm are presented for 28 Compact Steep-spectrum radio Sources (CSSs) from the B3-VLA CSS sample. These sources were unresolved in previous VLA observations at high frequencies or their brightness distribution was…

Astrophysics · Physics 2009-11-07 D. Dallacasa , S. Tinti , C. Fanti , R. Fanti , L. Gregorini , C. Stanghellini , M. Vigotti

Broad absorption line quasars (BAL QSOs) belong to a class of objects not well-understood as yet. Their UV spectra show BALs in the blue wings of the UV resonance lines, owing to ionized gas with outflow velocities up to 0.2 c. They can…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-17 G. Bruni , D. Dallacasa , K. -H. Mack , F. M. Montenegro-Montes , J. I. González-Serrano , J. Holt , F. Jiménez-Luján

We investigate the sample of 213 GPS sources selected from simultaneous multi-frequency 1-22 GHz observations obtained with RATAN-600 radio telescope. We use publicly available data to characterize parsec-scale structure of the selected…

Astrophysics of Galaxies · Physics 2009-01-23 K. V. Sokolovsky , Y. Y. Kovalev

We investigate potential correlations between radio source counts (after background corrections) of 22 Galactic globular clusters (GCs) from the MAVERIC survey, and stellar encounter rates ($\Gamma$) and masses ($M$) of the GCs. Applying a…

The presence of large-scale magnetic fields and ultra-relativistic electrons in the intra-cluster medium (ICM) is confirmed through the detection of diffuse radio synchrotron sources, so-called radio halos and relics. Due to their…

In this work, we calculated the sizes of unresolved X-ray emission regions in three gravitationally lensed radio-loud quasars, B\,1422+231, MG\,J0414+0534 and Q\,0957+561, using a combination of imaging and spectral analysis on the X-ray…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-12 Mustafa Burak Dogruel , Xinyu Dai , Eduardo Guerras , Matthew Cornachione , Christopher W. Morgan

Diffuse radio sources associated with the intra-cluster medium are direct probes of the cosmic ray electrons and magnetic fields. We report the discovery of a diffuse radio source in the galaxy cluster RXCJ0232.2-4420 (SPT-CL J0232-4421,…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-22 Ruta Kale , Krishna M. Shende , Viral Parekh

The GLOSTAR survey studies star formation with the VLA and the Effelsberg 100m telescope in the Galactic plane (-2d<l<60d; |b|<1d) and the Cygnus X region with unprecedented sensitivity in both flux density (~50uJy/beam) and the capability…

We present the results of EVN+MERLIN VLBI polarization observations of 8 Broad Absorption Line (BAL) quasars at 1.6 GHz, including 4 LoBALs and 4 HiBALs with either steep or flat spectra on VLA scales. Only one steep-spectrum source,…

Astrophysics · Physics 2009-11-13 Y. Liu , D. R. Jiang , T. G. Wang , F. G. Xie

We present 8.4 GHz VLA A-array and 1.4 GHz VLBA results on the radio continuum emission from the highest redshift radio-loud quasar known to date, the $z=6.12$ QSO J1427+3312. The VLA observations show an unresolved steep spectrum source…

Astrophysics · Physics 2015-06-11 E. Momjian , C. L. Carilli , I. D. McGreer

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from…

Astrophysics · Physics 2009-10-31 D. J. Saikia , S. Jeyakumar , C. J. Salter , P. Thomasson , R. E. Spencer , F. Mantovani

We have formed a complete sample of 26 low redshift (z < 0.3) giant radio galaxies (GRGs) from the WENSS survey, selected at flux densities above 1 Jy at 325 MHz. We present 10.5-GHz observations with the 100-m Effelsberg telescope of 18…

New images of 7 radio halos and relics, obtained with the Very Large Array at 20 or 90 cm, are presented here. The existence of a cluster-wide radio halo in the clusters A 665 and CL 0016+16 is confirmed. Both these clusters share the…

Astrophysics · Physics 2009-10-31 G. Giovannini , L. Feretti

We present the method and first results of a survey for high-redshift (z>3) radio-loud quasars, which is based on optical identifications of 2902 flat-spectrum radio sources with S(5GHz)>= 25mJy. The radio sample was defined over a 1600 sq…

Astrophysics · Physics 2009-10-30 I. M. Hook , R. H. Becker , R. G. McMahon , R. L. White

Over half the 3CRR sample of radio galaxies and quasars has been observed in X-rays with ROSAT pointed observations, and we present results from these observations, discussing many of the sources in detail. The improved spatial resolution…

Astrophysics · Physics 2009-10-31 M. J. Hardcastle , D. M. Worrall

Quasars at redshifts $z>6$ are an excellent probe of the formation and evolution of supermassive black holes in the early Universe. The population of radio-luminous quasars is of particular interest, as such quasars could potentially be…

Astrophysics of Galaxies · Physics 2024-02-15 Pascal M. Keller , Nithyanandan Thyagarajan , Ajay Kumar , Nissim Kanekar , Gianni Bernardi

We present the results of Chandra observations of six radio-loud quasars (RLQs) and one optically bright radio-quiet quasar (RQQ) at z = 4.1-4.4. These observations cover a representative sample of RLQs with moderate radio-loudness (R ~…

Astrophysics · Physics 2009-11-10 L. C. Bassett , W. N. Brandt , D. P. Schneider , C. Vignali , G. Chartas , G. P. Garmire

We present ATCA radio images of the globular cluster 47 Tucanae made at 1.4 and 1.7 GHz and provide an analysis of the radio sources detected within 5 arcmin of the cluster centre. 11 sources are detected, most of which are clustered about…

Astrophysics · Physics 2009-10-31 D. McConnell , J. G. Ables