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Related papers: Alignment of quasar polarizations with large-scale…

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The relation between quasar variability and parameters such as luminosity and redshift has been a matter of hot debate over the last few years with many papers on the subject. Any correlations which can be established will have a profound…

Astrophysics · Physics 2009-10-31 M. R. S. Hawkins

Our objective is to investigate the distribution of dust and associated large-scale structures of the Galaxy using optical linear polarization measurements of various open clusters located at different distances in the Galactic anticenter…

Astrophysics of Galaxies · Physics 2024-10-02 Namita Uppal , Shashikiran Ganesh , Vincent Pelgrims , Santosh Joshi , Mrinmoy Sarkar

We analyze the available sample of double quasars, and investigate their physical properties. Our sample comprises 85 pairs, selected from the Sloan Digital Sky Survey (SDSS). We derive physical parameters for the engine and the host, and…

Astrophysics · Physics 2011-02-11 Gary Foreman , Marta Volonteri , Massimo Dotti

We present total-intensity and linear-polarization observations made with the Very Large Array at $\lambda$20 and 6 cm of a representative sample of 42 radio galaxies and quasars selected from the Molonglo Complete Sample. The sources have…

Astrophysics · Physics 2009-10-31 C. H. Ishwara-Chandra , D. J. Saikia , V. K. Kapahi , P. J. McCarthy

We study quasar clustering on small scales, modeling clustering amplitudes using halo-driven dark matter descriptions. From 91 pairs on scales <35 kpc/h, we detect only a slight excess in quasar clustering over our best-fit large-scale…

Quasars are galaxies hosting accreting supermassive black holes; due to their brightness, they are unique probes of the early universe. To date, only few quasars have been reported at $z > 6.5$ ($<$800 Myr after the Big Bang). In this work,…

Whether or not $z \gtrsim 6$ quasars lie in the most massive dark-matter halos of the Universe is still a subject of dispute. While most theoretical studies support this scenario, current observations yield discordant results when they…

There is controversy about the measurement of statistical associations between bright quasars and faint, presumably foreground galaxies. We look at the distribution of galaxies around an unbiased sample of 63 bright, moderate redshift…

Astrophysics · Physics 2015-06-24 P. A. Thomas , R. L. Webster , M. J. Drinkwater

We have carried out multicolour imaging of a complete sample of radio-loud quasars at 0.6 < z < 1.1 and find groups or clusters of galaxies in the fields of at least 8 and possibly 13 of the 21 sources. There is no evidence for an evolution…

Astrophysics · Physics 2009-11-10 J. M. Barr , M. N. Bremer , J. C. Baker , M. D. Lehnert

We have used the very large JVAS/CLASS 8.4-GHz surveys of flat-spectrum radio sources to test the hypothesis that there is a systematic alignment of polarization position angle vectors on cosmological scales of the type claimed by…

Astrophysics · Physics 2009-06-23 S. A. Joshi , R. A. Battye , I. W. A. Browne , N. Jackson , T. W. B. Muxlow , P. N. Wilkinson

We investigate the environments of quasars such as number distribution of galaxies using a semi-analytic model which includes both galaxy and quasar formations based on the hierarchical clustering scenario. We assume that a supermassive…

Astrophysics · Physics 2014-12-02 Motohiro Enoki , Masahiro Nagashima , Naoteru Gouda

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

As is known, resonant scattering can distort the surface-brightness profiles of clusters of galaxies in X-ray lines. We demonstrate that the scattered line emission should be polarized and possibly detectable with near-future X-ray…

Astrophysics · Physics 2009-11-07 S. Sazonov , E. Churazov , R. Sunyaev

We present a systematic study of the circular polarization in pulsar integrated profiles, based on published polarization data. For core components, we find no significant correlation between the sense-change of circular polarization and…

Astrophysics · Physics 2009-10-30 J. L. Han , R. N. Manchester , R. X. Xu , G. J. Qiao

Gamma-ray emitting blazars have been the targets of many recent or ongoing monitoring programmes. The resulting multi-wavelength data archives are ideal for studying the quiescent and variable behaviour of the blazar PKS 2155-304. Here,…

High Energy Astrophysical Phenomena · Physics 2017-02-15 Nikki Pekeur , Russ Taylor , Renée Kraan-Korteweg

I report the detection of circular polarisation, associated with relativistic ejections, from the `microquasar' GRS 1915+105. I further compare detections and limits of circular polarisation and circular-to-linear polarisation ratios in…

Astrophysics · Physics 2009-11-07 Rob Fender

We review recent observations of circularly polarized radiation from AGN made with the VLBA and with the ATCA. We also discuss briefly the detections of the Galactic sources Sag A* and SS433. The origin of the circular polarization is still…

Astrophysics · Physics 2007-05-23 John F. C. Wardle , Daniel C. Homan

We present the first resolved observations of the 1.3mm polarized emission from the disk-like structure surrounding the high-mass protostar Cepheus A HW2. These CARMA data partially resolve the dust polarization, suggesting an uniform…

Solar and Stellar Astrophysics · Physics 2016-12-14 M. Fernández-López , I. W. Stephens , J. M. Girart , L. Looney , S. Curiel , D. Segura-Cox , C. Eswaraiah , S. -P. Lai

We present first results from our study of the properties of ~400 low redshift (z < 0.5) quasars, based on a large homogeneous dataset derived from the Stripe 82 area of the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7). For this sky…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-08 Jari Kotilainen , Renato Falomo , Daniela Bettoni , Kalle Karhunen , Michela Uslenghi

Recently a data set containing linear and circular polarisation information of a collection of six hundred pulsars has been released. The operative radio wavelength for the same was 21 cm. Pulsars radio emission process is modelled either…

High Energy Physics - Phenomenology · Physics 2019-11-11 Karam Chand , Subhayan Mandal
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