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The Hertz and SCUBA polarimeters, working at 350 micron and 850 micron respectively, have measured the polarized emission in scores of Galactic clouds. Of the clouds in each dataset, 17 were mapped by both instruments with good polarization…

Astrophysics of Galaxies · Physics 2015-06-04 John E. Vaillancourt , Brenda C. Matthews

A tendency for the axes of double-lobed radio quasars to be aligned with the electric vectors of optical polarization in the active galactic nuclei is well-known. However, the origin of the polarization and reason behind its correlation…

Astrophysics · Physics 2009-10-31 Gary D. Schmidt , Paul S. Smith

In this Paper we present a clustering analysis of QSOs as a function of luminosity over the redshift range z=0.3-2.9. We use a sample of 10566 QSOs taken from the preliminary data release catalogue of the 2dF QSO Redshift Survey (2QZ). We…

Astrophysics · Physics 2009-11-07 Scott M. Croom , B. J. Boyle , N. S. Loaring , L. Miller , P. J. Outram , T. Shanks , R. J. Smith

We report 87 previously unpublished optical linear polarization measurements of 86 quasars obtained in May and October 2008, and from April to July 2015 with the Focal Reducer and low-dispersion Spectrographs FORS1 and FORS2 attached to the…

Astrophysics of Galaxies · Physics 2018-11-28 D. Hutsemékers , B. Borguet , D. Sluse , V. Pelgrims

We present quasi-simultaneous multi-colour optical/near-IR photometry for 157 radio selected quasars, forming an unbiassed sub-sample of the Parkes Flat-Spectrum Sample. Data are also presented for 12 optically selected QSOs, drawn from the…

Astrophysics · Physics 2015-06-24 Paul J. Francis , Matthew T. Whiting , Rachel L. Webster

The evolution of quasar clustering is investigated with a new sample of 388 quasars with 0.3<z<=2.2, B<=20.5 and Mb<-23, selected over an area of 24.6 sq. deg. in the South Galactic Pole. Assuming a two-point correlation function of the…

Astrophysics · Physics 2009-10-30 Fabio La Franca , Paola Andreani , Stefano Cristiani

The relationship between variability, luminosity and redshift in the South Galactic Pole QSO sample is examined in an effort to disentangle the effects of luminosity and redshift in the amplitude of the optical variations. The…

Astrophysics · Physics 2015-06-24 R. Cid Fernandes , I. Aretxaga , R. Terlevich

We have analyzed the observed image separations of the gravitationally lensed images of QSOs for a possible correlation with the source redshift. Contrary to the previously noted anti-correlation based on a smaller data set, no correlation…

Astrophysics · Physics 2009-10-31 Pushpa Khare

Infrared observations of the Galactic center (GC) provide a unique opportunity to study stellar and bow-shock polarization effects in a dusty environment. The goals of this work are to present new Ks- and Lp-band polarimetry on an…

Astrophysics of Galaxies · Physics 2015-06-16 Rainer M. Buchholz , Gunther Witzel , Rainer Schoedel , Andreas Eckart

We present the galaxy-galaxy angular correlations as a function of photometric redshift in a deep-wide galaxy survey centered on the Hubble Deep Field South. Images were obtained with the Big Throughput Camera on the Blanco 4m telescope at…

We present images taken with the Wide Field Planetary Camera (WFPC-2) on the Hubble Space Telescope of 43 quasars selected from the 3CR radio catalog. The redshift range of the targets is large --- 0.3 < z < 2. These data were taken in the…

We present preliminary results from the 2-degree Field (2dF) QSO Redshift Survey currently under way at the Anglo-Australian Telescope. This survey aims to determine the redshifts of >25000 QSOs over a redshift range of 0.3<z<3.0 with the…

Astrophysics · Physics 2007-05-23 S. M. Croom , T. Shanks , B. J. Boyle , R. J. Smith , L. Miller , N. S. Loaring

The quest for structure indicators at earlier and earlier times in the evolution of the universe has led to the search for objects with ever higher redshifts. The Palomar Transit Grism Survey has produced a large sample of high redshift…

We demonstrate that high-redshift 1-Jansky radio sources are correlated with foreground IRAS galaxies on angular scales of several 10 arc minutes on a statistical significance level of up to 99.8\%. Based on a theoretical analysis published…

Astrophysics · Physics 2007-05-23 M. Bartelmann , P. Schneider

QSOs and radio-galaxies, together with the CMB, ``normal'' galaxies and clusters, represent the main source of information about the origin and evolution of the Large Scale Structure. They can be used either directly, as tracers of the…

Astrophysics · Physics 2007-05-23 S. Cristiani

Observations of QSOs at z ~ 5.7 - 6.4 show the appearance of Gunn-Peterson troughs around z ~ 6, and a change in the slope of the IGM optical depth tau(z) near z ~ 5.5. These results are interpreted as a signature of the end of the…

Astrophysics · Physics 2009-11-13 S. G. Djorgovski , M. Bogosavljevic , A. Mahabal

We analyse a sample of 69 QSOs which have been randomly selected in a complete sample of 104 QSOs (R<18, 0.142 < z < 0.198). 60 have been observed with the NTT/SUSI2 at La Silla, through two filters in the optical band (WB#655 and V#812),…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-22 Y. Letawe , G. Letawe , P. Magain

We address the question of whether massive red and blue galaxies trace the same large-scale structure at z~0.6 using the CMASS sample of galaxies from Data Release 12 of the Sloan Digital Sky Survey III. After splitting the catalog into…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-23 Anna Patej , Daniel Eisenstein

The study of absorptions along the lines of sight to bright high-$z$ QSOs is an invaluable cosmological tool that provides a wealth of information on the inter-/circum-galactic medium, Dark Matter, primordial elements, reionization,…

Instrumentation and Methods for Astrophysics · Physics 2020-01-08 Calderone G. , Boutsia K. , Cristiani S. , Grazian A. , Amorin R. , D'Odorico V. , Cupani G. , Fontanot F. , Salvato M

We use six different cosmological models to study the recently-released compilation of X-ray and UV flux measurements of 2038 quasars (QSOs) which span the redshift range $0.009 \leq z \leq 7.5413$. We find, for the full QSO data set, that…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Narayan Khadka , Bharat Ratra