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We present integrated polarization properties of nearby spiral galaxies at 4.8 GHz, and models for the integrated polarization of spiral galaxy disks as a function of inclination. Spiral galaxies in our sample have observed integrated…

天体物理学 · 物理学 2011-02-11 Jeroen M. Stil , Marita Krause , Rainer Beck , A. Russell Taylor

Polar-ring galaxies are photometrically and kinematically decoupled systems which are highly inclined to the major axis of the host galaxy. These objects have been explored since the 1970s, but the rarity of these systems has made such…

We have observed two blank fields of approximately 30 by 23 arcminutes using the William Herschel Telescope. The fields have been studied as part of the CNOC2 survey, and spectroscopic redshifts are available for 1125 galaxies in the two…

天体物理学 · 物理学 2009-11-07 H. Hoekstra , M. Franx , K. Kuijken , R. G. Carlberg , H. K. C. Yee

Using data from the HST Medium Deep Survey, a long-term Key Project, together with generically similar archived data, we have discovered evidence for weak gravitational `shear' of background field galaxies (I = 22 -- 26) in the vicinity of…

天体物理学 · 物理学 2015-06-24 R. E. Griffiths , S. Casertano , M. Im , K. U. Ratnatunga

Magnetic fields permeate the entire Galaxy and are essential to, for example, the regulation of several stages of the star formation process and cosmic ray transportation. Unraveling its properties, such as intensity and topology, is an…

We present results from deep, wideband, high spatial and spectral resolution observations of the nearby luminous radio galaxy Cygnus A with the Jansky Very Large Array. The high surface brightness of this source enables detailed…

We propose a new technique for weak gravitational lensing in the radio band making use of polarization information. Since the orientation of a galaxy's polarized emission is both unaffected by lensing and is related to the galaxy's…

宇宙学与河外天体物理 · 物理学 2015-05-18 Michael L. Brown , Richard A. Battye

We report a detection of the coherent distortion of faint galaxies arising from gravitational lensing by foreground structures. This ``cosmic shear'' is potentially the most direct measure of the mass power spectrum, as it is unaffected by…

天体物理学 · 物理学 2011-05-05 David Bacon , Alexandre Refregier , Richard Ellis

We discuss observations of the linearly polarized component of the diffuse galactic radio background. These observations, with an angular resolution of 4', were made with the Westerbork Synthesis Radio Telescope (WSRT) in 5 frequency bands…

天体物理学 · 物理学 2007-05-23 M. Haverkorn , P. Katgert , A. G. de Bruyn

We compute the two-point angular correlation function $w(\theta)$ for a sample of $\sim$ 1700 galaxies to a magnitude-limit equivalent to $R \sim 29.5$ using a catalog derived from the Hubble Deep Field images. A non zero value of…

天体物理学 · 物理学 2009-10-28 Jens V. Villumsen , Wolfram Freudling , Luiz N. da Costa

We present high sensitivity and absolutely calibrated images of diffuse radio polarisation at a resolution of about 10 arcmin covering the range 10 degr <l<34 degr and |b|<5 degr at 2.3 GHz from the S-band Parkes All Sky Survey and at 4.8…

星系天体物理 · 物理学 2015-06-17 X. H. Sun , B. M. Gaensler , E. Carretti , C. R. Purcell , L. Stavelley-Smith , G. Bernardi , M. Haverkorn

Gravitational-wave (GW) observations by a network of ground-based laser interferometric detectors allow us to probe the nature of GW polarizations. This would be an interesting test of general relativity (GR), since GR predicts only two…

广义相对论与量子宇宙学 · 物理学 2021-01-27 Srashti Goyal , K. Haris , Ajit Kumar Mehta , Parameswaran Ajith

Gravitational lensing can amplify the apparent brightness of distant sources. Images that are highly magnified are often part of multiply-imaged systems, but we consider the possibility of having large magnifications without additional…

天体物理学 · 物理学 2009-11-10 Charles R. Keeton , Michael Kuhlen , Zoltan Haiman

We analyze the first-year MACHO collaboration observations of microlensing towards the Galactic center using a new direct likelihood technique that is sensitive to the distribution of the events on the sky. We consider the full set of 41…

天体物理学 · 物理学 2007-05-23 Geza Gyuk

In the last decade the detection of individual massive dark matter sub-halos has been possible using potential correction formalism in strong gravitational lens imaging. Here we propose a statistical formalism to relate strong gravitational…

宇宙学与河外天体物理 · 物理学 2017-10-17 Saikat Chatterjee , Léon V. E. Koopmans

We present estimates of line-of-sight distortion fields derived from the 95 GHz and 150 GHz data taken by BICEP2, BICEP3, and Keck Array up to the 2018 observing season, leading to cosmological constraints and a study of instrumental and…

The total and polarized radio continuum emission of 20 barred galaxies was observed with the Very Large Array (VLA) at 3, 6, 18 and 22 cm and with the Australia Telescope Compact Array (ATCA) at 6 cm and 13 cm. Maps at 30 arcsec angular…

天体物理学 · 物理学 2009-11-07 R. Beck , V. Shoutenkov , M. Ehle , J . I. Harnett , R. F. Haynes , A. Shukurov , D. D. Sokoloff , M. Thierbach

We have identified seven (field) elliptical galaxies acting as strong gravitational lenses and have used them to measure cosmological parameters. To find the most likely value for Omega_m (= Omega_matter) and Lambda, we have used the…

天体物理学 · 物理学 2009-10-28 Myungshin Im , Richard E. Griffiths , Kavan U. Ratnatunga

We describe the effects of weak gravitational lensing by cosmological large scale structure on the diffuse emission of 21 centimeter radiation from neutral hydrogen at high redshifts during the era of reionization. The ability to observe…

天体物理学 · 物理学 2010-11-11 Kaisey S. Mandel , Matias Zaldarriaga

We present deep VLA observations of the polarization of radio sources in the GOODS-N field at 1.4 GHz at resolutions of 1.6" and 10". At 1.6", we find that the peak flux cumulative number count distribution is N($>$p) $\sim$ 45 *…

星系天体物理 · 物理学 2014-03-31 Lawrence Rudnick , Frazer Owen