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相关论文: Polarimetric imaging with the GMRT

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Mechanical and electronic imperfections can result into polarization leakage in individual antennas of a radio interferometer. Such leakages manifest themselves as closure errors even in co-polar visibility measurements of unpolarized…

天体物理学 · 物理学 2009-11-06 Sanjay Bhatnagar , Rajaram Nityananda

Emission from blazar jets in the ultraviolet, optical, and infrared is polarized. If these low-energy photons were inverse-Compton scattered, the upscattered high-energy photons retain a fraction of the polarization. Current and future…

高能天体物理现象 · 物理学 2015-02-03 Nachiketa Chakraborty , Vasiliki Pavlidou , Brian Fields

Context: Observations of polarized emission are a significant source of information on the magnetic field that pervades the Interstellar Medium of the Galaxy. Despite the acknowledged importance of the magnetic field in interstellar…

We completed observations with the Effelsberg 100-m radio telescope to measure the polarised emission from a complete sample of Compact Steep-Spectrum sources. We observed the sources at four different frequencies. We complemented these…

宇宙学与河外天体物理 · 物理学 2015-05-13 F. Mantovani , K. -H. Mack , F. M. Montenegro-Montes , A. Rossetti , A. Kraus

We define a complete sample of thirty-three GHz-Peaked-Spectrum (GPS) radio sources based on their spectral properties. We present measurements of the radio spectra and polarization of the complete sample and a list of additional GPS…

天体物理学 · 物理学 2016-08-30 C. Stanghellini , C. P. O'Dea , D. Dallacasa , S. A. Baum , R. Fanti , C. Fanti

The polarization properties of radio sources at very low frequencies (<200 MHz) have not been widely measured, but the new generation of low-frequency radio telescopes, including the Low Frequency Array (LOFAR: a Square Kilometre Array Low…

A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement…

We present the results from the first large (>100 source) 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN). The I, Q, U, and V Stokes parameter observations were performed with the XPOL polarimeter at the IRAM 30m…

宇宙学与河外天体物理 · 物理学 2014-11-20 I. Agudo , C. Thum , H. Wiesemeyer , T. P. Krichbaum

We present the integrated polarization properties of the four compact radio sources 3C48, 3C138, 3C147 and 3C286, from 1 to 50 GHz, over a 30-year time frame spanning 1982 to 2012. These four sources are commonly used as flux density and…

天体物理仪器与方法 · 物理学 2015-06-15 R. A. Perley , B. J. Butler

A polarimetric model for the power delay spectrum for inroom communication is proposed. The proposed model describes the gradual depolarization of the signal with delay. The model is based on the theory of room electromagnetics,…

信号处理 · 电气工程与系统科学 2022-02-16 Troels Pedersen , Ramoni Adeogun

Radio relics are Mpc-size synchrotron sources located in the outskirts of some merging galaxy clusters. Binary-merging systems with favorable orientation may host two almost symmetric relics, named double radio relics. Double radio relics…

宇宙学与河外天体物理 · 物理学 2022-09-28 C. Stuardi , A. Bonafede , K. Rajpurohit , M. Brüggen , F. de Gasperin , D. Hoang , R. J. van Weeren , F. Vazza

In this paper we present an error analysis for polarimetric data obtained with dual-beam instruments. After recalling the basic concepts, we introduce the analytical expressions for the uncertainties of polarization degree and angle. These…

天体物理学 · 物理学 2009-11-11 Ferdinando Patat , Martino Romaniello

The findings of a nine orbit calibration plan carried out during HST Cycle 15, to fully determine the NICMOS camera 2 (2.0 micron) polarization calibration to high accuracy, are reported. Recently Ueta et al. and Batcheldor et al. have…

天体物理学 · 物理学 2009-11-13 D. Batcheldor , G. Schneider , D. C. Hines , G. D. Schmidt , D. J. Axon , A. Robinson , W. Sparks , C. Tadhunter

The B-Machine Telescope is the culmination of several years of development, construction, characterization and observation. The telescope is a departure from standard polarization chopping of correlation receivers to a half wave plate…

天体物理仪器与方法 · 物理学 2013-11-11 Brian D. Williams

We report results from a deep polarization imaging of the nearby radio galaxy 3C$\,$84 (NGC$\,$1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86$\,$GHz at an ultra-high angular resolution of $50\mu$as…

We present multi-frequency maps of a portion of the Galactic Plane centered on a declination of -60 degrees with resolutions ranging from 0.2 to 0.9 degrees. The maps are optimized to detect unresolved source emission and are…

We present a concept for an imaging gamma-ray polarimeter operating from ~50 MeV to ~1 GeV. Such an instrument would be valuable for the study of high-energy pulsars, active galactic nuclei, supernova remnants, and gamma-ray bursts. The…

天体物理学 · 物理学 2009-11-10 P. F. Bloser , S. D. Hunter , G. O. Depaola , F. Longo

We develop two algorithms, based on maximum likelihood (ML) inference, for estimating the parameters of polarized radio sources which emit at a single rotation measure (RM), e.g., pulsars. These algorithms incorporate the flux density…

天体物理仪器与方法 · 物理学 2017-10-25 D. H. F. M. Schnitzeler , K. J. Lee

We present the detection and characterization of fluctuations in linearly polarized emission from the atmosphere above the South Pole. These measurements make use of data from the SPT-3G receiver on the South Pole Telescope in three…

Radio polarimetry is a three-dimensional statistical problem. The three-dimensional aspect of the problem arises from the Stokes parameters Q, U, and V, which completely describe the polarization of electromagnetic radiation and…

星系天体物理 · 物理学 2015-05-20 M. M. McKinnon