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Crimea, Ukraine

Aguirre J.E.,University of Pennsylvania | Parsons A.R.,University of California at Berkeley | Bradley R.F.,U.S. National Radio Astronomy Observatory | Carilli C.L.,U.S. National Radio Astronomy Observatory | And 7 more authors.
2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014 | Year: 2014

The Precision Array for Probing the Epoch of Reionization (PAPER) is a focused experiment aimed at detecting the spatial power spectrum of neutral hydrogen emission during the Epoch of Reionization (EoR). PAPER is an interferometer operating from 100 - 200 MHz at the site of the future Square Kilometre Array (SKA) site in South Africa. The PAPER antennas measure linear polarization and the correlator produces full-Stokes output. PAPER currently has 64 antennas and has just completed a 141-day science integration. An expansion to 128 antennas and another long observing campaign will be complete in late 2013. © 2014 IEEE. Source


Moore D.F.,University of Pennsylvania | Aguirre J.E.,University of Pennsylvania | Parsons A.R.,University of California at Berkeley | Bradley R.F.,U.S. National Radio Astronomy Observatory | And 7 more authors.
2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014 | Year: 2014

Polarized foregrounds pose a threat for attempts to measure the 21cm Epoch of Reionization (EoR) power spectrum. Faraday rotation of natively polarized synchrotron emission modulates the phase of the polarization states Q and U by a factor of exp{-2iRMλ2}, where λ is the wavelength of incident light, and RM is a function of the magnetic field and electron density along the line of sight. This phase-factor is non-orthogonal to the frequency sine waves composing the EoR power spectrum, creating a potential leakage from polarized emission into the power spectrum. My recent paper, Moore, et al. 2013, exposes this as a problem, and presents a simulation estimating its severity. © 2014 IEEE. Source


Aguirre J.E.,University of Pennsylvania | Parsons A.R.,University of California at Berkeley | Bradley R.F.,U.S. National Radio Astronomy Observatory | Carilli C.L.,U.S. National Radio Astronomy Observatory | And 7 more authors.
2014 United States National Committee of URSI National Radio Science Meeting, USNC-URSI NRSM 2014 | Year: 2014

The Precision Array for Probing the Epoch of Reionization (PAPER) is a focused experiment aimed at detecting the spatial power spectrum of neutral hydrogen emission during the Epoch of Reionization (EoR). PAPER is an interferometer operating from 100 - 200 MHz, with antennas measuring linear polarization and a correlator producing full-Stokes output. The science array is located at the site of the future Square Kilometre Array (SKA) site in South Africa, with a prototyping and test facility in Green Bank, WV. A staged build-out of PAPER South Africa (PSA) began in late 2009. PAPER has been obtaining science-grade observations since late 2011, when 32 dipoles (PSA-32) began taking data full-Stokes data. PAPER currently has 64 antennas and has just completed a 141-day science integration (PSA-64). An expansion to 128 antennas and another long observing campaign will be complete in late 2013. © 2014 IEEE. Source


Volkov I.M.,Moscow State University | Volkova N.S.,Moscow State University | Nikolenko I.V.,Radio Astronomy Laboratory | Chochol D.,Slovak Academy of Sciences
Astronomy Reports | Year: 2011

We present the first estimates of the relative and absolute parameters of the eclipsing binary EQ Boo based on a light-curve analysis (P = 5.43 d, V = 8.8 m). This star is simultaneously Component A of the visual binary ADS 9422 (spectral types F7V + G0V; separation of the components 1.3″; magnitude difference 0.7 m). The derived disagreement between the components' physical parameters and the assumption that they have the same age can be removed if there is a fourth, late-type star in the system. This is also able to explain the observed anomaly in the behavior of the O-C residuals at times of minima. © 2011 Pleiades Publishing, Ltd. Source


Vol'vach A.E.,Radio Astronomy Laboratory | Vol'vach L.N.,Radio Astronomy Laboratory | Kut'kin A.M.,RAS Lebedev Physical Institute | Larionov M.G.,RAS Lebedev Physical Institute | And 2 more authors.
Astronomy Reports | Year: 2010

Long-term, multi-frequency monitoring of the radio fluxes of the four BL Lac objects 3C 120, OJ 287, 1308+326, and BL Lac is considered. Harmonic components of the flux variability on scales from one year to decades are determined. The observational data used were obtained at the Radio Astronomy Laboratory of the Crimean Astrophysical Observatory (Ukraine) and the University of Michigan Radio Astronomy Observatory (USA). These data are used to construct kinematic models for active galactic nuclei using values for the orbital and precessional periods of binary systems consisting of supermassive black holes. The derived speeds of the companions in their orbits lie in the narrow range 3000-4000 km/s. The orbital radii for the binary supermassive black holes also lie in a narrow range, 1017-1018 cm, providing evidence that observed prominent examples of active galactic nuclei are fairly close binary systems. The parameters of the mediumin which the components of the binary systems are moving are estimated, as well as the rates at which the systems are losing orbital angular momentum and their lifetimes to coalescence. © Pleiades Publishing, Ltd., 2010. Source

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