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Many of the compact extragalactic radio sources that are used as fiducial points to define the celestial reference frame are known to have proper motions detectable with long-term geodetic/astrometric Very Long Baseline Interferometry…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 A. Moór , S. Frey , S. B. Lambert , O. Titov , J. Bakos

We present sub-arcsecond resolution multi-frequency (8 and 22 GHz) VLA images of five low power compact (LPC) radio sources, and phase referenced VLBA images at 1.6 GHz of their nuclear regions. At the VLA resolution we resolve the…

Astrophysics · Physics 2009-11-11 M. Giroletti , G. Giovannini , G. B. Taylor

We present observational results for extragalactic radio sources with milliarcsecond components, obtained with the 600 meter ring radio telescope RATAN-600 from 1st to 22nd December, 1997. For each source, a six frequency broad band radio…

We report on centimeter VLA and VLBI observations of the giant, low power radio galaxy 1144+35. These observations are sensitive to structures on scales from less than 1 parsec to greater than 1 megaparsec. Diffuse steep spectrum lobes on…

Astrophysics · Physics 2009-10-31 G. Giovannini , G. B. Taylor , E. Arbizzani , M. Bondi , W. D. Cotton , L. Feretti , L. Lara , T. Venturi

We present an XMM-Newton observation of the radio galaxy 4C 23.56 at z=2.48 which reveals extended X-ray emission coincident with the radio lobes spanning \~0.5 Mpc. These are the largest X-ray-bright lobes known at z>2. Under the…

Astrophysics · Physics 2008-11-26 O. Johnson , O. Almaini , P. N. Best , J. Dunlop

Planetary nebulae expand on time scales of 10^3-10^4 yr. For nearby objects, their expansion can be detected within years to decades. The pattern of expansion probes the internal velocity field and provides clues to the nebula ejection…

Astrophysics of Galaxies · Physics 2015-05-28 C. Szyszka , A. A. Zijlstra , J. R. Walsh

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from…

Astrophysics · Physics 2009-10-31 D. J. Saikia , S. Jeyakumar , C. J. Salter , P. Thomasson , R. E. Spencer , F. Mantovani

The high-frequency integrated spectra of Compact Steep Spectrum (CSS) sources show breaks with a moderate spectral steepening well fitted by continuous injection synchrotron spectra. In lobe-dominated CSS sources the radiative ages deduced…

Astrophysics · Physics 2009-10-31 M. Murgia , C. Fanti , R. Fanti , L. Gregorini , U. Klein , K. -H. Mack , M. Vigotti

(Abridged) METHODS: We performed SMA observations at 1.3 mm with both the most extended and compact array configurations, providing sub-arcsecond and high sensitivity maps of various molecular lines, including both hot-core and outflow…

Astrophysics of Galaxies · Physics 2015-06-18 A. Sanna , R. Cesaroni , L. Moscadelli , Q. Zhang , K. M. Menten , S. Molinari , A. Caratti o Garatti , J. M. De Buizer

We present the second catalogue of accurate positions and correlated flux densities for 1100 compact extragalactic radio sources that were not observed before 2008 at high angular resolution. The catalogue spans the declination range -90…

Instrumentation and Methods for Astrophysics · Physics 2019-04-15 Leonid Petrov , Alet de Witt , Elaine M. Sadler , Chris Phillips , Shinji Horiuchi

We present 8 epochs of 7 mm dual-polarization VLBA observations of the gravitational lens system PKS 1830-211 made over the course of 14 weeks. Clear changes in the relative positions of the cores of up to $80 \mu$arcseconds ($\mu$as) were…

Astrophysics · Physics 2007-05-23 Jin Chengjin , M. A. Garrett , S Nair , R. W. Porcas , A. R. Patnaik

The remarkably strong radio gravitational lens PKS 1830-211 consists of a one arcsecond diameter Einstein ring with two bright compact (milliarcsecond) components located on opposite sides of the ring. We have obtained 22 GHz VLBA data on…

We present multi-frequency VLBA observations of two polarized Compact Symmetric Objects (CSOs), J0000+4054 and J1826+1831, and a polarized CSO candidate, J1915+6548. Using the wavelength-squared dependence of Faraday rotation, we obtained…

Astrophysics · Physics 2011-02-11 N. E. Gugliucci , G. B. Taylor , A. B. Peck , M. Giroletti

The evolution of the radio emission from Sco X-1 is determined from a 56-hour continuous VLBI observation and from shorter observations over a four-year period. The radio source consists of a variable core near the binary, and two variable…

Astrophysics · Physics 2009-11-06 E. B. Fomalont , B. J. Geldzahler , C. F. Bradshaw

We present the observational results of the Gamma-ray blazar, 3C 66A, at 2.3, 8.4, and 22 GHz at 4 epochs during 2004-05 with the VLBA. The resulting images show an overall core-jet structure extending roughly to the south with two…

High Energy Astrophysical Phenomena · Physics 2015-01-13 Guang-Yao Zhao , Yong-Jun Chen , Zhi-Qiang Shen , Hiroshi Sudou , Satoru Iguchi

We present results of Very Long Baseline Array (VLBA) observations of PKS 0528+134 at five frequencies (2.3, 5.0, 8.4, 15.4, and 22.2 GHz). These quasi-simultaneous data enable us to study the spectral distribution of Very Long Baseline…

Astrophysics · Physics 2009-11-11 H. -B. Cai , Z. -Q. Shen , X. Chen , L. -L. Shang

Multifrequency observations with the GMRT and the VLA are used to determine the spectral breaks in consecutive strips along the lobes of a sample of selected giant radio sources (GRSs) in order to estimate their spectral ages. The maximum…

Astrophysics · Physics 2009-11-13 M. Jamrozy , C. Konar , J. Machalski , D. J. Saikia

In 2010/3, the Large Area Telescope on board Fermi revealed a transient gamma-ray source, positionally coincident with the optical nova in the symbiotic binary, V407Cyg. This event marked the first discovery of gamma-ray emission from a…

Solar and Stellar Astrophysics · Physics 2020-07-01 M. Giroletti , U. Munari , E. Körding , A. Mioduszewski , J. Sokoloski , C. C. Cheung , S. Corbel , F. Schinzel , K. Sokolovsky , T. J. O'Brien

We present results from a large 86GHz global VLBI survey of compact radio sources. The main goal of the survey is to increase by factors of 3--5 the total number of objects accessible for future 3-mm VLBI imaging. The survey observations…

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