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Related papers: The Micro-Arcsecond Scintillation-Induced Variabil…

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We present the first unambiguous case of external variability of a radio gravitational lens, CLASS B1600+434. The VLA 8.5-GHz difference light curve of the lensed images, taking the proper time-delay into account, shows the presence of…

Astrophysics · Physics 2007-05-23 L. V. E. Koopmans , A. G. de Bruyn

According to a generally accepted paradigm, small intrinsic sizes of Compact Steep Spectrum (CSS) radio sources are a direct consequence of their youth, but in later stages of their evolution they are believed to become large-scale sources.…

Astrophysics · Physics 2009-11-13 Andrzej Marecki , Magdalena Kunert-Bajraszewska , Ralph E. Spencer

We present observations of high-amplitude rapid (2 s) variability toward two bright, compact extragalactic radio sources out of several hundred of the brightest radio sources in one of the 30x30 deg MWA Epoch of Reionization fields using…

The NSF's Karl G. Jansky Very Large Array (VLA) is used to observe 122 magnetic cataclysmic variables (MCVs) during three observing semesters (13B, 15A, and 18A). We report radio detections of 33 stars with fluxes in the range 6--8031 uJy.…

Solar and Stellar Astrophysics · Physics 2020-06-16 Paul Barrett , Christopher Dieck , Anthony J. Beasley , Paul A Mason , Kulinder P. Singh

The evidence for refractive interstellar scintillation (RISS) being the main cause for rapid intraday variations (Intraday Variability, IDV) in Quasars and BL Lacs has recently become stronger. If IDV is still a complex composition of…

Astrophysics · Physics 2007-05-23 L. Fuhrmann , G. Cimò , T. P. Krichbaum , T. Beckert , A. Kraus , A. Witzel , J. A. Zensus

We report on I band photometric observations of 21 stars with spectral types between M8 and L4 made using the Isaac Newton Telescope. The total amount of time for observations which had a cadence of <2.3 mins was 58.5 hrs, with additional…

Solar and Stellar Astrophysics · Physics 2015-09-09 Gavin Ramsay , Pasi Hakala , J Gerry Doyle

Interplanetary scintillation observations of 48 of the 55 Augusto et al. (1998) flat spectrum radio sources were carried out at 111 MHz using the interplanetary scintillation method on the Large Phased Array (LPA) in Russia. Due to the…

Astrophysics · Physics 2009-11-11 S. A. Tyul'bashev , A. Pedro

VLA 1.4 GHz (rms noise ~0.012 mJy) and MIPS 24 and 70 micron (rms noise ~0.02 and ~1.7 mJy, respectively) observations covering the 2 square degree COSMOS field are combined with an extensive multi-wavelength data set to study the evolution…

Results of two years of continuous monitoring of flux density variations at 8.3 and 2.3 GHz of the Galactic Center super-massive black hole candidate Sgr A* are reported. The average RMS modulation indices are 6% and 2.5% at 8.3 & 2.3 GHz…

Astrophysics · Physics 2007-05-23 Heino Falcke

Aims - We report new Very Large Array polarimetric observations of Compact Steep-Spectrum (CSS) sources at 8.4, 15, and 23GHz. Methods - Using multi-frequency VLA observations we have derived sub-arcsecond resolution images of the total…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 F. Mantovani , A. Rossetti , W. Junor , D. J. Saikia , C. J. Salter

We present an analysis of interplanetary scintillation (IPS) observations conducted with the Arecibo 305-m radio telescope during the minimum phase at the end of solar cycle 24 and the onset of solar cycle 25. These observations span a…

Solar and Stellar Astrophysics · Physics 2025-02-25 P. K. Manoharan , C. J. Salter

We present the V band variability analysis of the point sources in the Faint Sky Variability Survey on time scales from 24 minutes to tens of days. We find that about one percent of the point sources down to V = 24 are variables. We discuss…

We report on slow phase variations of the response of the space-ground radio interferometer RadioAstron during observations of pulsar B0329+54. The phase variations are due to the ionosphere and clearly distinguishable from effects of…

Astrophysics of Galaxies · Physics 2021-07-14 M. V. Popov , N. Bartel , M. S. Burgin , T. V. Smirnova , V. A. Soglasnov

We report a serendipitous detection of rapid, large amplitude flux density variations in the highly core-dominated, flat-spectrum radio quasar 1156+295 during an observing session at the Very Long Baseline Array (VLBA). The source was…

Astrophysics · Physics 2008-10-06 T. Savolainen , Y. Y. Kovalev

The compact radio source Sgr\,A*, associated with the super massive black hole at the center of the Galaxy, has been studied with VLBA observations at 3 frequencies (22, 43, 86\,GHz) performed on 10 consecutive days in May 2007. The total…

Astrophysics of Galaxies · Physics 2015-05-20 R. -S. Lu , T. P. Krichbaum , A. Eckart , S. König , D. ~Kunneriath , G. Witzel , A. Witzel , J. A. Zensus

We present radio observations of 19 candidate compact steep-spectrum (CSS) objects selected from a well-defined, complete sample of 52 B2 radio sources of intermediate strength. These observations were made with the VLA A-array at 4.835…

Astrophysics · Physics 2009-11-07 D. J. Saikia , P. Thomasson , R. E. Spencer , F. Mantovani , C. J. Salter , S. Jeyakumar

Short time-scale radio variations of compact extragalactic radio quasars and blazars known as IntraDay Variability (IDV) can be explained in at least some sources as a propagation effect; the variations are interpreted as scintillation of…

We present Very Large Array (VLA) observations at 1.4 GHz and 5 GHz of a sample of 12 Quasi-stellar Objects (QSOs) at z = 3.99 to 4.46. The sources were selected as the brightest sources at 250 GHz from the recent survey of Omont et al.…

Astrophysics · Physics 2009-11-06 C. L. Carilli , F. Bertoldi , A. Omont , P. Cox , R. G. McMahon , K. G. Isaak

The Rapid Temporal Survey (RATS) explores the faint, variable sky. Our observations search a parameter space which, until now, has never been exploited from the ground. Our strategy involves observing the sky close to the Galactic plane…

Astrophysics of Galaxies · Physics 2015-05-27 Thomas Barclay , Gavin Ramsay , Pasi Hakala , Ralf Napiwotzki , Gijs Nelemans , Stephen Potter , Ian Todd

We present light curves for 149 sources monitored with the Green Bank Interferometer. The light curves are at two radio frequencies (approximately 2.5 and 8.2 GHz) and range from 3 to 15 yrs in length, covering the interval 1979--1996, and…