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

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We use archival data from the Phoenix Deep Survey to investigate the variable radio source population above 1mJy/beam at 1.4GHz. Given the similarity of this survey to other such surveys we take the opportunity to investigate the…

Astrophysics of Galaxies · Physics 2016-08-03 Paul Hancock , Jason Drury , Martin Bell , Tara Murphy , Bryan Gaensler

In this work, we present the results of our multi-band microvariability study of the famous blazar BL Lac. We performed microvariablity observations of the source in the optical VRI bands for 4 nights in the year 2016. We studied the…

High Energy Astrophysical Phenomena · Physics 2017-11-27 Gopal Bhatta , James R. Webb

We present new JVLA multi-frequency measurements of a set of stars in transition from the post-AGB to the Planetary Nebula phase monitored in the radio range over several years. Clear variability is found for five sources. Their light…

Solar and Stellar Astrophysics · Physics 2017-05-03 L. Cerrigone , G. Umana , C. Trigilio , P. Leto , C. S. Buemi , A. Ingallinera

The results of a climatological study of ionospheric disturbances derived from observations of cosmic sources from the Very Large Array (VLA) Low-frequency Sky Survey (VLSS) are presented. We have used the ionospheric corrections applied to…

Space Physics · Physics 2015-06-11 J. F. Helmboldt , W. M. Lane , W. D. Cotton

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 have performed monitoring observations of the 3-mm flux density toward the Galactic Center compact radio source Sgr A* with the Australia Telescope Compact Array since 2005 October. Careful calibrations of both elevation-dependent and…

Astrophysics of Galaxies · Physics 2009-07-22 Juan Li , Zhi-Qiang Shen , Atsushi Miyazaki , Lei Huang , R. J. Sault , Makoto Miyoshi , Masato Tsuboi , Takahiro Tsutsumi

We have studied the implications of high sensitivity polarization measurements of objects from the WMAP point source catalogue made using the VLA at 8.4, 22 and 43 GHz. The fractional polarization of sources is almost independent of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 R. A. Battye , I. W. A. Browne , M. W. Peel , N. J. Jackson , C. Dickinson

I describe an observational program aimed at understanding the radio emission from distant, rapidly evolving galaxy populations. These observations were carried out at 1.4 and 8.5 GHz with the VLA centered on the Hubble Deep Field. Further…

Astrophysics · Physics 2009-10-31 E. A. Richards

High-amplitude variability in Young Stellar Objects (YSOs) is usually associated with episodic accretion events. It has not been observed so far in massive YSOs. Here, the high-amplitude variable star sample of ContrerasPe\~{n}a et…

Solar and Stellar Astrophysics · Physics 2016-12-14 M. S. N. Kumar , C. Contreras-Pena , P. W. Lucas , M. A. Thompson

Thanks to the VISTA Variables in the Via Lactea (VVV) ESO Public Survey it is now possible to explore a large number of objects in those regions. This paper addresses the variability analysis of all VVV point sources having more than 10…

Results of the long-term monitoring observations of the 6.7 GHz Class II methanol masers associated with the four high-mass star-forming regions by Hitachi 32-m radio telescope are presented. We detected periodic flux variability in…

Astrophysics of Galaxies · Physics 2024-02-28 Yoshihiro Tanabe , Yoshinori Yonekura

We present a catalogue of ALMA flux density measurements of 754 calibrators observed between August 2012 and September 2017, for a total of 16,263 observations in different bands and epochs. The flux densities were measured reprocessing the…

The Coronet Cluster in the nearby R CrA dark cloud offers the rare opportunity to study at least four "class I" protostellar sources as well as one candidate "class 0" source, a Herbig Ae star, and a candidate brown dwarf within a few…

Astrophysics · Physics 2009-11-11 Jan Forbrich , Thomas Preibisch , Karl M. Menten

We have observed S4 0954+658 in the BVRI bands in 2001, and in the BI bands in 2002. The observations resulted in almost evenly sampled light curves, 3-8 hours long, with an average sampling interval of ~5-15 min. Because of the dense…

Astrophysics · Physics 2009-11-10 I. E. Papadakis , V. Samaritakis , P. Boumis , J. Papamastorakis

Context. Interstellar scintillation (ISS) of pulsar emission can be used both as a probe of the ionised interstellar medium (IISM) and cause corruptions in pulsar timing experiments. Of particular interest are so-called scintillation arcs…

We aim to search for evidence of annual modulation in the time scales of the BL Lac object S5 0716+714. The intra-day variability (IDV) observations were carried out monthly from 2005 to 2009, with the Urumqi 25m radio telescope at 4.8 GHz.…

High Energy Astrophysical Phenomena · Physics 2012-07-12 X. Liu , H. -G. Song , N. Marchili , B. -R. Liu , J. Liu , T. P. Krichbaum , L. Fuhrmann , J. A. Zensus

Analysis of rapid variability at 4.85 GHz for the BL BLac object 0925+504 is presented and discussed. The structure functions (SF) are investigated with both refractive and weak interstellar scintillation (RISS/WISS) models analytically.…

Astrophysics of Galaxies · Physics 2018-04-26 Jun Liu , Xiang Liu

We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength…

Cosmological applications of the "redshift - angular size" test require knowledge of the linear size of the "standard rod" used. In this paper, we study the properties of a large sample of 140 milliarcsecond compact radio sources with flux…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-28 Shuo Cao , Marek Biesiada , Xiaogang Zheng , Zong-Hong Zhu

We report on a blind survey for extragalactic radio variability that was carried out by comparing two epochs of data from the FIRST survey with a third epoch from a new 1.4 GHz survey of SDSS Stripe 82. The three epochs are spaced seven…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Jacqueline A. Hodge , Robert H. Becker , Richard L. White , Gordon T. Richards