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

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We present results of monitoring observations of the micro-quasars CygnusX-1 and Cygnus X-3 at 0.61 and 1.28 GHz. The observations were performed with Giant Meter-wave Radio Telescope, GMRT, between 2003 June and 2005 January. Variable,…

Spectral variability of radio sources encodes information about the conditions of intervening media, source structure, and emission processes. With new low-frequency radio interferometers observing over wide fractional bandwidths, studies…

Astrophysics of Galaxies · Physics 2020-12-23 K. Ross , J. R. Callingham , N. Hurley-Walker , N. Seymour , P. Hancock , T. M. O. Franzen , J. Morgan , S. V. White , M. E. Bell , P. Patil

Studying the interplay between massive star formation and the interstellar medium (ISM) is paramount to understand the evolution of galaxies. Radio continuum (RC) emission serves as an extinction-free tracer of both massive star formation…

Variability in the brightness of Young Stellar Objects (YSOs) is a common phenomenon that can be caused by changes in various factors, including accretion, extinction, disk morphology, interactions between the disk and the stellar…

Solar and Stellar Astrophysics · Physics 2023-12-12 Sieun Lee , Jeong-Eun Lee , Carlos Contreras Peña , Doug Johnstone , Gregory Herczeg , Seonjae Lee

This paper presents the results of the 2009-2010 monitoring sessions of the starburst galaxy M82, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN) at 5GHz and e-MERLIN at 6GHz. Combining several 5GHz MERLIN…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 M. A. Gendre , D. M. Fenech , R. J. Beswick , T. W. B. Muxlow , M. K. Argo

We have used the University of Tasmania's 30 m radio telescope at Ceduna in South Australia to regularly monitor the flux density of a number of southern blazars. We report the detection of an annual cycle in the variability timescale of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Steven J. B. Carter , Simon P. Ellingsen , Jean-Pierre Macquart , James E. J. Lovell

A long (155 hours) ASCA observation was performed of two ultra luminous compact X-ray sources, Source 1 and Source 2, in the spiral galaxy IC 342. While Source 1 that was in a hard spectral state varied little, Source 2 that was in its soft…

Astrophysics · Physics 2009-11-07 M. Sugiho , J. Kotoku , K. Makishima , A. Kubota , T. Mizuno , Y. Fukazawa , M. Tashiro

For more than a decade from the late 1980s to the late 1990s, the intraday variable (IDV) quasar 0917+624 was known to be strongly variable with amplitude variations of 10-20% within 0.8 to 1.6 days. During that period it showed faster…

Astrophysics · Physics 2011-11-09 S. Bernhart , T. P. Krichbaum , L. Fuhrmann , A. Kraus

Combining measurements taken using the Wilkinson Microwave Anisotropy Probe (WMAP) from 2001 to 2008 with measurements taken using Planck from 2009 to 2010, we investigate the long-term flux density variability of extragalactic radio…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 X. Chen , J. P. Rachen , M. Lopez-Caniego , C. Dickinson , T. J. Pearson , L. Fuhrmann , T. P. Krichbaum , B. Partridge

Variability of a galaxy's core radio source can be a significant consequence of AGN accretion. However, this variability has not been well studied, particularly at high radio frequencies. As such, we report on a campaign monitoring the high…

We present Very Large Array (VLA) 8.5-GHz light curves of the two lens images of the Cosmic Lens All Sky Survey (CLASS) gravitational lens B1600+434. We find a nearly linear decrease of 18-19% in the flux densities of both lens images over…

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

We report results based on the monitoring of the BL Lac object Mrk 501 in the optical (B, V and R) passbands from March to May 2000. Observations spread over 12 nights were carried out using 1.2 meter Mount Abu Telescope, India and 61 cm…

Astrophysics · Physics 2009-06-23 A. C. Gupta , W. G. Deng , U. C. Joshi , J. M. Bai , M. G. Lee

The VLA-COSMOS Large Project has imaged the 2 sq.deg. COSMOS field with a resolution of 1.5 arcsec and a sensitivity of about 11 microJy (1 sigma) yielding to a catalog of about 3600 radio sources. In this paper we present a further…

Astrophysics · Physics 2009-11-13 M. Bondi , P. Ciliegi , E. Schinnerer , V. Smolcic , K. Jahnke , C. Carilli , G. Zamorani

We present a study of the radio variability of bright, $S_{1.4}\geq100$ mJy, high-redshift quasars at $z\geq3$ on timescales up to 30-40 years. The study involved simultaneous RATAN-600 measurements at frequencies of 2.3, 4.7, 8.2, 11.2,…

We present the results of a 3.3-year project to monitor the flux density of Sagittarius A* at 2.0, 1.3, and 0.7 cm with the VLA. The fully calibrated light curves for Sgr A* at all three wavelengths are presented. Typical errors in the flux…

Astrophysics · Physics 2009-11-10 R. M. Herrnstein , J. -H. Zhao , G. C. Bower , W. M. Goss

In order to extend our previous studies of the unexplained phenomenon of cyclic amplitude variations in pulsating red giants, we have used the AAVSO time-series analysis package VSTAR to analyze long-term AAVSO visual observations of 50…

Solar and Stellar Astrophysics · Physics 2017-09-29 John R. Percy , Jennifer Laing

We carried out a pilot campaign of radio and optical band intra-day variability (IDV) observations of five blazars (3C66A, S5 0716+714, OJ287, B0925+504, and BL Lacertae) on December 18--21, 2015 by using the radio telescope in Effelsberg…

We present here the results from an extensive scintillation study of twenty pulsars in the dispersion measure (DM) range 3 - 35 pc cm^-3 caried out using the Ooty Radio Telescope (ORT) at 327 MHz, to investigate the distribution of ionized…

Astrophysics · Physics 2009-10-30 N. D. Ramesh Bhat , Yashwant Gupta , A. Pramesh Rao

Multi-wavelength VLA observations of two extended radio galaxies, 0235-197 and 1203+043 are presented. There is some evidence from earlier studies that these two sources exhibit low frequency (<1 GHz) variability. This work shows that both…

Astrophysics · Physics 2009-10-31 W. Junor , F. Mantovani , R. Morganti , L. Padrielli

Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying…

Solar and Stellar Astrophysics · Physics 2015-06-04 Á. Kóspál , P. Ábrahám , J. A. Acosta-Pulido , C. P. Dullemond , Th. Henning , M. Kun , Ch. Leinert , A. Moór , N. J. Turner
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