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We present the analysis results of flux and spectral variability of the blazar OP 313 across intra-night to short-term timescales using BVRI photometric data, gathered over 25 nights from Nov 2024 to May 2025, using two optical telescopes…

High Energy Astrophysical Phenomena · Physics 2025-09-11 P. U. Devanand , Alok C. Gupta , Karan Dogra , Shubham Kishore , Tushar Tripathi

Keane et al. (2016) have recently reported the discovery of a new fast radio burst, FRB150418, with a promising radio counterpart at 5.5 and 7.5 GHz -- a rapidly decaying source, falling from 200-300 $\mu$Jy to 100 $\mu$Jy on timescales of…

High Energy Astrophysical Phenomena · Physics 2016-06-08 Kazunori Akiyama , Michael D. Johnson

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

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

The transient black hole binary XTE J1118+480 exhibited dramatic rapid variability at all wavelengths which were suitably observed during its 2000 April-July outburst. We examine time-resolved X-ray, ultraviolet, optical, and infrared data…

We report the discovery of a double-double radio source (DDRS) J0028+0035. We observed it with LOFAR, GMRT, and the VLA. By combining our observational data with those from the literature, we gathered an appreciable set of radio flux…

Astrophysics of Galaxies · Physics 2020-12-29 A. Marecki , M. Jamrozy , J. Machalski , U. Pajdosz-Smierciak

We have identified the 1.4 GHz radio source FIRST J102347.6+003841 (hereafter FIRST J1023+0038) with a previously unknown 17th-mag Galactic cataclysmic variable (CV). The optical spectrum resembles that of a magnetic (AM Herculis- or DQ…

Astrophysics · Physics 2009-11-07 Howard E. Bond , Richard L. White , Robert H. Becker , M. Sean O'Brien

The turbulent nature of the ionised interstellar medium (IISM) causes dispersion measure (DM) and scattering variations in pulsar timing measurements. To improve precision of gravitational wave measurements, pulsar timing array (PTA)…

High Energy Astrophysical Phenomena · Physics 2025-11-06 A. D. Kulkarni , R. M. Shannon , D. J. Reardon , M. T. Miles

We present photometric observations of the BL Lacertae object S5 0716+714 with a temporal resolution of 120 s in the Sloan i' and r' bands. These observations were conducted using the Comet Search Program telescope at Xingming Observatory…

Astrophysics of Galaxies · Physics 2025-03-17 Huai-Zhen Li , Di-Fu Guo , Long-Hua Qin , Fen Liu , Hong-Tao Liu , Ting-Feng Yi , Quan-Gui Gao , Shi-Feng Huang , Xing Gao , Xu Chen

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

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…

9C J1503+4528 is a very young CSS radio galaxy, with an age of order 10^4 years. This source is an ideal laboratory for the study of the intrinsic host galaxy/IGM properties, radio source interactions, evidence for young stellar populations…

Astrophysics · Physics 2009-11-11 K. J. Inskip , D. Lee , Garret Cotter , A. C. S. Readhead , T. J. Pearson

In radio bands, the study of compact radio sources can be affected by propagation effects through the Interstellar Medium. These are usually attributed to the presence of turbulent intervening plasma along the line of sight. Here, two of…

Astrophysics · Physics 2013-09-26 K. É. Gabányi , S. Britzen , T. P. Krichbaum , U. Bach , L. Fuhrmann , A. Kraus , A. Witzel , J. A. Zensus

In this paper, we used the database of the university of Michigan Radio Astronomy Observatory (UMRAO) at three (4.8 GHz, 8.0 GHZ, and 14.5 GHz) radio frequency to analyze the radio light curves by the power spectral analysis method in…

Astrophysics · Physics 2009-11-13 J. H. Fan , Y. Liu , Y. H. Yuan

Using data from the Large European Array for Pulsars (LEAP), and the Effelsberg telescope, we study the scintillation parameters of the millisecond pulsar J0613-0200 over a 7 year timespan. The "secondary spectrum" -- the 2D power spectrum…

With an aim to explore optical variability at diverse timescales in BL Lac source S5 0716+714, it was observed for 46 nights during 2013 January 14 to 2015 June 01 when it underwent two major outbursts. The observations were made using the…

Astrophysics of Galaxies · Physics 2018-09-26 Navpreet Kaur , Kiran S. Baliyan , S. Chandra , Sameer , S. Ganesh

We report the discovery of J1218+1813, a circular diffuse radio source detected in the Very Large Array (VLA) FIRST survey at 1400 MHz. The source has an angular diameter of approximately one arcminute, corresponding to a physical size of…

Astrophysics of Galaxies · Physics 2025-06-24 Shobha Kumari , Sabyasachi Pal , Souvik Manik

We associate the existence of short-lived compact radio sources with the intermittent activity of the central engine caused by a radiation pressure instability within an accretion disk. Such objects may constitute a numerous sub-class of…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-11 Bozena Czerny , Aneta Siemiginowska , Agnieszka Janiuk , Blazej Nikiel-Wroczynski , Lukasz Stawarz

Scintillation of compact radio sources results from the interference between images caused by multipath propagation, and probes the intervening scattering plasma and the velocities of the emitting source and scattering screen. In…

High Energy Astrophysical Phenomena · Physics 2021-11-23 R. A. Main , G. H. Hilmarsson , V. R. Marthi , L. G. Spitler , R. S. Wharton , S. Bethapudi , D. Z. Li , H. -H. Lin

The recent detection of the quasi-stellar object (QSO) VIKING J231818.3$-$311346 (hereafter VIK J2318$-$3113) at redshift $z=6.44$ in the Rapid ASKAP Continuum Survey (RACS) uncovered its radio-loud nature, making it one of the most distant…