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Related papers: Short timescale variability in the Faint Sky Varia…

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We present an analysis of the color and variability characteristics for point sources in the Faint Sky Variability Survey (FSVS). The FSVS cataloged ~23 square degrees in BVI filters from ~16--24 mag to investigate variability in faint…

Astrophysics · Physics 2008-11-26 M. E. Huber , M. E. Everett , S. B. Howell

The mJy variable extragalactic radio sky is known to be broadly non-changing with approximately $3\%$ of persistent radio sources exhibiting variability which is largely AGN-related. In the faint (<mJy) flux density regime, it is widely…

The potential of the Sloan Digital Sky Survey for wide-field variability studies is illustrated using multi-epoch observations for 3,000,000 point sources observed in 700 deg2 of sky, with time spans ranging from 3 hours to 3 years. These…

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

We discuss the first results from the Faint Sky Variability Survey (Groot et al. 2000). The data consist of V-band light curves, BVI colours, astrometry, and morphology information on several hundred thousand point and extended sources in…

Astrophysics · Physics 2009-09-25 M. E. Everett , M. E. Huber , S. B. Howell

We have shown previously that a broad correlation between the peak radio luminosity and the variability time-scales, approximately L ~ t^5, exists for variable synchrotron emitting sources and that different classes of astrophysical source…

High Energy Astrophysical Phenomena · Physics 2017-08-30 M. Pietka , T. D. Staley , M. L. Pretorius , R. P. Fender

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 results of X-ray spectral and time-domain variability analyses of 4 faint, "quiescent" blazars from the Swift-BAT 105-month catalog. We use observations from a recent, 5-month long NICER campaign, as well as archival BAT data.…

High Energy Astrophysical Phenomena · Physics 2023-02-01 Sergio A. Mundo , Richard Mushotzky

Fifteen ROSAT PSPC observations available in the public archive are analyzed in order to study time and spectral variability of the 12 EMSS AGN detected by ROSAT with more than 2000 net counts. Time variability was investigated on 13…

Astrophysics · Physics 2007-05-23 Paolo Ciliegi , Tommaso Maccacaro

A sample of 123 radio sources that exhibit significant variations at 1.4 GHz on a seven year base-line has been created using FIRST VLA B-array data from 1995 and 2002 on a strip at dec=0 near the south Galactic cap. This sample spans the…

Astrophysics · Physics 2009-11-10 W. H. de Vries , R. H. Becker , R. L. White , D. J. Helfand

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 have observed BL Lacertae in the B, R and I bands for 2 nights in July, 1999, and 3 nights in July, 2001. The observations resulted in almost evenly sampled light curves, with an average sampling interval of ~5 min. The source is…

Astrophysics · Physics 2009-11-07 I. E. Papadakis , P. Boumis , V. Samaritakis , J. Papamastorakis

We search for variable sources, using the data of the surveys conducted on the RATAN-600 radio telescope in 1980-1994 at 3.94 GHz. To test the radio sources of the RCR (RATAN Cold Refined) catalog for variability, we estimated the long-term…

Astrophysics of Galaxies · Physics 2014-09-15 E. K. Majorova , O. P. Zelenkova

We present results from a radio survey for variable and transient sources on 15-min timescales, using the Australian SKA Pathfinder (ASKAP) pilot surveys. The pilot surveys consist of 505 h of observations conducted at around 1 GHz…

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

We augment the two widest/deepest 1.4 GHz radio surveys: the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), with the mean epoch in which each source was observed. We use these catalogs to…

Astrophysics of Galaxies · Physics 2015-05-28 Eran O. Ofek , Dale A. Frail

We search a sample of 5,685,060 isolated sources in the All Sky Automated Survey for SuperNovae (ASAS-SN) with 14.5<g<15 mag for slowly varying sources with brightness changes larger than ~0.03 mag/year over 10 years. We find 426…

Solar and Stellar Astrophysics · Physics 2025-11-06 Sydney Petz , C. S. Kochanek , K. Z. Stanek , Benjamin J. Shappee , Subo Dong , J. L. Prieto , Todd A. Thompson

We monitored the BL Lac object S5 0716+714 in the optical band during October 2008, December 2008 and February 2009 with a best temporal resolution of about 5 minutes in the BVRI bands. Four fast flares were observed with amplitudes ranging…

Astrophysics of Galaxies · Physics 2014-11-20 H. Poon , J. H. Fan , J. N. Fu

We report on the variability of 443 flat spectrum, compact radio sources monitored using the VLA for 3 days in 4 epochs at ~ 4 month intervals at 5 GHz as part of the Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey. Over…

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