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Related papers: First Results from MASIV: The Micro-Arcsecond Scin…

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We present variability analysis of data from the Northern Sky Variability Survey (NSVS). Using the clustering method which defines variable candidates as outliers from large clusters, we cluster 16,189,040 light curves, having data points…

Solar and Stellar Astrophysics · Physics 2012-02-13 Min-Su Shin , Hahn Yi , Dae-Won Kim , Seo-Won Chang , Yong-Ik Byun

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…

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

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

The Variables and Slow Transients (VAST) Survey on the Australian SKA Pathfinder (ASKAP) is designed to systematically explore the dynamic radio sky, detecting sources that vary on timescales from minutes to several years. In this paper, we…

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

VISTA Variables in the Via Lactea (VVV) is an ESO public near-infrared variability survey of the Galactic bulge and an adjacent area of the southern mid-plane. It will produce a deep atlas in the ZYJHKs filters, and a Ks-band time-series…

Solar and Stellar Astrophysics · Physics 2011-11-09 I. Dekany , M. Catelan , D. Minniti , the VVV Collaboration

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…

Context: The Red MSX Source (RMS) survey is a multi-wavelength campaign of follow-up observations of a colour-selected sample of candidate massive young stellar objects (MYSOs) in the galactic plane. This survey is returning the largest…

Astrophysics of Galaxies · Physics 2015-05-14 J. C. Mottram , M. G. Hoare , S. L. Lumsden , R. D. Oudmaijer , J. S. Urquhart , M. R. Meade , T. J. T. Moore , J. J. Stead

Planetary-mass objects and brown dwarfs at the transition ($\rm{T}_{eff}\sim1300$\,K) from relatively red L dwarfs to bluer mid-T dwarfs show enhanced spectrophotometric variability. Multi-epoch observations support atmospheric…

Earth and Planetary Astrophysics · Physics 2024-05-21 Michael K. Plummer , Ji Wang , Étienne Artigau , René Doyon , Genaro Suárez

We present follow-up observations of 97 point sources from the Wilkinson Microwave Anisotropy Probe (WMAP) 3-year data, contained within the New Extragalactic WMAP Point Source (NEWPS) catalogue between declinations of -4 and +60 degrees;…

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

We present some first results on the variability, polarization and general properties of radio sources selected in a blind survey at 20 GHz, the highest frequency at which a sensitive radio survey has been carried out over a large area of…

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 report multi-epoch GMRT HI observations of the z = 0.3127 damped absorber towards the quasar PKS 1127-145, which reveal variability in both the absorption profile and the flux of the background source, over a time-scale of a few days.…

Astrophysics · Physics 2009-11-06 Nissim Kanekar , Jayaram N Chengalur

The extreme, intra-hour and > 10% rms flux density scintillation observed in AGNs such as PKS 0405-385, J1819+3845 and PKS 1257-326 at cm wavelengths has been attributed to scattering in highly turbulent, nearby regions in the interstellar…

Astrophysics of Galaxies · Physics 2011-09-22 J. Y. Koay , H. E. Bignall , J. -P. Macquart , D. L. Jauncey , B. J. Rickett , J. E. J. Lovell

Numerous eruptive variable young stellar objects (YSOs), mostly Class I systems, were recently detected by the near-infrared Vista Variables in the Via Lactea (VVV) survey. We present an exploratory near-infrared spectroscopic variability…

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

We use Murchison Widefield Array observations of interplanetary scintillation (IPS) to determine the source counts of point ($<$0.3 arcsecond extent) sources and of all sources with some subarcsecond structure, at 162 MHz. We have developed…

Astrophysics of Galaxies · Physics 2018-07-11 R. Chhetri , R. D. Ekers , J. Morgan , J. -P. Macquart , T. M. O. Franzen

There is new evidence which identifies seasonal changes of the variability time scale in intraday variable sources with refractive interstellar scintillation effects. Such a RISS-model takes the annual change of the Earth velocity relative…

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