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We present the first analysis of results from the SuperWASP Variable Stars Zooniverse project, which is aiming to classify 1.6 million phase-folded light curves of candidate stellar variables observed by the SuperWASP all sky survey with…

Solar and Stellar Astrophysics · Physics 2021-01-27 Heidi B. Thiemann , Andrew J. Norton , Hugh J. Dickinson , Adam McMaster , Ulrich C. Kolb

The Faint Sky Variability Survey is aimed at finding photometric and/or astrometric variable objects in the brightness range between 16<V<24 on timescales between tens of minutes and years with photometric precisions ranging from 3…

Astrophysics · Physics 2009-11-07 Paul J. Groot , Paul M. Vreeswijk , Mark E. Huber

We investigate magnetic activity properties of 21 stars via medium resolution optical spectra and long-term photometry. Applying synthetic spectrum fitting method, we find that all targets are cool giant or sub-giant stars possessing…

Solar and Stellar Astrophysics · Physics 2021-06-23 Orkun Özdarcan

Catalogs of periodic variable stars contain large numbers of periodic light-curves (photometric time series data from the astrophysics domain). Separating anomalous objects from well-known classes is an important step towards the discovery…

Machine Learning · Computer Science 2009-06-19 Umaa Rebbapragada , Pavlos Protopapas , Carla E. Brodley , Charles Alcock

A refined sample of 64 variable objects with stellar image structure has been identified in SA 57 to $B \sim 22.5$, over a time baseline of 15 years, sampled at 11 distinct epochs. The photometric data typically have a root-mean-square…

Astrophysics · Physics 2009-10-22 D. Trevese , R. G. Kron , S. R. Majewski , M. A. Bershady , D. C. Koo

We present a machine learning package for the classification of periodic variable stars. Our package is intended to be general: it can classify any single band optical light curve comprising at least a few tens of observations covering…

Instrumentation and Methods for Astrophysics · Physics 2016-02-17 Dae-Won Kim , Coryn A. L. Bailer-Jones

We monitored BL Lacertae frequently during 2014 - 2016 when it was generally in a high state. We searched for intra-day variability for 43 nights using quasi-simultaneous measurements in the B, V, R, and I bands (totaling 143 light curves);…

High Energy Astrophysical Phenomena · Physics 2017-12-20 Haritma Gaur , Alok C. Gupta , R. Bachev , A. Strigachev , E. Semkov , Paul J. Wiita , M. F. Gu , S. Ibryamov

Astronomical data are typically irregular in time, e.g. the space (HIPPARCOS/TYCHO, KEPLER, GAIA, WISE etc.) and ground-based CCD (NSVS, ASAS, CRTS, SuperWASP etc.) and photographic (Harvard, Sonneberg, Odessa etc.) photometrical surveys.…

Solar and Stellar Astrophysics · Physics 2019-02-05 Ivan L. Andronov

We investigate the use of optical photometric variability to select and identify blazars in large-scale time-domain surveys, in part to aid in the identification of blazar counterparts to the ~30% of gamma-ray sources in the Fermi 2FGL…

Until a few years ago, the amplitude variation in the photometric data had been limitedly explored mainly because of time resolution and photometric sensitivity limitations. This investigation is now possible thanks to the Kepler and CoRoT…

Solar and Stellar Astrophysics · Physics 2015-11-11 C. E. Ferreira Lopes , I. C. Leão , D. B. de Freitas , B. L. Canto Martins , M. Catelan , J. R. De Medeiros

Using light curves from the HATNet survey for transiting extrasolar planets we investigate the optical broad-band photometric variability of a sample of 27,560 field K and M dwarfs selected by color and proper-motion. A total of 2120 stars…

Solar and Stellar Astrophysics · Physics 2011-02-04 J. D. Hartman , G. Á. Bakos , R. W. Noyes , B. Sipöcz , G. Kovács , T. Mazeh , A. Shporer , A. Pál

We search a sample of 9,361,613 isolated sources with 13<g<14.5 mag for slowly varying sources. We select sources with brightness changes larger than ~ 0.03 mag/year over 10 years, removing false positives due to, for example, nearby bright…

Solar and Stellar Astrophysics · Physics 2025-01-27 Sydney Petz , Christopher S. Kochanek

The unprecedented precision of broadband stellar photometry achieved with the planet-hunting missions CoRoT and \textit{Kepler} initiated a new era in examining the magnetically-driven brightness variations of hundreds of thousands of…

Solar and Stellar Astrophysics · Physics 2021-06-25 Nina-Elisabet Nèmec

Recent quasar spectroscopy from the VLT and Keck telescopes suggests that fundamental constants may not actually be constant. To better confirm or refute this result, systematic errors between telescopes must be minimized. We present a new…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Tyler M. Evans , Michael T. Murphy

We study the relationship between the mid-infrared and sub-mm variability of deeply embedded protostars using the multi-epoch data from the Wide Infrared Survey Explorer ($WISE$/NEOWISE) and the ongoing James Clerk Maxwell Telescope (JCMT)…

The long-term optical and infrared color variability of blazars has been investigated with the SMARTS monitoring data. The sample in this study consists of 49 flat spectrum radio quasars and 22 BL Lac objects. The fractional variability…

Astrophysics of Galaxies · Physics 2015-11-11 Bing-Kai Zhang , Xiao-Shan Zhou , Xiao-Yun Zhao , Ben-Zhong Dai

High-precision time series have recently become available for many stars as a result of data from CoRoT, Kepler, and TESS and have been widely used to study stellar activity. They provide information integrated over the stellar disk, hence…

Solar and Stellar Astrophysics · Physics 2019-09-17 Nadege Meunier , Anne-Marie Lagrange

A comprehensive search for variable and transient radio sources has been conducted using ~55,000 snapshot images of the FIRST survey. We present an analysis leading to the discovery of 1,627 variable and transient objects down to mJy levels…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Nithyanandan Thyagarajan , David J. Helfand , Richard L. White , Robert H. Becker

We present HAWK-I J-band light curves of five late-type T dwarfs (T6.5-T7.5) with a typical duration of four hours, and investigate the evidence for quasi-periodic photometric variability on intra-night timescales. Our photometry reaches…

Solar and Stellar Astrophysics · Physics 2017-03-06 S. P. Littlefair , B. Burningham , Ch. Helling