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The WISE and NEOWISE missions have provided the only mid-infrared all-sky time-domain data, opening a unique observational window for variability studies. Yet, a comprehensive and systematic catalog of mid-infrared variable sources has…

天体物理仪器与方法 · 物理学 2025-12-01 Zihan kang , Jingyi Zhang , Yanxia Zhang , Changhua Li , Xiao Kong , Minzhi Kong , Jinghang Shi , Shirui Wei , Xue-Bing Wu

Chandra observations of 17 nearby galaxies were analysed and 166 bright sources with X-ray counts > 100, were chosen for temporal analysis. Fractional root mean square variability amplitudes were estimated for lightcurves binned at ~ 4 ksec…

高能天体物理现象 · 物理学 2015-06-16 Soma Mandal , Ranjeev Misra , Gulab Dewangan

A number of deep, wide-field, near-infrared surveys employing new infrared cameras on 4m-class telescopes are about to commence. These surveys have the potential to determine the fraction of luminous dust-obscured quasars that may have…

天体物理学 · 物理学 2009-11-11 Natasha Maddox , Paul C. Hewett

We present a novel method for the light-curve characterization of Pan-STARRS1 Medium Deep Survey (PS1 MDS) extragalactic sources into stochastic variables (SV) and burst-like (BL) transients, using multi-band image-differencing time-series…

We have searched for variable stars in deep V-band images of a field towards the Galactic plane in Carina. The images were taken with VIMOS instrument at ESO VLT during 4 contiguous nights in April 2005. We detected 348 variables among…

太阳与恒星天体物理 · 物理学 2015-05-13 P. Pietrukowicz , D. Minniti , J. M. Fernandez , G. Pietrzynski , M. T. Ruiz , W. Gieren , R. F. Diaz , M. Zoccali , M. Hempel

We performed R-band time series observations of the young, metal rich open cluster NGC 2301 for 12 nights in Feb. 2004. B images were also obtained and color magnitude diagrams, having limits of R=19.5 and B=21.5, were produced. Only asmall…

天体物理学 · 物理学 2009-11-11 Steve B. Howell , Cassandra VanOutryve , John L. Tonry , Mark E. Everett , Raelin Schneider

A significant degree of misclassification of variable stars through the application of machine learning methods to survey data motivates a search for more reliable and accurate machine learning procedures, especially in light of the very…

太阳与恒星天体物理 · 物理学 2019-06-18 Refilwe Kgoadi , Chris Engelbrecht , Ian Whittingham , Andrew Tkachenko

The Gaia DR2 sample of short-timescale variable candidates results from the investigation of the first 22 months of Gaia photometry for a subsample of sources at the Gaia faint end. For this exercise, we limited ourselves to the case of…

At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt…

天体物理学 · 物理学 2007-05-23 Cesar Briceno

Wide-field time domain facilities detect transient events in large numbers through difference imaging. For example, Zwicky Transient Facility produces alerts for hundreds of thousands of transient events per night, a rate set to be dwarfed…

太阳与恒星天体物理 · 物理学 2022-10-12 D. Mistry , C. M. Copperwheat , M. J. Darnley , I. Olier

Blazars are a subclass of active galactic nuclei with relativistic jets pointing toward the observer. They are notable for their flux variability at all observed wavelengths and timescales. Together with simultaneous measurements at lower…

高能天体物理现象 · 物理学 2025-02-21 Hermann Stolte , Jonas Sinapius , Iftach Sadeh , Elisa Pueschel , Matthias Weidlich , David Berge

The light curves of variable stars are commonly described using simple trigonometric models, that make use of the assumption that the model parameters are constant in time. This assumption, however, is often violated, and consequently, time…

天体物理仪器与方法 · 物理学 2015-05-30 J. Pelt , N. Olspert , M. J. Mantere , I. Tuominen

Astronomy light curves are sparse, gappy, and heteroscedastic. As a result standard time series methods regularly used for financial and similar datasets are of little help and astronomers are usually left to their own instruments and…

Context. Quasars are spatially stationary, and they are essential objects in astrometry when defining reference frames. However, the census of quasars is far from complete. Mid-infared colors can be used to find quasar candidates because…

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…

太阳与恒星天体物理 · 物理学 2021-01-27 Heidi B. Thiemann , Andrew J. Norton , Hugh J. Dickinson , Adam McMaster , Ulrich C. Kolb

Gravitational lensing is proven to be one of the most efficient tools for studying the Universe. The spectral confirmation of such sources requires extensive calibration. This paper discusses the spectral extraction technique for the case…

We define a second-order moment of the observational differential microlensing curves that can be used to impose constraints on physical properties of lensed quasars. We show that this quantity is sensitive both to variations in the source…

星系天体物理 · 物理学 2021-05-11 Eduardo Guerras , Xinyu Dai , Evencio Mediavilla

This work is part of an effort to detect secular variable objects in large scale surveys by analysing their path in color-magnitude diagrams. To this aim, we first present the variability morphologies in the V/V-I diagram of several types…

太阳与恒星天体物理 · 物理学 2015-05-13 Maxime Spano , Nami Mowlavi , Laurent Eyer , Gilbert Burki

The ESA Gaia mission provides a unique time-domain survey for more than 1.6 billion sources with G ~ 21 mag. We showcase stellar variability across the Galactic colour-absolute magnitude diagram (CaMD), focusing on pulsating, eruptive, and…

We present ~47,000 periodic variables found during the analysis of 5.4 million variable star candidates within a 20,000 square degree region covered by the Catalina Surveys Data Release-1 (CSDR1). Combining these variables with type-ab RR…