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The Kepler survey has provided a wealth of astrophysical knowledge by continuously monitoring over 150,000 stars. The resulting database contains thousands of examples of known variability types and at least as many that cannot be…

天体物理仪器与方法 · 物理学 2015-12-16 S. D. Kügler , N. Gianniotis , K. L. Polsterer

AIMS: We present a sample of candidate quasars selected using the KX-technique. The data cover 0.68 deg^2 of the X-ray Multi-Mirror (XMM) Large-Scale Structure (LSS) survey area where overlapping multi-wavelength imaging data permits an…

We present a variability, color and morphology based classifier, designed to identify transients, persistently variable, and non-variable sources, from the Zwicky Transient Facility (ZTF) Data Release 11 (DR11) light curves of extended and…

We present a variability study of 4646 massive stars in the Small Magellanic Cloud (SMC) with known spectral types from the catalog of Bonanos et al. (2010) using the light curves from the OGLE-III database. The goal is to exploit the time…

Quasars have long been known to be variable sources at all wavelengths. Their optical variability is stochastic, can be due to a variety of physical mechanisms, and is well-described statistically in terms of a damped random walk model. The…

Aims: During its all-sky survey phase, the eROSITA X-ray telescope onboard SRG scans through the ecliptic poles every 4 hours. This extensive data set of long-duration, frequent, and consistent observations of thousands of X-ray sources is…

天体物理仪器与方法 · 物理学 2024-07-03 David Bogensberger , Kirpal Nandra , Johannes Buchner

The time-series component of WISE is a valuable resource for the study of variable objects. We present an analysis of an all-sky sample of ~450,000 AllWISE+NEOWISE infrared light curves of likely variables identified in AllWISE. By…

太阳与恒星天体物理 · 物理学 2021-04-06 Evan Petrosky , Hsiang-Chih Hwang , Nadia L. Zakamska , Vedant Chandra , Matthew J. Hill

The second data release (DR2) of Gaia provides mean photometry in three bands for $\sim$1.4 billion sources, but light curves and variability properties are available for only $\sim$0.5 million of them. Here, we provide a census of…

We present optical lightcurves of variable stars consistent with the positions of X-ray sources identified with the Chandra X-ray Observatory for the Chandra Galactic Bulge Survey. Using data from the Mosaic-II instrument on the Blanco 4m…

We review some techniques to study the nature and size of the optical continuum sources in multiple QSOs. We focus on the source originating the events with several months timescale (the rapid variability source) as well as the source that…

天体物理学 · 物理学 2007-05-23 L. J. Goicoechea , D. Alcalde , V. N. Shalyapin

Variable stars play a very important role in our understanding of the Milky Way and the universe. In recent years, many survey projects have generated a large amount of photometric data, necessitating classifiers that can quickly identify…

天体物理仪器与方法 · 物理学 2025-02-27 Xiao-Hui Xu , Qing-Feng Zhu , Xu-Zhi Li , Hang Zheng , Jin-Sheng Qiu

Quasars have long been known as intrinsically variable sources, but the physical mechanism underlying the temporal optical/UV variability is still not well understood. We propose a novel nonparametric method for modeling and forecasting the…

Automatic classification methods applied to sky surveys have revolutionized the astronomical target selection process. Most surveys generate a vast amount of time series, or \quotes{lightcurves}, that represent the brightness variability of…

天体物理仪器与方法 · 物理学 2018-01-31 Nicolas Castro , Pavlos Protopapas , Karim Pichara

We search OGLE-I photometric database for stars, which, as defined by formal criteria adopted by OGLE-I microlensing search, showed variability during only one out of 3 or 4 observing seasons. The results include 17 previously reported…

天体物理学 · 物理学 2007-05-23 Przemyslaw Wozniak , Michal Szymanski

Statistical pattern recognition methods have provided competitive solutions for variable star classification at a relatively low computational cost. In order to perform supervised classification, a set of features is proposed and used to…

天体物理仪器与方法 · 物理学 2017-09-20 M. F. Pérez-Ortiz , A. García-Varela , A. J. Quiroz , B. E. Sabogal , J. Hernández

With the availability of large-scale surveys like Kepler and TESS, there is a pressing need for automated methods to classify light curves according to known classes of variable stars. We introduce a new algorithm for classifying light…

太阳与恒星天体物理 · 物理学 2022-06-30 Nicholas H. Barbara , Timothy R. Bedding , Ben D. Fulcher , Simon J. Murphy , Timothy Van Reeth

There have recently been several reports of apparently periodic variations in the light curves of quasars, e.g. PG 1302-102 by Graham et al. (2015a). Any quasar showing periodic oscillations in brightness would be a strong candidate to be a…

天体物理仪器与方法 · 物理学 2016-07-27 S. Vaughan , P. Uttley , A. G. Markowitz , D. Huppenkothen , M. J. Middleton , W. N. Alston , J. D. Scargle , W. M. Farr

The identification and analysis of different variable sources is a hot issue in astrophysical research. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) spectroscopic survey has accumulated massive spectral data but…

太阳与恒星天体物理 · 物理学 2022-03-02 Tingting Xu , Chao Liu , Feng Wang , Weirong Huang , Hui Deng , Ying Mei , Zhong Cao

The detection of rapid variability on a time-scale of hours in radio-quiet quasars (RQQSOs) could be a powerful discriminator between starburst, accretion disc and relativistic jet models of these sources. This paper contains an account of…

天体物理学 · 物理学 2009-10-30 M. Rabbette , B. McBreen , N. Smith , S. Steel

Visual classification of the variability classes of over 120,000 Kepler, K2 and TESS stars is presented. The sample is mainly based on stars with known spectral types. Since variability classification often requires the location of the star…

太阳与恒星天体物理 · 物理学 2023-08-16 Luis A. Balona