English
Related papers

Related papers: Systematic evaluation of variability detection met…

200 papers

Context: In 6 years of operation, INTEGRAL/ISGRI revealed more than 500 sources. Many of these sources are variable. Taking into account that nearly half of INTEGRAL/ISGRI sources are new and many of them are still unidentified, the…

High Energy Astrophysical Phenomena · Physics 2015-05-18 I. Telezhinsky , D. Eckert , V. Savchenko , A. Neronov , N. Produit , T. J. -L. Courvoisier

We present an algorithm capable of detecting diffuse, dim sources of any size in an astronomical image. These sources often defeat traditional methods for source finding, which expand regions around points of high intensity. Extended…

Instrumentation and Methods for Astrophysics · Physics 2016-01-05 T. Butler-Yeoman , M. Frean , C. P. Hollitt , D. W. Hogg , M. Johnston-Hollitt

The PICsIT detector onboard the INTEGRAL satellite was designed to provide information about emission in the soft gamma-ray band for many bright sources. Due to strong and variable instrumental background, only 4 objects have been detected…

Astrophysics · Physics 2009-11-13 Piotr Lubinski

During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background…

We used the Aladin Virtual Obsrvatory tool and High Resolution Imager ROSAT archival data to search for X-ray variability in scale of days in 23 young stars in the sigma Orionis cluster and a background galaxy. Five stars displayed…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. A. Caballero , J. Lopez-Santiago , E. de Castro , M. Cornide

We have searched for extended X-ray sources in the ROSAT PSPC archive using the Voronoi Tesslation and Percolation algorithm (VTP). This algorithm detects all significant sources regardless of shape or size, and is particularly suited to…

Astrophysics · Physics 2007-05-23 L. R. Jones , C. A. Scharf , H. Ebeling , E. Perlman , M. Malkan , G. Wegner

Gamma-ray Bursts (GRBs) are highly energetic events that can be observed at extremely high redshift. However, inherent bias in GRB data due to selection effects and redshift evolution can significantly skew any subsequent analysis. We…

High Energy Astrophysical Phenomena · Physics 2021-11-23 Maria Dainotti , Delina Levine , Nissim Fraija , Poonam Chandra

We present a new method for determining the sensitivity of X-ray imaging observations, which correctly accounts for the observational biases that affect the probability of detecting a source of a given X-ray flux, without the need to…

Astrophysics · Physics 2009-11-13 A. Georgakakis , K. Nandra , E. S. Laird , J. Aird , M. Trichas

We present a statistical method based on a maximum likelihood approach to constrain the number counts of extragalactic sources below the nominal flux-density limit of continuum imaging surveys. We extract flux densities from a radio map…

Instrumentation and Methods for Astrophysics · Physics 2015-06-16 Ketron Mitchell-Wynne , Mario G. Santos , Jose Afonso , Matt J. Jarvis

Strong gravitational lens systems with extended sources are of special interest because they provide additional constraints on the models of the lens systems. To use a gravitational lens system for measuring the Hubble constant, one would…

Astrophysics · Physics 2009-11-11 S. H. Suyu , P. J. Marshall , M. P. Hobson , R. D. Blandford

The wavelet detection algorithm (WDA) described in the accompanying paper by Lazzati et al. is made suited for a fast and efficient analysis of images taken with the High Resolution Imager (HRI) instrument on board the ROSAT satellite. An…

Astrophysics · Physics 2009-10-31 Sergio Campana , Davide Lazzati , Maria Rosa Panzera , Gianpiero Tagliaferri

Thanks to the VISTA Variables in the Via Lactea (VVV) ESO Public Survey it is now possible to explore a large number of objects in those regions. This paper addresses the variability analysis of all VVV point sources having more than 10…

The process of determining the number and characteristics of sources in astronomical images is so fundamental to a large range of astronomical problems that it is perhaps surprising that no standard procedure has ever been defined that has…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 Minh Huynh , Andrew Hopkins , Ray Norris , Paul Hancock , Tara Murphy , Russell Jurek , Matthew Whiting

The detection and analysis of events within massive collections of time-series has become an extremely important task for time-domain astronomy. In particular, many scientific investigations (e.g. the analysis of microlensing and other…

Applications · Statistics 2013-01-22 Alexander W Blocker , Pavlos Protopapas

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 describe the method used to detect sources for the Herschel-ATLAS survey. The method is to filter the individual bands using a matched filter, based on the point-spread function (PSF) and confusion noise, and then form the inverse…

Instrumentation and Methods for Astrophysics · Physics 2020-02-26 S. J. Maddox , L. Dunne

This paper presents light curves and the first systematic characterization of variability of the 106 objects in the Fermi Large Area Telescope (LAT) Bright AGN Sample (LBAS). Weekly light curves obtained during the first 11 months of survey…

High Energy Astrophysical Phenomena · Physics 2015-05-18 A. A. Abdo

Spectral variability is the main tool for constraining emission models of BL Lac objects. By means of systematic observations of the BL Lac prototype PKS 2155-304 in the infrared-optical band, we explore variability on the scales of months,…

Strong lensed quasi-stellar objects (QSOs) are valuable probes of the universe in numerous aspects. Two of these applications, reverberation mapping and measuring time delays for determining cosmological parameters, require the source QSOs…

Astrophysics of Galaxies · Physics 2023-08-02 Yoon Chan Taak , Tommaso Treu