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The classification of the X-ray sources into classes (such as extragalactic sources, background stars, ...) is an essential task in astronomy. Typically, one of the classes corresponds to extragalactic radiation, whose photon emission…

Statistics Theory · Mathematics 2018-01-22 Amparo Baíllo , Javier Cárcamo , Konstantin V. Getman

We propose a novel statistical method to extend Fermi-LAT catalogues of high-latitude $\gamma$-ray sources below their nominal threshold. To do so, we rely on a recent determination of the differential source-count distribution of…

High Energy Astrophysical Phenomena · Physics 2024-05-16 Aurelio Amerio , Francesca Calore , Pasquale Dario Serpico , Bryan Zaldivar

Since its launch in 2008 the Fermi Large Area Telescope provides regular monitoring of a large sample of gamma-ray sources on time scales from hours to years. Together with observations at other wavelengths it is now possible to study…

High Energy Astrophysical Phenomena · Physics 2012-07-09 Stefan Larsson

We present a catalog of cross-correlated radio, infrared and X-ray sources using a very restrictive selection criteria with an IDL-based code developed by us. The significance of the observed coincidences was evaluated through Monte Carlo…

The rapid variability of X-ray binaries produces a wide range of X-ray states that are linked to activity across the electromagnetic spectrum. It is particularly challenging to study a sample of sources large enough to include all types in…

High Energy Astrophysical Phenomena · Physics 2023-06-30 John M. Dickey , S. D. Vrtilek , Michael McCollough , Bram Boroson , John A. Tomsick , Charles Bailyn , Jay M. Blanchard , Charlotte Johnson

We present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral shape and independent of temporal and…

Astrophysics · Physics 2008-12-18 H. -J. Grimm , J. McDowell , G. Fabbiano , M. Elvis

We describe a statistical method to avoid biased estimation of the content of different particle species. We consider the case when the particle identification information strongly depends on some kinematical variables, whose distributions…

Data Analysis, Statistics and Probability · Physics 2011-06-16 Massimo Casarsa , Pierluigi Catastini , Giovanni Punzi , Luciano Ristori

A large number of unidentified sources found by astronomical surveys and other observations necessitate the use of an automated classification technique based on machine learning methods. The aim of this paper is to find a suitable…

High Energy Astrophysical Phenomena · Physics 2023-02-20 Shivam Kumaran , Samir Mandal , Sudip Bhattacharyya , Deepak Mishra

X-ray sources with very few counts can be identified with low-noise X-ray detectors such as ACIS onboard the Chandra X-ray Observatory. These sources are often too faint for parametric spectral modeling using well-established methods such…

Solar and Stellar Astrophysics · Physics 2014-11-20 Konstantin V. Getman , Eric D. Feigelson , Patrick S. Broos , Leisa K. Townsley , Gordon P. Garmire

We present photometric redshifts for 1,031 X-ray sources in the X-ATLAS field, using the machine learning technique TPZ (Carrasco Kind & Brunner 2013). X-ATLAS covers 7.1 deg2 observed with the XMM-Newton within the Science Demonstration…

Astrophysics of Galaxies · Physics 2017-12-06 G. Mountrichas , A. Corral , V. A. Masoura , I. Georgantopoulos , A. Ruiz , A. Georgakakis , F. J. Carrera , S. Fotopoulou

Data selection and the determination of systematic uncertainties in the spectroscopic measurements of neutron star radii from thermonuclear X-ray bursts have been the subject of numerous recent studies. In one approach, the uncertainties…

High Energy Astrophysical Phenomena · Physics 2015-09-11 Feryal Ozel , Dimitrios Psaltis , Tolga Guver

The analysis of individual X-ray sources that appear in a crowded field can easily be compromised by the misallocation of recorded events to their originating sources. Even with a small number of sources, that nonetheless have overlapping…

Instrumentation and Methods for Astrophysics · Physics 2021-07-14 Antoine D. Meyer , David A. van Dyk , Vinay L. Kashyap , Luis F. Campos , David E. Jones , Aneta Siemiginowska , Andreas Zezas

With the availability of multiwavelength, multiscale and multiepoch astronomical catalogues, the number of features to describe astronomical objects has increases. The better features we select to classify objects, the higher the…

Astrophysics · Physics 2009-09-29 Y. Zhang , Y. Zhao , D. Gao

We review the current status of studies of large-scale structure in the X-ray Universe. After motivating the use X-rays for cosmological purposes, we discuss the various approaches used on different angular scales including X-ray background…

Astrophysics · Physics 2009-10-31 X. Barcons , F. J. Carrera , M. T. Ceballos , S. Mateos

We outline scientific objectives for monitoring X-ray sources and transients with wide-angle, coded mask cameras. It is now possible to instantaneously view half of the sky over long time intervals, gaining access to events of extraordinary…

High Energy Astrophysical Phenomena · Physics 2009-03-19 Ronald A. Remillard , Alan M. Levine , Jeffrey E. McClintock

This handbook chapter gives a modern introduction to spectral analysis of celestial X-ray sources. Concepts presented include the instrumentation response, the linear modelling approximation, Poisson count statistics and the Gaussian…

High Energy Astrophysical Phenomena · Physics 2023-09-13 Johannes Buchner , Peter Boorman

From optical spectroscopy of X-ray sources observed as part of ChaMP, we present redshifts and classifications for a total of 1569 Chandra sources from our targeted spectroscopic follow up using the FLWO, SAAO, WIYN, CTIO, KPNO, Magellan,…

We carry out classification of 4330 X-ray sources in the 2XMMi-DR3 catalog. They are selected under the requirement of being a point source with multiple XMM-Newton observations and at least one detection with the signal-to-noise ratio…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Dacheng Lin , Natalie A. Webb , Didier Barret

Transient radio signals of astrophysical origin present an avenue for studying the dynamic universe. With the next generation of radio interferometers being planned and built, there is great potential for detecting and studying large…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Cathryn M. Trott , Randall B. Wayth , Jean-Pierre R. Macquart , Steven J. Tingay

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.9 deg^2 of the COSMOS field down to limiting depths of 1.9 10^-16 erg cm^-2 s-1 in the 0.5-2 keV band, 7.3 10^-16 erg cm^-2 s^-1 in the…