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Related papers: BAT X-ray Survey - I: Methodology and X-ray Identi…

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We report on the spectral properties of a sample of 90 hard X-ray selected serendipitous sources detected in 12 XMM observations with 1<F(2-10)<80 10^(-14) erg/cm2/s. Approximately 40% of the sources are optically identified with 0.1<z<2…

Astrophysics · Physics 2009-11-10 E. Piconcelli , M. Cappi , L. Bassani , G. Di Cocco , M. Dadina

We present deep Swift follow-up observations of a sample of 94 unidentified X-ray sources from the XMM-Newton Slew Survey. The X-ray Telescope on-board Swift detected 29% of the sample sources; the flux limits for undetected sources…

High Energy Astrophysical Phenomena · Physics 2015-05-20 R. L. C. Starling , P. A. Evans , A. M. Read , R. D. Saxton , P. Esquej , H. Krimm , P. T. O'Brien , J. P. Osborne , S. Mateos , R. Warwick , K. Wiersema

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

Maximum-likelihood methods are applied to the problem of absorption tomography. The reconstruction is done with the help of an iterative algorithm. We show how the statistics of the illuminating beam can be incorporated into the…

Data Analysis, Statistics and Probability · Physics 2009-11-07 J. Rehacek , Z. Hradil , M. Zawisky , W. Treimer , M. Strobl

X-ray extragalactic surveys are ideal laboratories for the study of the evolution and clustering of active galactic nuclei (AGN). The XXL Survey spans two fields of a combined 50 $deg^2$ observed for more than 6Ms with XMM-Newton, occupying…

We describe a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray AGN. The defined sample has 1625 targets with radio and X-ray properties…

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

The Swift Burst Alert Telescope (BAT) is a coded aperture gamma-ray instrument with a large field of view that primarily operates in survey mode when it is not triggering on transient events. The survey data consists of eighty-channel…

High Energy Astrophysical Phenomena · Physics 2023-06-29 Tyler Parsotan , Sibasish Laha , David M. Palmer , Amy Lien , S. Bradley Cenko , Hans Krimm , Craig Markwardt

Observations of the gamma-ray sky with Fermi led to significant advances towards understanding blazars, the most extreme class of Active Galactic Nuclei. A large fraction of the population detected by Fermi is formed by BL Lacertae (BL Lac)…

The imaging atmospheric Cherenkov technique provides potentially the highest angular resolution achievable in astronomy at energies above the X-ray waveband. High-resolution measurements provide the key to progress on many of the major…

High Energy Astrophysical Phenomena · Physics 2024-06-26 Georg Schwefer , Robert Parsons , Jim Hinton

The BATSE mission aboard CGRO observed the whole sky for 9 years in the 20 keV - 2 MeV energy band. Flat-fielding of the temporal variations in the background present in the data set has been accomplished through a GEANT3 Monte-Carlo…

About 200 X-ray sources from a sample of spectrally hard ROSAT PSPC sources, given in the catalog of Haberl & Pietsch (1999), and observed in a ~60 square degree field of the LMC during several archival pointed observations with a wide…

Astrophysics · Physics 2009-11-07 P. Kahabka

The Burst and Transient Source Experiment (BATSE), aboard the Compton Gamma Ray Observatory (CGRO), provided a record of the low-energy gamma-ray sky (20-1000 keV) between 1991 April and 2000 May (9.1y). Using the Earth Occultation…

Context. Serendipitous X-ray surveys have proven to be an efficient way to find rare objects, for example tidal disruption events, changing-look active galactic nuclei (AGN), binary quasars, ultraluminous X-ray sources (ULXs), and…

High Energy Astrophysical Phenomena · Physics 2022-01-26 Hugo Tranin , Olivier Godet , Natalie Webb , Daria Primorac

We report results of a serendipitous hard X-ray (3--20 keV), nearly all-sky (|b|>10deg) survey based on RXTE/PCA observations performed during satellite reorientations in 1996--2002. The survey is 80% (90%) complete to a 4$\sigma$ limiting…

Astrophysics · Physics 2009-11-10 M. Revnivtsev , S. Sazonov , K. Jahoda , M. Gilfanov

Machine learning is an automatic technique that is revolutionizing scientific research, with innovative applications and wide use in astrophysics. The aim of this study was to developed an optimized version of an Artificial Neural Network…

High Energy Astrophysical Phenomena · Physics 2020-06-26 Miloš Kovačević , Graziano Chiaro , Sara Cutini , Gino Tosti

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

We present results of an all-sky hard X-ray survey based on almost four years of observations with the IBIS telescope on board the INTEGRAL observatory. The dead time-corrected exposure of the survey is ~33 Ms. Approximately 12% and 80% of…

Astrophysics · Physics 2009-11-13 R. Krivonos , M. Revnivtsev , A. Lutovinov , S. Sazonov , E. Churazov , R. Sunyaev

The Swift Burst Alert Telescope (BAT) is performing a high Galactic latitude survey in the 14-195 keV band at a flux limit of ~10^{-11} erg cm^{-2} s^{-1}, leading to the discovery of new high energy sources, most of which have not so far…