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Paper: Application of Maximum Likelihood Method to the Swift/BAT Hard X-ray Survey: Preliminary Results
Volume: 380, At the Edge of the Universe: Latest Results from the Deepest Astronomical Surveys
Page: 163
Authors: Ajello, M.; Greiner, J.; Rau, A.; Kanbach, G.; Strong, A.W.; Tueller, J.; Markwardt, C.B.; Mushotzky, R.F.; Barthelmy, S.D.; Gehrels, N.
Abstract: The BAT instrument, on board the Swift observatory, is surveying the hard X-ray sky to unprecedented sensitivity. An implementation of Spatial Model fitting (Strong et al. 2005) is applied to BAT data. A test of this algorithm on a selected 90x90 deg2 field leads to the detection of 62 hard X-ray sources, of which, 30 are new and 20 are still unidentified, and a <1 mCrab sensitivity in less than 1 Ms exposure. The extragalactic source counts distribution (14-170 keV) is consistent with an Euclidean function and yields an AGN surface density of 0.0280.002 deg−2 above a limiting flux of 10−11erg cm−2 s−1. Moreover, BAT is a sensitive instrument for the detection of new Compton-thick objects because their emission peaks around 20,keV.
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