The Palermo Swift-BAT hard X-ray catalogue. II. Results after 39 months of sky survey

<BR /> Aims We present the Palermo Swift-BAT hard X-ray catalogue obtained from the analysis of data acquired during the first 39 months of the Swift mission. <BR /> Methods We developed a dedicated software to perform the data reduction, mosaicking, and source detection of the BAT survey data. We analyzed the BAT dataset in three energy bands (14-150 keV, 14-30 keV, 14-70 keV), obtaining a list of 962 detections above a significance threshold of 4.8 standard deviations. The identification of the source counterparts was pursued using three strategies cross-correlation with published hard X-ray catalogues, analysis of field observations of soft X-ray instruments, and cross-correlation with SIMBAD databases. <BR /> Results The survey covers 90% of the sky down to a flux limit of 2.5 10<SUP>-11</SUP> erg cm<SUP>-2</SUP> s<SUP>-1</SUP> and 50% of the sky down to a flux limit of 1.8 10<SUP>-11</SUP> erg cm<SUP>-2</SUP> s<SUP>-1</SUP> in the 14-150 keV band. We derived a catalogue of 754 identified sources, of which ˜69% are extragalactic, ˜27% are Galactic objects, and ˜4% are already known X-ray or gamma ray emitters, whose nature has yet to be determined. The integrated flux of the extragalactic sample is ˜1% of the cosmic X-ray background in the 14-150 keV range. Table 2 is also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A href="http //cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A48">http //cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/510/A48</A>