Swift BAT survey of AGNs

We present the results of the analysis of the first 9 months of data of the SwiftBAT survey of AGNs in the 14-195 keV band. Using archival X-ray data or follow-up Swift XRT observations, we have identified 129 ( 103 AGNs) of 130 objects detected at vertical bar b vertical bar > 15 degrees and with significance >4.8 sigma. One source remains unidentified. These same X-ray data have allowed measurement of the X-ray properties of the objects. We fit a power law to the log N-log S distribution, and find the slope to be 1.42 +/- 0.14. Characterizing the differential luminosity function data as a broken power law, we find a break luminosity log L-* (erg s(-1)) = 43.85 +/- 0.26, a low-luminosity power law slope a - 0.84(-0.22)(+0.16), and a high-luminosity power law slope b 2.55(-0.30)(+0.43) , similar to the values that have been reported based on INTEGRAL data. We obtain a mean photon index 1.98 in the 14-195 keV band, with an rms spread of 0.27. Integration of our luminosity function gives a local volume density of AGNs above 10(41) erg s(-1) of 2.4 x 10(-3) Mpc(-3), which is about 10% of the total luminous local galaxy density above M-* - -19.75. We have obtained X-ray spectra from the literature and from Swift XRT follow-up observations. These show that the distribution of log n(H) is essentially flat from nH = 10(20) to 10(24) cm(-2), with 50% of the objects having column densities of less than 10(22) cm(-2). BAT Seyfert galaxies have a median redshift of 0.03, a maximum log luminosity of 45.1, and approximately half have log n(H) > 22.