The Neil Gehrels Swift Observatory

The Swift XRT 1SXPS Source Catalogue

Evans et al. (2014) published this catalog of point sources seen with the XRT (ADS).


We present the 1SXPS (Swift-XRT point source) catalog of 151,524 X-ray point sources detected by the Swift-XRT in 8 yr of operation. The catalog covers 1905 deg2 distributed approximately uniformly on the sky. We analyze the data in two ways. First we consider all observations individually, for which we have a typical sensitivity of ~3 x 10-13 erg cm-2 s-1 (0.3-10 keV). Then we co-add all data covering the same location on the sky: these images have a typical sensitivity of ~9 x 10-14 erg cm-2 s-1 (0.3-10 keV). Our sky coverage is nearly 2.5 times that of 3XMM-DR4, although the catalog is a factor of ~1.5 less sensitive. The median position error is 5.5″ (90% confidence), including systematics. Our source detection method improves on that used in previous X-ray Telescope (XRT) catalogs and we report ›68,000 new X-ray sources. The goals and observing strategy of the Swift satellite allow us to probe source variability on multiple timescales, and we find ~30,000 variable objects in our catalog. For every source we give positions, fluxes, time series (in four energy bands and two hardness ratios), estimates of the spectral properties, spectra and spectral fits for the brightest sources, and variability probabilities in multiple energy bands and timescales.


P. A. Evans1, J. P. Osborne1, A. P. Beardmore1, K. L. Page1, R. Willingale1 , C. J. Mountford1, C. Pagani1 , D. N. Burrows2, J. A. Kennea2, M. Perri3,4, G. Tagliaferri5, and N. Gehrels6

1Department of Physics and Astronomy, University of Leicester, X-ray and Observational Astronomy Group, University Road, Leicester, LE1 7RH, UK
2Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, Pennsylvania, PA 16802, USA
3ASI-Science Data Center, Via del Politecnico, I-00133 Rome, Italy
4INAF-Osservatorio Astronomico di Roma, Via Frascati 33, I-000040 Monteporzio Catone, Italy
5INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (LC), Italy
6NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA

Data Access

The catalog itself is available from this UKSSDC website.