1SXPS: A deep Swift X-ray Telescope point source catalog with light curves and spectra

TL;DR

The 1SXPS catalog provides a comprehensive list of over 150,000 X-ray sources detected by Swift-XRT over 8 years, including their positions, spectra, and variability, significantly expanding previous X-ray source catalogs.

Contribution

This work introduces an improved detection method and presents the largest Swift-XRT point source catalog with detailed spectral and variability information.

Findings

Over 68,000 new X-ray sources identified

Median position error of 5.5 arcseconds

Detected ~30,000 variable objects

Abstract

We present the 1SXPS (Swift-XRT Point Source) catalog of 151,524 X-ray point-sources detected by the Swift-XRT in 8 years of operation. The catalog covers 1905 square degrees 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 ~3e-13 erg/cm2/s (0.3--10 keV). Then we co-add all data covering the same location on the sky: these images have a typical sensitivity of ~9e-14 erg/cm2/s (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 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.