XRT也有独立的暂现源了

We present the Living Swift-XRT Point Source Catalogue (LSXPS) and real-time transient detector. Uniquely among X-ray catalogues, LSXPS is updated in near real-time, making this the first up-to-date record of the point sources detected by a sensitive X-ray telescope: the Swift-X-ray Telescope (XRT). The associated upper limit calculator likewise makes use of all available data allowing contemporary upper limits to be rapidly produced. The combination of these two products, along with the rapid timescale on which XRT data are available, enables us to carry out for the first time low-latency searches for new transient X-ray events fainter than those available to the current generation of wide-field imagers. In this paper we describe the system and the classification and dissemination of transient alerts it generates.