Astronomers discover new supergiant fast X-ray transient, expanding rare class

"Italian astronomers report the detection of a new X-ray binary (XRB), which has received the designation 4XMM J181330.1-17511 (J1813 for short). The newfound object represents the rare subclass of XRBs known as supergiant fast X-ray transients. The discovery is detailed in a research paper published March 6 on the arXiv preprint server."

The paper is at https://arxiv.org/abs/2503.04009.

I've been long fascinated by odd astronomical items like this, particularly since I heard Joe Taylor play an audio tape of various frequencies that quasars pulsed at.