Speaker
Description
The X-ray transient MAXI J1810-222 was discovered by MAXI in 2018 and has been active ever since. A long, combined radio and X-ray monitoring campaign was performed with ATCA and Swift, respectively. It gas been identified as a black hole candidate, even though the highly unusual outburst behaviour and the absence of information regarding the distance or the donor leaves the nature of the compact object open to ongoing debate. We detected a strong spectral absorption feature at ~1 keV with NICER which was described with a physical photoionization model. Through a deep scan of the parameters space, we found evidence for a spectral-state dependent outflow, with mildly relativistic speeds at 0.05-0.15 c. This finding would make MAXI J1810-222 the first X-ray binary where ultra-fast outflows have been detected at such high speeds. This is unlikely from classical thermal winds in Galactic X-ray binary and must involve either strong radiation or (most likely) a magnetically-driven wind. Motivated by this findings, we obtained a high quality XMM-Newton observation in 2023, in order to deeply investigate the nature of this absorption feature. I will present preliminary results of this observation.
