Detection of extended X-rays around microquasar V4641 Sgr with XRISM

Microquasar V4641 Sagitarii (Sgr) is now of great interest as an efficient cosmic-ray factory, because of the recent discovery of very high energy, extended gamma-ray emission around it with HAWC and LHAASO. Occasionally, XRISM observed this source on Sep 30 as a “generic ToO” target, following its recent outburst. The large field of view and low background of Xtend imager did an amazing job in detecting a faint, extended X-ray emission around the source in spite of the small effective exposure time, 12 ks. The extended gamma-ray and X-ray emission, which is reminiscent of the SS433/W50 system, provide valuable information of its particle acceleration environment. The paper is now published in ApJL (ADS).