The X-Ray Imaging and Spectroscopy Mission (XRISM), a collaboration between JAXA, NASA, and ESA, has made a breakthrough in understanding cosmic winds. Using its high-resolution Resolve instrument, XRISM observed the neutron star GX13+1 on 25 February 2024, during a rare event when the system brightened beyond the Eddington limit (the maximum to the normal luminosity of stars). The resulting data revealed unexpectedly dense but surprisingly slow winds, challenging current models of how matter and energy interact in extreme environments. Unlike the ultrafast, clumpy winds observed near supermassive black holes, the GX13+1 winds were smooth and sluggish, raising new questions about the role of accretion disc temperature and radiation type in shaping wind properties. These findings may fundamentally alter our understanding of how such winds influence cosmic environments, from star formation to galactic evolution.

Artist's impression of the powerful winds blowing from the bright X-ray source GX13+1. The X-rays are coming from a disc of hot matter, known as an accretion disc, that is gradually spiralling down to strike a neutron star's surface. (Credit: ESA)

See more details at the ESA webpage:
https://www.esa.int/Science_Exploration/Space_Science/XRISM_uncovers_a_mystery_in_the_cosmic_winds_of_change

Paper Information

Journal： Nature
Title： Stratified wind from a super-Eddington X-ray binary is slower than expected
Authors： XRISM Collaboration
DOI： 10.1038/s41586-025-09495-w
URL：https://www.nature.com/articles/s41586-025-09495-w