Science Results XRISM uncovers a mystery in the cosmic winds of change

2025.09.18

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)

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 luminosity a star (or accreting object) can have before the outward pressure of radiation balances and halts the inward pull of gravity). 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.

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

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

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