HOLMBERG_IX_X-1
We propose a 90 ks XRISM observation of Holmberg IX X-1, a benchmark ultraluminous X-ray (ULX) source whose mechanical feedback, traced by a large ionized and optical and radio bubble, has yet to be directly linked to an active outflow. The source accretes persistently in the super-Eddington regime and is embedded in a bubble requiring substantial energy injection into the surrounding interstellar medium. However, the nature of the engine driving this feedback remains uncertain. A 90 ks Resolve exposure will either detect fast, highly ionized winds or place decisive limits on their kinetic power, allowing us to test whether present-day outflows can account for the observed bubble energetics and establish how ULXs impact their host galaxies.
obsid = 203148010 / Unique Observation/Sequence Number
object = HOLMBERG_IX_X-1 / Object name
pi_name = CHAKRABORTY PRIYANKA / Proposal Principal Investigator Name
ra = 149.471249054586 / Right Ascension (Pointing Position) (deg)
dec = 69.0636179364117 / Declination (Pointing Position) (deg)
roll_angle = 164.985325673999 / Roll Angle (deg)
start_time = 2026-09-03T06:45:04 / Start Time of the Observation
stop_time = 2026-09-05T06:16:04 / Stop Time of the Observation
exposure = 127315.89643 / Effective Total Observation Exposure (s)
public_date= 2099-12-31 / Public Date