Why in news?
Astronomers confirmed a Be/X-ray binary pulsar within the Magellanic Bridge.
The source is named eRASSU J012422.9−724248 and lies near the Small Magellanic Cloud's eastern wing.
It is the first confirmed system of this particular class inside the Bridge.
The finding used archived extended ROentgen Survey with an Imaging Telescope Array (eROSITA) observations.
Background
The Large and Small Magellanic Clouds are irregular dwarf galaxies near the Milky Way.
They are prominent southern-sky objects and interact gravitationally with each other.
The Magellanic Bridge is a stream of gas and young stars connecting these galaxies.
A close galactic encounter stripped material and helped create the connecting structure.
The Bridge therefore provides a natural laboratory for studying star formation after galactic interactions.
What is a Be/X-ray binary?
A binary system contains two objects orbiting their shared centre of mass.
Here, one member is a rapidly rotating, hot Be-type star.
Such stars possess characteristic emission lines and a surrounding disc of expelled gas.
The companion is a neutron star, which is an extremely dense stellar remnant.
Gas captured by the neutron star becomes hot and releases energetic X-rays.
A rotating magnetic neutron star directs radiation into beams, creating regular X-ray pulses.
How was the system confirmed?
The first four eROSITA all-sky surveys revealed the previously unknown X-ray source.
Researchers then combined observations from eROSITA, Swift and the Nuclear Spectroscopic Telescope Array.
They added optical data from the Optical Gravitational Lensing Experiment and Las Cumbres Observatory.
The measurements confirmed a neutron-star spin period of 341.71 seconds.
Fifteen years of optical monitoring suggested an orbital period of 63.65 days.
The team proposed that the source belongs to the persistent Be/X-ray binary class.
What is eROSITA?
The name expands to extended ROentgen Survey with an Imaging Telescope Array.
Germany's Max Planck Institute for Extraterrestrial Physics led the telescope's development.
It launched aboard the Russian-German Spektrum-Roentgen-Gamma mission on 13 July 2019.
The telescope completed four full sky scans and part of a fifth scan.
It entered safe mode on 26 February 2022 and has not resumed science operations.
Why is the discovery important?
The system tests how massive binaries survive material stripping and changing galactic environments.
It also permits comparisons between stars in the Bridge and both Magellanic Clouds.
The finding is the Bridge's first confirmed Be/X-ray binary pulsar, not the world's first.
Conclusion
The new pulsar connects compact-star physics with the larger history of interacting nearby galaxies.