A team of astronomers from the Raman Research Institute (RRI) has taken a closer look at one of the universe’s more puzzling phenomena — unpredictable bursts of high-energy radiation from a distant X-ray source — and uncovered clues that point to a dynamic, constantly shifting cosmic environment.
At the centre of this mystery lies a class of objects known as ultraluminous X-ray sources (ULXs). These systems are powered by extremely dense objects such as black holes or neutron stars that pull in matter from a nearby companion star. As this material spirals inward, it heats up and emits intense X-rays, making ULXs some of the brightest objects in the universe.
Breaking the Brightness Barrier Normally, celestial objects follow a natural brightness ceiling known as the Eddington limit, which depends on their mass. But ULXs defy this rule, shining far brighter — sometimes more than a hundred times beyond the expected limit. How they manage to sustain such extreme luminosity has remained an open question in astrophysics.
To investigate this, RRI researchers analysed a well-known ULX located in the spiral galaxy M74, called M74 X-1. This object had previously drawn attention for its sudden spikes in brightness, or “flares,” which occur roughly every 30 minutes — though not in a predictable pattern.
Using two decades’ worth of data from NASA’s Chandra X-ray Observatory and the European Space Agency’s XMM-Newton telescope, the team compared periods when the source was flaring with times when it was relatively calm.
A Tale of Two Views What they found was striking.
During flaring episodes, the X-ray spectrum showed a distinctive feature indicating the presence of powerful winds — streams o
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