Einstein Probe may record first direct evidence of intermediate-mass black hole shredding a white dwarf
Astronomers may have caught a black hole of a size they have struggled for decades to prove exists. China's Einstein Probe recorded an X-ray outburst, EP250702a, that fits an intermediate-mass black hole shredding a white dwarf star. Over about 20 days it dimmed more than 100,000
Astronomers may have finally caught a kind of black hole they have spent decades trying to prove exists. China's Einstein Probe space telescope recorded a sudden, fierce burst of X-rays on the edge of a distant galaxy, an event now catalogued as EP250702a. After follow-up observations from telescopes around the world, the leading explanation is a black hole of intermediate mass tearing apart and swallowing a white dwarf star. The reading matters because it sits in a long-standing gap. Scientists routinely study small black holes left by collapsing stars and the giant ones at the centers of galaxies, but the in-between class has been remarkably hard to pin down. If the interpretation holds, this would be the first direct evidence of such a black hole feeding on a white dwarf. The signal itself was extreme. The source briefly ranked among the brightest instantaneous outbursts ever recorded, then faded by more than a hundred thousand times over roughly 20 days, while its X-rays shifted from higher to lower energy. The X-ray emission also appeared before the accompanying gamma-ray burst, an ordering that does not fit a standard explosion. The work, led by researchers at the National Astronomical Observatories of China with collaborators including the University of Hong Kong, was published as the cover article of Science Bulletin.