When a supermassive black gap consumes a star, it doesn’t simply swallow it complete. It shreds the star, ripping it aside little by little earlier than consuming the stays. It’s a messy course of often called a tidal disruption occasion (TDE). Astronomers often catch a glimpse of TDEs, and one current one has helped clear up a thriller a few sort of transient X-ray supply.
Often called quasi-periodic eruptions (QPEs), they’re delicate X-rays that emanate from the facilities of galaxies each few hours or just a few weeks. QPEs are uncommon, so they’re troublesome to check, and we aren’t positive what causes them. One concept is that they’re attributable to a big star or stellar black gap orbiting the supermassive black gap in such a approach that its orbit intersects with the accretion disk of the supermassive black gap. Every time the smaller object passes by means of the disk, it triggers superheated plasma to launch X-rays. We’ve seen a comparable impact with blazars, for instance.
Given the brief periodicity of QPEs the companion object would wish to orbit the black gap very intently, simply on the sting of a secure orbit distance. And when it begins intersecting with accretion disk materials, its orbit will decay on a brief cosmic timescale. This could clarify why QPEs are so uncommon. However to show this mannequin, astronomers would wish to look at this taking place in actual time, which is what a crew of astronomers has not too long ago completed. The outcomes shall be printed in Nature later this month.
The story begins with an remark by the Zwicky Transient Facility again in 2019. The ZTF captured an optical flare that had all of the markings of a tidal disruption occasion. It got here to be often called TDE AT2019qiz. In response to black gap fashions, when a star is ripped aside, a lot of the fabric kinds an accretion disk across the black gap inside just a few years. This could make for good QPE situations if there was an in depth companion object. So the crew aimed the Chandra X-ray Observatory at AT2019qiz often, hoping to seize a quasi-periodic eruption. Certain sufficient, in 2023, the crew began to look at X-ray flashes erupting about each 48 hours. Observations from the Swift and AstroSAT telescopes additional confirmed the consequence.
It isn’t recognized whether or not the companion is a star or small black gap, and the crew wish to seize extra QPEs occurring after recognized tidal disruption occasions, however this preliminary result’s fairly clear.
Reference: Nicholl, M., et al. “Quasi-periodic X-ray eruptions years after a close-by tidal disruption occasion.” arXiv preprint arXiv:2409.02181 (2024).
