This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Astronomers have discovered a star being torn apart by a massive black hole more than 1,000 parsecs from the center of its host galaxy. The tidal disruption event, TDE 2023mfm, was first discovered by ZTF and then studied with a wide range of telescopes, including Keck, Lick, Hubble, Swift, Chandra, XMM-Newton and the VLA.
The discovery paper was posted to the arXiv preprint server on Sept. 28. Massive black holes typically lurk at the center of massive galaxies. Recently, a population of "wandering" black holes, existing far from galactic centers, has been uncovered.
They may end up in off-center regions because of gravitational-wave recoil, slingshot ejection, stalled orbital decay during galaxy mergers and long-lived massive black hole binaries or triples. Finding massive black holes located away from the centers of galaxies can help astronomers understand the population and evolution of lesser-explored intermediate-mass black holes and massive black holes. But they are hard to find because they are not actively feeding, so they produce no steady, detectable signal.
But sometimes, stars that get too close to black holes are ripped apart in a tidal disruption event (TDE), which can produce a debris stream. This results in a bright flash across different wavelengths and reveals the location of the wandering black hole. In this study led by Itai Sfaradi of the University of California, researchers present one such tidal disruption event, TDE 2023mfm, analyzed using optical and UV photometry with the Zwicky Transient Facility (ZTF), Hubble Space Telescope (HST) and Swift UVOT.
In addition, they used optical spectroscopy with Keck and Lick observatories, X-ray observations with Chandra and XMM-Newton, and multifrequency radio observations with the Very Large Array. The optical light curve reached a peak in 30 days and then slowly declined over 100 days. They fit the spectral energy distribution (SED), which shows how the source's light is spread across wavelengths.
Using this distribution in the optical and ultraviolet bands, they inferred a temperature of around 20,000 Kelvin, and it remained this hot for more than a month after the peak. The event took place 1.08 kiloparsecs (roughly 3,500 light-years) from the galaxy's center. The team did not find any X-ray emission from the TDE itself.
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