A giant black hole ripped apart a star and then gorged on its remains for about a decade, according to an international team of astronomers, who published their discovery in the JournalNature Astronomytoday. The team involves a visiting professor from QianNan Normal University for Nationalities. The finding is based on the discovery of a very luminous and long-lasting flare of high-energy radiation, detected with space-based observatories: NASA’s Chandra X-ray Observatory and Swift satellite as well as ESA’s XMM-Newton.
The trio of orbiting X-ray telescopes found evidence for a “tidal disruption event” (TDE), wherein the tidal forces due to the intense gravity from a black hole can destroy an object – such as a star – that wanders too close. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest falls toward the black hole. As it travels inwards to be ingested by the black hole, the material heats up to millions of degrees and generates a distinct X-ray flare.
The extraordinary long bright phase of this event spanning over ten years means that among observed TDEs this was either the most massive star ever to be completely torn apart during one of these events, or the first where a smaller star was completely torn apart.
The event is located in a small galaxy about 1.8 billion light years from Earth. It was noted, when it became at least a factor 100 brighter in X-rays, and then remained at its remarkable brightness for more than a decade. The stream of stellar debris rapidly falls onto the black hole at a high rate, thereby feeding the black hole with the stellar remains.
This TDE may help answer the question as to how supermassive black holes in the early universe grow. If supermassive black holes can grow from TDEs or other means at a very fast rate, this could explain how supermassive black holes were able to reach masses about a billion times higher than the sun when the universe was only about a billion years old.
“In the near future, the world’s largest single-dish radio observatory,FAST, located in QianNan prefecture, can be used to study the radio signals from stellar disruptions by black holes,” said Dr. Ligong Mi, acting head of the newly established department of Physics and Astronomy at QNUN. The department was launched last March, just before the FAST inauguration, “It is likely, and would be our great honor, if such future discoveries will be made by some of the first astronomy students from QNUN at the home province of FAST”, added President (Yunhui) Shi from QNUN.
A paper describing the results appears in Nature Astronomy on February 6th and is available online https://arxiv.org/abs/1702.00792.
Contact for further information:
Dr. Dacheng Lin, email: firstname.lastname@example.org
First author of theNaturepublication
Dr. Stefanie Komossa, email:email@example.com
Visiting Professor at QNUN and co-author of the publication
Dr. Ligong MI, firstname.lastname@example.org
Acting Head, Department of Physics and Astronomy at QNUN
Press release image:
This artist’s illustration depicts what astronomers call a “tidal disruption event,” or TDE. This is when an object, such as a star, wanders too close to a black hole and is destroyed by tidal forces generated from the black hole’s intense gravitational forces. During a TDE, some of the stellar debris is flung outward at high speeds, while the rest (shown as the red material in the illustration) becomes hotter as it falls toward the black hole, generating a distinct X-ray flare. The two insets show the event at visible and X-ray light.
Image credit: CXC/M. Weiss; X-ray: NASA/CXC/UNH/D. Lin et al, Optical: CFHT