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In October 2018, a small star was ripped to shreds when it wandered
too close to a black hole in a galaxy located 665 million light years
away from Earth.
A growing number of these so-called Tidal Disruption Events (TDEs) — when encroaching stars
are spaghettified by black holes — have been detected in recent years.
Cendes et al. present late-time radio/millimeter, optical/UV and
X-ray detections of tidal disruption event (TDE) AT2018hyz, spanning
970–1300 d after the optical discovery in 2018. In conjunction with earlier deeper
limits, the observations reveal rapidly
rising emission at 0.8–240 GHz. Such a steep rise cannot be explained in
any reasonable scenario of an outflow launched at the time of
disruption and instead points, unexpectedly, to a delayed launch.
Modeling of the multifrequency
data suggests that a mildly relativistic outflow
was launched -750 days after optical discovery.
This is the first definitive evidence for the production of a delayed mildly
relativistic outflow in a TDE.
The authors suggest that such delayed outflows may be common in TDEs.
The team collected observations of the TDE using the Australia Telescope Compact Array,
the Jansky Very Large Array in the USA, the ALMA Observatory in
Chile, MeerKAT in South Africa,
and the Chandra X-Ray Observatory and the Neil Gehrels
Swift Observatory in space.
The image above is an artist’s illustration of the tidal disruption event AT2019dsg.
(Image credit: DESY, Science Communication Lab.)
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