| 5th of March 2024 |
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| A radio flare associated with eRASSt J234403−352640: a potential tidal disruption event |
| by Goodwin et al. |
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When mass is suddenly accreted onto a super-massive black hole, the
release of gravitational energy powers some of the most explosive
phenomena in the Universe. Tidal Disruption Events (TDEs) are an
extreme example of this process, occurring when a star passes too
close to a supermassive black hole and is pulled apart by strong tidal
forces.
Goodwin et al. report the discovery, with the Australia Telescope
Compact Array, of a large-amplitude radio flare associated with the
nuclear transient event eRASSt J234402.9−352640, one of the most X-ray
luminous TDE candidates discovered by the SRG/eROSITA all-sky survey.
J2344 was first discovered on 2020 November 28 by the eROSITA
instrument as a bright, transient, ultra-soft X-ray source in the
second eROSITA all-sky survey. The nucleus of the host galaxy
brightened by a factor of at least 150 in the 0.2--2 keV X-ray band,
with the first X-ray detection occurring ∼20 d after the optical peak.
The ATCA observations reveal a radio flare lasting >1000 d, coincident with the X-ray, UV, optical, and infrared flare of this transient event. The radio emission is well-described by an expanding synchrotron emitting region, consisting of a single ejection of material launched coincident with the optical flare. The image above shows the ATCA 5 GHz radio light curve (top), WISE infrared light curve (middle), and ATLAS optical light curve (bottom). The timing of the radio peak and beginning of the optical rise are highlighted in grey-shaded regions, where the width of the region corresponds to the uncertainty in the time. The optical flare clearly leads the infrared and radio flares, respectively. |