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SDSS image of the host galaxy NGC 3799 before the transient event occurs. The nucleus of the galaxy where the TDE occurred is marked with a green cross and is also shown in the enlarged inset in the upper right corner. credit: arXiv (2024). DOI: 10.48550/arxiv.2401.11773
An international team of astronomers conducted multiwavelength observations of AT 2023clx, the closest tidal disruption event (TDE) to Earth. As a result of the observation campaign, published January 22nd on preprint server arXivprovides important insights into the properties of this TDE.
A TDE is an astronomical phenomenon that occurs when a star passes close to a supermassive black hole and is pulled apart by the black hole’s tidal forces, triggering a process of destruction. As tidally disrupted stellar debris begins to rain down on the black hole, radiation is emitted from the innermost region of the accreting debris, indicating the presence of a TDE.
AT 2023clx, located approximately 155.8 million light-years away in the core of galaxy NGC 3799, is the closest known optical TDE. AT 2023clx was first identified as a transient phenomenon in 2014 and classified as a TDE in July 2023. With a maximum blackbody luminosity at the level of just 4.56 tredesillion ergs/sec, AT 2023clx is one of the faintest known tidal disruption events.
Given that AT 2023clx is a recently discovered TDE, little is known about its properties. That’s why a group of astronomers led by Panos Charalampopoulos from the University of Turku in Finland conducted extensive research on his TDE in the optical, near-infrared, and ultraviolet bands. For this purpose, they used various space telescopes and ground-based observation facilities, including his NASA Swift spacecraft and the Nordic Optical Telescope (NOT).
“In this paper, we present a follow-up study and thorough photometric and spectroscopic analysis of AT 2023clx,” the researchers wrote.
Observations revealed that AT 2023clx has a maximum absolute magnitude of -18.25 magnitude in the g-band and a maximum luminosity of 32.4 tredesillion erg/s. This results in a medium brightness TDE. The mass of a supermassive black hole is estimated to be about 1 million times the mass of the sun.
Research shows that AT 2023clx peaks within 10.4 days, making it the fastest rising TDE known to date. Astronomers assume that such a rapid rise was caused by the destruction of a very low-mass star (less than 0.1 solar mass) with a collision parameter of about 0.8.
Spectroscopy revealed a slowly cooling blue continuum and broad Balmer and helium lines, commonly observed in tidal disruption events. The line slowly thins over time as the luminosity decreases, which is also common in known TDEs.
Observations of AT 2023clx also found a sharp, narrow emission peak at the resting wavelength of about 6353 Å at the top of the blue side of the broad hydrogen alpha profile. This is the first time such a feature has been found in his TDE.
Summarizing the results, the researchers note that AT 2023clx is the result of tidal destruction of a low-mass, small-radius star, with a low central concentration, close to complete destruction but below a critical value. . They added that such disruptions should show a steeper rise and shallower decline in the light curve than other disturbances.
For more information:
P. Charalampopoulos et al., Fast transient AT 2023clx in the nearby liner galaxy NGC 3799 as a tidal disruption of very low-mass stars, arXiv (2024). DOI: 10.48550/arxiv.2401.11773
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