Astronomers from across the globe have embarked on a comprehensive investigation of AT 2023clx, an extraordinary tidal disruption event (TDE) that stands as the closest optical phenomenon of its kind to Earth. Published on the arXiv pre-print server on January 22, the findings from this multiwavelength observation campaign offer valuable insights into the characteristics of this unique celestial event.
TDEs represent captivating astronomical occurrences triggered when a star ventures too close to a supermassive black hole, succumbing to the immense tidal forces exerted by the black hole's gravitational pull. As the star undergoes disruption, its fragmented remnants cascade towards the black hole, emitting radiation from the innermost region of the accreting debris—a telltale sign of a TDE.
Nestled within the nucleus of the galaxy NGC 3799, approximately 155.8 million light-years distant, AT 2023clx emerged as a transient spectacle in 2014, eventually classified as a TDE in July 2023. Despite its proximity, AT 2023clx boasts a subdued luminosity, with a maximum blackbody output measuring a mere 4.56 tredecillion erg/s, rendering it one of the dimmest known TDEs.
Due to its recent discovery, AT 2023clx remains shrouded in mystery, prompting a consortium of astronomers led by Panos Charalampopoulos from the University of Turku in Finland to embark on an exhaustive investigation across optical, near-infrared, and ultraviolet wavelengths. Leveraging an array of space telescopes and ground-based observatories—including NASA's Swift spacecraft and the Nordic Optical Telescope (NOT)—the researchers conducted a meticulous analysis of AT 2023clx.
Their observations unveiled intriguing details about AT 2023clx, including its peak absolute magnitude of -18.25 mag in the g-band and a maximum bolometric luminosity reaching 32.4 tredecillion erg/s, positioning it as an intermediate luminosity TDE. Estimates suggest a supermassive black hole with a mass in the order of 1 million solar masses presides at the core of NGC 3799.
Of particular note is the rapid ascent of AT 2023clx to its peak within a mere 10.4 days, marking it as the swiftest rising TDE on record. Spectroscopic analyses revealed distinctive features, including a cooling blue continuum and broad Balmer and helium lines, characteristic of tidal disruption events. Notably, a novel emission peak detected at a rest wavelength of approximately 6353 Å atop the hydrogen-alpha profile represents a first-time observation in a TDE.