paper

Recurring tidal disruption events a decade apart in IRAS F01004-2237

arXiv:2410.09720 · doi:10.1051/0004-6361/202452380

Abstract

We report the discovery of a second optical flare that occurred in September 2021 in IRAS F01004-2237, where the first flare occurred in 2010 has been reported, and present a detailed analysis of multi-band data. The position of the flare coincides with the galaxy centre with a precision of 650 pc. The flare peaks in days with an absolute magnitude of and fades in two years roughly following . It maintains a nearly constant blackbody temperature of 22,000 K in the late time. Its optical and UV spectra show hydrogen and helium broad emission lines with full width at half maxima of 7,000--21,000 km s and He II/H ratio of 0.3--2.3. It shows weak X-ray emission relative to UV emission, with X-ray flares lasting for weeks, during which the spectrum is soft with a power-law index . These characters are consistent with a tidal disruption event (TDE), ruling out the possibilities of a supernova or an active galactic nuclei flare. With a TDE model, we infer a peak UV luminosity of erg s and an energy budget of erg. The two optical flares separated by years can be interpreted as repeating partial TDEs, double TDEs, or two independent TDEs. Although no definitive conclusion can be drawn, the partial TDEs interpretation predicts a third flare around 2033, and the independent TDEs interpretation predicts a high TDE rate of yr in F01004-2237, both of which can be tested by future observations.

arXiv comment22 pages, 16 figures, 9 tables, accepted for publication in A&A

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