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

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 $\sim 50$ days with an absolute magnitude of $\sim -21$ and fades in two years roughly following $L\propto t^{-5/3}$. It maintains a nearly constant blackbody temperature of $\sim$22,000 K in the late time. Its optical and UV spectra show hydrogen and helium broad emission lines with full width at half maxima of 7,000--21,000 km s${}^{-1}$ and He II/H$\alpha$ ratio of 0.3--2.3. It shows weak X-ray emission relative to UV emission, with X-ray flares lasting for $<2-3$ weeks, during which the spectrum is soft with a power-law index $\Gamma =4.4_{-1.3}^{+1.4}$. 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 $3.3\pm 0.2\times 10^{44}$ erg s${}^{-1}$ and an energy budget of $4.5\pm 0.2\times 10^{51}$ erg. The two optical flares separated by $10.3\pm 0.3$ 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 $\gtrsim 10^{-2}$ yr${}^{-1}$ in F01004-2237, both of which can be tested by future observations.

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

References in corpus (28)

• The Host Galaxies and Classification of Active Galactic Nuclei
• A Catalog of Quasar Properties from SDSS DR7
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• An Observational Determination of the Bolometric Quasar Luminosity Function
• CASA, the Common Astronomy Software Applications for Radio Astronomy
• An online repository of Swift/XRT light curves of GRBs
• The Superluminous Transient ASASSN-15lh as a Tidal Disruption Event from a Kerr Black Hole
• Galaxies with Wolf-Rayet signatures in the low-redshift Universe - A survey using the Sloan Digital Sky Survey
• A Spitzer IRS Low-Resolution Spectroscopic Search for Buried AGNs in Nearby Ultraluminous Infrared Galaxies - A Constraint on Geometry between Energy Sources and Dust -
• Gaia Photometric Science Alerts
• A milliparsec supermassive black hole binary candidate in the galaxy SDSS J120136.02+300305.5
• A new class of flares from accreting supermassive black holes
• New changing look case in NGC 1566
• A population of highly energetic transient events in the centres of active galaxies
• AT2019azh: an unusually long-lived, radio-bright thermal tidal disruption event
• The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage
• IC 3599 did it again: A second outburst of the X-ray transient Seyfert 1.9 Galaxy
• Monthly quasi-periodic eruptions from repeated stellar disruption by a massive black hole
• Double tidal disruptions in galactic nuclei
• Distinguishing Tidal Disruption Events from Impostors
• Fallback Rates from Partial Tidal Disruption Events
• The rebrightening of a ROSAT-selected tidal disruption event: repeated weak partial disruption flares from a quiescent galaxy?
• AT 2019avd: A novel addition to the diverse population of nuclear transients
• X-ray flares from the stellar tidal disruption by a candidate supermassive black hole binary
• Discovery and Follow-up of the Unusual Nuclear Transient OGLE17aaj
• Rapid evolution of the recurrence time in the repeating partial tidal disruption event eRASSt J045650.3-203750
• Photospheric Velocity Gradients and Ejecta Masses of Hydrogen-poor Superluminous Supernovae -- Proxies for Distinguishing between Fast and Slow Events
• Spectroscopic monitoring of the candidate tidal disruption event in F01004-2237