Discovery of a Mid-infrared Echo from the TDE Candidate in the Nucleus of ULIRG F01004-2237

May 2017 • 2017ApJ...841L...8D

Authors • Dou, Liming • Wang, Tinggui • Yan, Lin • Jiang, Ning • Yang, Chenwei • Cutri, Roc M. • Mainzer, Amy • Peng, Bo

Abstract • We present the mid-infrared (MIR) light curves (LCs) of a tidal disruption event candidate in the center of a nearby ultraluminous infrared galaxy F01004-2237 using archival WISE and NEOWISE data from 2010 to 2016. At the peak of the optical flare, F01004-2237 was IR quiescent. About three years later, its MIR fluxes have shown a steady increase, rising by 1.34 and 1.04 mag in 3.4 and 4.6 μm up to the end of 2016. The host-subtracted MIR peak luminosity is 2-3 × 10⁴⁴ erg s^-1. We interpret the MIR LCs as an infrared echo, I.e., dust reprocessed emission of the optical flare. Fitting the MIR LCs using our dust model, we infer a dust torus of the size of a few parsecs at some inclined angle. The derived dust temperatures range from 590-850 K, and the warm dust mass is ∼7 M _⊙. Such a large mass implies that the dust cannot be newly formed. We also derive the UV luminosity of 4-11 × 10⁴⁴ erg s^-1. The inferred total IR energy is 1-2 × 10⁵² erg, suggesting a large dust covering factor. Finally, our dust model suggests that the long tail of the optical flare could be due to dust scattering.

Links

View on ADS

IPAC Authors
(alphabetical)

Roc Cutri

IPAC Deputy Director