THE WISE DETECTION OF AN INFRARED ECHO IN TIDAL DISRUPTION EVENT ASASSN-14li

• Published in: Astrophysical journal. Letters Vol. 828; no. 1; p. L14
• Main Authors: Jiang, Ning, Dou, Liming, Wang, Tinggui, Yang, Chenwei, Lyu, Jianwei, Zhou, Hongyan
• Format: Journal Article
• Language: English
• Published: United States The American Astronomical Society 01.09.2016
• Subjects: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BLACK HOLES; BOLOMETERS; COMPARATIVE EVALUATIONS; DETECTION; Disruption; Dust; DUSTS; EMISSION; EQUILIBRIUM; Flux; GALAXIES; galaxies: active; galaxies: individual (ASASSN-14li); galaxies: nuclei; GALAXY NUCLEI; Infrared; INFRARED SURVEYS; LUMINOSITY; REGENERATION; SUBLIMATION; Wide-field Infrared Survey Explorer
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8205/828/1/L14

ABSTRACT We report the detection of a significant infrared variability of the nearest tidal disruption event (TDE) ASASSN-14li using Wide-field Infrared Survey Explorer and newly released Near-Earth Object WISE Reactivation data. In comparison with the quiescent state, the infrared flux is brightened by 0.12 and 0.16 mag in the W1 (3.4 m) and W2 (4.6 m) bands at 36 days after the optical discovery (or ∼110 days after the peak disruption date). The flux excess is still detectable ∼170 days later. Assuming that the flare-like infrared emission is from the dust around the black hole, its blackbody temperature is estimated to be ∼2.1 × 103 K, slightly higher than the dust sublimation temperature, indicating that the dust is likely located close to the dust sublimation radius. The equilibrium between the heating and radiation of the dust claims a bolometric luminosity of ∼1043-1045 erg s−1, comparable with the observed peak luminosity. This result has for the first time confirmed the detection of infrared emission from the dust echoes of TDEs.