ASASSN-15oi: a rapidly evolving, luminous tidal disruption event at 216 Mpc

By T. Holoien, C. Kochanek, J. Prieto, D. Grupe, Ping Chen, D. Godoy-Rivera, Krzysztof Zbigniew Stanek, B. Shappee, S. Dong, J. Brown and 10 more. 2016

133 citations recorded by the source corpus.

We present ground-based and Swift photometric and spectroscopic observations of the tidal disruption event (TDE) ASASSN-15oi, discovered at the center of 2MASX J20390918-3045201 ($d\simeq216$ Mpc) by the All-Sky Automated Survey for SuperNovae (ASAS-SN). The source peaked at a bolometric luminosity of $L\simeq1.9\times10^{44}$ ergs s$^{-1}$ and radiated a total energy of $E\simeq5.0\times10^{50}$ ergs over the $\sim3.5$ months of observations. The early optical/UV emission of the source can be fit by a blackbody with temperature increasing from $T\sim2\times10^4$ K to $T\sim6\times10^4$ K while the luminosity declines from $L\simeq1.9\times10^{44}$ ergs s$^{-1}$ to $L\simeq2.8\times10^{43}$ ergs s$^{-1}$, requiring the photosphere to be shrinking rapidly. The optical/UV luminosity decline is broadly consistent with an exponential decline, $L\propto e^{-t/t_0}$, with $t_0\simeq35$ days. ASASSN-15oi also exhibits roughly constant soft X-ray emission that is significantly weaker than the optical/UV emission. Spectra of the source show broad helium emission lines and strong blue continuum emission in early epochs, although these features fade rapidly and are not present $\sim3$ months after discovery. The early spectroscopic features and color evolution of ASASSN-15oi are consistent with a TDE, but the rapid spectral evolution is unique among optically-selected TDEs.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a233fd9e2dc4062c28bb6b2a5a4f6645c32a3bcb

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In Astronomy and Astrophysics

1. B. Metzger
2. E. Berger
3. Bing Zhang
4. E. Ramirez-Ruiz
5. E. Quataert
6. Masaomi Tanaka
7. T. Thompson
8. C. Kochanek

Citations in the corpus

• Revisiting Optical Tidal Disruption Events with iPTF16axa (2017, methodology): “A lower limit of 4.7 was reported for PS1-10jh (Gezari et al. 2015), a lower limit of ∼ 1 was reported for ASASSN-15oi (Holoien et al. 2016a), and we measure a lower limit of 1.9 for PTF09ge from fitting its spectrum obtained from the Double Spectrographmounted on the Palomar 200-inch (P200)…”
• A Unified Model for Tidal Disruption Events (2018, background): “Some of them produced prominent X-ray emission corresponding to ∼ 105K besides optical emission (Miller et al. 2015; Holoien et al. 2016b,a).”
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0 (2017, background): “Rarer extragalactic events are tidal disruption events (TDEs), where the majority of the best studied TDEs have been discovered by ASAS-SN (Holoien et al. 2014b, 2016a,b, Brown et al. 2016, 2017a) or are present in ASAS-SN (Brown et al. 2017b), and “changing-look” AGN (Shappee et al. 2014).”
• The fast, luminous ultraviolet transient AT2018cow: extreme supernova, or disruption of a star by an intermediate-mass black hole? (2018, methodology): “The spectral features in AT2018cow are substantially weaker than in the examples of TDEs that we are aware of (bottom panel of Figure 11; comparison spectra are from Holoien et al. 2014, 2016), but the resemblance to a TDE is much stronger than to any supernova.”
• New Physical Insights about Tidal Disruption Events from a Comprehensive Observational Inventory at X-Ray Wavelengths (2016, methodology): “For ASASSN15oi which was classified as an optical/UV TDE by Holoien et al. (2016a), the limited amount of data available make it is difficult to be able to quantify the evolution of the X-ray emission detected and based on the current results it does not decay significantly.”
• The Final Season Reimagined: 30 Tidal Disruption Events from the ZTF-I Survey (2022, background): “…with wide-field optical surveys at the forefront of these discoveries, including iPTF (Blagorodnova et al. 2017, 2019; Hung et al. 2017), ASAS-SN (Holoien et al. 2014, 2016a, 2016b, 2019b; Wevers et al. 2019; Hinkle et al. 2021a), Pan-STARRS (Gezari et al. 2012; Chornock et al. 2014; 22 Neil…”
• Weighing Black Holes Using Tidal Disruption Events (2018, background): “Finally, we note that the value from the literature for ASASSN-14li is dominated by systematic uncertainty not included in the quoted error (Holoien et al. 2016b).”