ASASSN-14ko is a Periodic Nuclear Transient in ESO 253-G003
| Autor: | Payne, Anna V., Shappee, Benjamin J., Hinkle, Jason T., Vallely, Patrick J., Kochanek, Christopher S., Holoien, Thomas W. -S., Auchettl, Katie, Stanek, K. Z., Thompson, Todd A., Neustadt, Jack M. M., Tucker, Michael A., Armstrong, James D., Brimacombe, Joseph, Cacella, Paulo, Cornect, Robert, Denneau, Larry, Fausnaugh, Michael M., Flewelling, Heather, Grupe, Dirk, Heinze, A. N., Lopez, Laura A., Monard, Berto, Prieto, Jose L., Schneider, Adam C., Sheppard, Scott S., Tonry, John L., Weiland, Henry |
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| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/abe38d |
| Popis: | We present the discovery that ASASSN-14ko is a periodically flaring AGN at the center of the galaxy ESO 253-G003. At the time of its discovery by the All-Sky Automated Survey for Supernovae (ASAS-SN), it was classified as a supernova close to the nucleus. The subsequent six years of V- and g-band ASAS-SN observations reveal that ASASSN-14ko has nuclear flares occurring at regular intervals. The seventeen observed outbursts show evidence of a decreasing period over time, with a mean period of $P_0 = 114.2 \pm 0.4$ days and a period derivative of $\dot{P} = -0.0017\pm0.0003$. The most recent outburst in May 2020, which took place as predicted, exhibited spectroscopic changes during the rise and a had a UV bright, blackbody spectral energy distribution similar to tidal disruption events (TDEs). The X-ray flux decreased by a factor of 4 at the beginning of the outburst and then returned to its quiescent flux after ~8 days. TESS observed an outburst during Sectors 4-6, revealing a rise time of $5.60 \pm 0.05$ days in the optical and a decline that is best fit with an exponential model. We discuss several possible scenarios to explain ASASSN-14ko's periodic outbursts, but currently favor a repeated partial TDE. The next outbursts should peak in the optical on UT 2020-09-7.4$ \pm $1.1 and UT 2020-12-26.5$ \pm $1.4. Comment: 26 pages, 15 figures, 7 tables. Will be submitted to ApJ. The latest flare is currently ongoing, as we predicted |
| Databáze: | arXiv |
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