학술논문
K2 Observations of SN 2018oh Reveal a Two-Component Rising Light Curve for a Type Ia Supernova
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Working Paper
Author
Dimitriadis, G.; Foley, R. J.; Rest, A.; Kasen, D.; Piro, A. L.; Polin, A.; Jones, D. O.; Villar, A.; Narayan, G.; Coulter, D. A.; Kilpatrick, C. D.; Pan, Y. -C.; Rojas-Bravo, C.; Fox, O. D.; Jha, S. W.; Nugent, P. E.; Riess, A. G.; Scolnic, D.; Drout, M. R.; Barentsen, G.; Dotson, J.; Gully-Santiago, M.; Hedges, C.; Cody, A. M.; Barclay, T.; Howell, S.; Garnavich, P.; Tucker, B. E.; Shaya, E.; Mushotzky, R.; Olling, R. P.; Margheim, S.; Zenteno, A.; Coughlin, J.; Van Cleve, J. E.; Cardoso, J. Vinicius de Miranda; Larson, K. A.; McCalmont-Everton, K. M.; Peterson, C. A.; Ross, S. E.; Reedy, L. H.; Osborne, D.; McGinn, C.; Kohnert, L.; Migliorini, L.; Wheaton, A.; Spencer, B.; Labonde, C.; Castillo, G.; Beerman, G.; Steward, K.; Hanley, M.; Larsen, R.; Gangopadhyay, R.; Kloetzel, R.; Weschler, T.; Nystrom, V.; Moffatt, J.; Redick, M.; Griest, K.; Packard, M.; Muszynski, M.; Kampmeier, J.; Bjella, R.; Flynn, S.; Elsaesser, B.; Chambers, K. C.; Flewelling, H. A.; Huber, M. E.; Magnier, E. A.; Waters, C. Z.; Schultz, A. S. B.; Bulger, J.; Lowe, T. B.; Willman, M.; Smartt, S. J.; Smith, K. W.; Points, S.; Strampelli, G. M.; Brimacombe, J.; Chen, P.; Munoz, J. A.; Mutel, R. L.; Shields, J.; Vallely, P. J.; Villanueva Jr, S.; Li, W.; Wang, X.; Zhang, J.; Lin, H.; Mo, J.; Zhao, X.; Sai, H.; Zhang, X.; Zhang, K.; Zhang, T.; Wang, L.; Baron, E.; DerKacy, J. M.; Li, L.; Chen, Z.; Xiang, D.; Rui, L.; Huang, F.; Li, X.; Hosseinzadeh, G.; Howell, D. A.; Arcavi, I.; Hiramatsu, D.; Burke, J.; Valenti, S.; Tonry, J. L.; Denneau, L.; Heinze, A. N.; Weiland, H.; Stalder, B.; Vinko, J.; Sarneczky, K.; Pa, A.; Bodi, A.; Bognar, Zs.; Csak, B.; Cseh, B.; Csornyei, G.; Hanyecz, O.; Ignacz, B.; Kalup, Cs.; Konyves-Toth, R.; Kriskovics, L.; Ordasi, A.; Rajmon, I.; Sodor, A.; Szabo, R.; Szakats, R.; Zsidi, G.; Williams, S. C.; Nordin, J.; Cartier, R.; Frohmaier, C.; Galbany, L.; Gutierrez, C. P.; Hook, I.; Inserra, C.; Smith, M.; Sand, D. J.; Andrews, J. E.; Smith, N.; Bilinski, C.
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Subject
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Abstract
We present an exquisite, 30-min cadence Kepler (K2) light curve of the Type Ia supernova (SN Ia) 2018oh (ASASSN-18bt), starting weeks before explosion, covering the moment of explosion and the subsequent rise, and continuing past peak brightness. These data are supplemented by multi-color Pan-STARRS1 and CTIO 4-m DECam observations obtained within hours of explosion. The K2 light curve has an unusual two-component shape, where the flux rises with a steep linear gradient for the first few days, followed by a quadratic rise as seen for typical SNe Ia. This "flux excess" relative to canonical SN Ia behavior is confirmed in our $i$-band light curve, and furthermore, SN 2018oh is especially blue during the early epochs. The flux excess peaks 2.14$\pm0.04$ days after explosion, has a FWHM of 3.12$\pm0.04$ days, a blackbody temperature of $T=17,500^{+11,500}_{-9,000}$ K, a peak luminosity of $4.3\pm0.2\times10^{37}\,{\rm erg\,s^{-1}}$, and a total integrated energy of $1.27\pm0.01\times10^{43}\,{\rm erg}$. We compare SN 2018oh to several models that may provide additional heating at early times, including collision with a companion and a shallow concentration of radioactive nickel. While all of these models generally reproduce the early K2 light curve shape, we slightly favor a companion interaction, at a distance of $\sim$$2\times10^{12}\,{\rm cm}$ based on our early color measurements, although the exact distance depends on the uncertain viewing angle. Additional confirmation of a companion interaction in future modeling and observations of SN 2018oh would provide strong support for a single-degenerate progenitor system.
Comment: 20 pages, 9 figures, 2 tables. Submitted to APJ Letters on 31 Jul 2018, Accepted for publication on 31 Aug 2018
Comment: 20 pages, 9 figures, 2 tables. Submitted to APJ Letters on 31 Jul 2018, Accepted for publication on 31 Aug 2018