A1 Refereed original research article in a scientific journal
K2 Observations of SN 2018oh Reveal a Two-component Rising Light Curve for a Type Ia Supernova
Authors: Dimitriadis G, Foley RJ, Rest A, Kasen D, Piro AL, Polin A, Jones DO, Villar A, Narayan G, Coulter DA, Kilpatrick CD, Pan YC, Rojas-Bravo C, Fox OD, Jha SW, Nugent PE, Riess AG, Scolnic D, Drout MR, Barentsen G, Dotson J, Gully-Santiago M, Hedges C, Cody AM, Barclay T, Howell S, Garnavich P, Tucker BE, Shaya E, Mushotzky R, Olling RP, Margheim S, Zenteno A, Coughlin J, Van Cleve JE, Cardoso JVD, Larson KA, McCalmont-Everton KM, Peterson CA, Ross SE, Reedy LH, 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 KC, Flewelling HA, Huber ME, Magnier EA, Waters CZ, Schultz ASB, Bulger J, Lowe TB, Willman M, Smartt SJ, Smith KW, Points S, Strampelli GM, Brimacombe J, Chen P, Munoz JA, Mutel RL, Shields J, Vallely PJ, Villanueva S, Li W, Wang X, Zhang J, Lin H, Mo J, Zhao X, Sai H, Zhang X, Zhang K, Zhang T, Wang L, Zhang J, Baron E, DerKacy JM, Li L, Chen Z, Xiang D, Rui L, Wang L, Huang F, Li X, Hosseinzadeh G, Howell DA, Arcavi I, Hiramatsu D, Burke J, Valenti S, Tonry JL, Denneau L, Heinze AN, Weiland H, Stalder B, Vinko J, Sarneczky K, Pal A, Bodi A, Bognar Z, Csak B, Cseh B, Csornyei G, Hanyecz O, Ignacz B, Kalup C, Konyves-Toth R, Kriskovics L, Ordasi A, Rajmon I, Sodor A, Szabo R, Szakats R, Zsidi G, Williams SC, Nordin J, Cartier R, Frohmaier C, Galbany L, Gutierrez CP, Hook I, Inserra C, Smith M, Sand DJ, Andrews JE, Smith N, Bilinski C
Publisher: IOP PUBLISHING LTD
Publication year: 2019
Journal: Astrophysical Journal Letters
Journal name in source: ASTROPHYSICAL JOURNAL LETTERS
Journal acronym: ASTROPHYS J LETT
Article number: ARTN L1
Volume: 870
Number of pages: 16
ISSN: 2041-8205
eISSN: 2041-8213
DOI: https://doi.org/10.3847/2041-8213/aaedb0
We present an exquisite 30 minute 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 Panoramic Survey Telescope (Pan-STARRS1) and Rapid Response System 1 and Cerro Tololo Inter-American Observatory 4 m Dark Energy Camera (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 supernovae (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 +/- 0.04 days after explosion, has a FWHM of 3.12 +/- 0.04 days, a blackbody temperature of T=17,500(-9,000)(+11,500) K, a peak luminosity of 4.3 +/- 0.2 x 10(37) erg s(-1), and a total integrated energy of 1.27 +/- 0.01 x 10(43) 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 similar to 2x10(12) 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.
