TY - JOUR
T1 - K2 Observations of SN 2018oh Reveal a Two-component Rising Light Curve for a Type Ia Supernova
AU - Konkoly
AU - ePESSTO
AU - University of Arizona
AU - K2 Mission Team
AU - Kegs
AU - Kepler Spacecraft Team
AU - Pan-STARRS
AU - Decam
AU - ASAS-SN
AU - Ptss/tnts
AU - Las Cumbres Observatory
AU - ATLAS
AU - Dimitriadis, G.
AU - Foley, R. J.
AU - Rest, A.
AU - Kasen, D.
AU - Piro, A. L.
AU - Polin, A.
AU - Jones, D. O.
AU - Villar, A.
AU - Narayan, G.
AU - Coulter, D. A.
AU - Kilpatrick, C. D.
AU - Pan, Y. C.
AU - Rojas-Bravo, C.
AU - Fox, O. D.
AU - Jha, S. W.
AU - Nugent, P. E.
AU - Riess, A. G.
AU - Scolnic, D.
AU - Drout, M. R.
AU - Barentsen, G.
AU - Dotson, J.
AU - Gully-Santiago, M.
AU - Hedges, C.
AU - Cody, A. M.
AU - Barclay, T.
AU - Howell, S.
AU - Garnavich, P.
AU - Tucker, B. E.
AU - Shaya, E.
AU - Mushotzky, R.
AU - Olling, R. P.
AU - Margheim, S.
AU - Zenteno, A.
AU - Coughlin, J.
AU - Cleve, J. E.Van
AU - De Miranda Cardoso, J. Vinícius
AU - Larson, K. A.
AU - McCalmont-Everton, K. M.
AU - Peterson, C. A.
AU - Ross, S. E.
AU - Reedy, L. H.
AU - Osborne, D.
AU - McGinn, C.
AU - Kohnert, L.
AU - Migliorini, L.
AU - Wheaton, A.
AU - Spencer, B.
AU - Labonde, C.
AU - Castillo, G.
AU - Beerman, G.
N1 - Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved..
PY - 2019/1/1
Y1 - 2019/1/1
N2 - 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 K, a peak luminosity of , and a total integrated energy of . 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 ∼ 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.
AB - 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 K, a peak luminosity of , and a total integrated energy of . 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 ∼ 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.
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U2 - 10.3847/2041-8213/aaedb0
DO - 10.3847/2041-8213/aaedb0
M3 - Article
AN - SCOPUS:85059854261
SN - 2041-8205
VL - 870
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L1
ER -