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arXiv · 2108.13607

SN 2018agk: A Prototypical Type Ia Supernova with a Smooth Power-law Rise in Kepler (K2)

Abstract

We present the 30-min cadence Kepler/K2 light curve of the Type Ia supernova (SN Ia) SN 2018agk, covering approximately one week before explosion, the full rise phase and the decline until 40 days after peak. We additionally present ground-based observations in multiple bands within the same time range, including the 1-day cadence DECam observations within the first $\sim$5 days after the first light. The Kepler early light curve is fully consistent with a single power-law rise, without evidence of any bump feature. We compare SN 2018agk with a sample of other SNe~Ia without early excess flux from the literature. We find that SNe Ia without excess flux have slowly-evolving early colors in a narrow range ($g-i\approx -0.20\pm0.20$ mag) within the first $\sim 10$ days. On the other hand, among SNe Ia detected with excess, SN 2017cbv and SN 2018oh tend to be bluer, while iPTF16abc's evolution is similar to normal SNe Ia without excess in $g-i$. We further compare the Kepler light curve of SN 2018agk with companion-interaction models, and rule out the existence of a typical non-degenerate companion undergoing Roche-lobe overflow at viewing angles smaller than $45^{\circ}$.

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Qinan Wang, Armin Rest, Yossef Zenati, Ryan Ridden-Harper, Georgios Dimitriadis, Gautham Narayan, V. Ashley Villar, Mark R. Magee, Ryan J. Foley, Edward J. Shaya, Peter Garnavich, Lifan Wang, Lei Hu, Attila Bodi, Patrick Armstrong, Katie Auchettl, Thomas Barclay, Geert Barentsen, Zsófia Bognár, Joseph Brimacombe, Joanna Bulger, Jamison Burke, Peter Challis, Kenneth Chambers, David A. Coulter, Géza Csörnyei, Borbála Cseh, Maxime Deckers, Jessie L. Dotson, Lluís Galbany, Santiago González-Gaitán, Mariusz Gromadzki, Michael Gully-Santiago, Ottó Hanyecz, Christina Hedges, Daichi Hiramatsu, Griffin Hosseinzadeh, D. Andrew Howell, Steve B. Howell, Mark E. Huber, Saurabh W. Jha, David O. Jones, Réka Könyves-Tóth, Csilla Kalup, Charlie Kilpatrick, Levente Kriskovics, Wenxiong Li, Thomas B Lowe, Steven Margheim, Curtis McCully, Ayan Mitra, Jose A. Muñoz, Matt Nicholl, Jakob Nordin, András Pál, Yen-Chen Pan, Anthony L Piro, Sofia Rest, João Rino-Silvestre, César Rojas-Bravo, Krisztián Sárneczky, Matthew R. Siebert, Stephen J. Smartt, Ken Smith, Ádám Sódor, Maximilian D. Stritzinger, Róbert Szabó, Róbert Szakáts, Brad E. Tucker, József Vinkó, Xiaofeng Wang, J. Craig Wheeler, David R. Young, Alfredo Zenteno, Kaicheng Zhang, Gabriella Zsidi. 2021-08-31. SN 2018agk: A Prototypical Type Ia Supernova with a Smooth Power-law Rise in Kepler (K2). https://doi.org/10.3847/1538-4357/ac2c84

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