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

description: 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 $45^{\circ}$.
description: 20 pages, 14 figures, 5 tables. Published in ApJ