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Unsupervised clustering of Type II supernova light curves

Rubin, Adam and Gal-Yam, Avishay (2016) Unsupervised clustering of Type II supernova light curves. Astrophysical Journal, 828 (2). Art. No. 111. ISSN 1538-4357. https://resolver.caltech.edu/CaltechAUTHORS:20190604-131727395

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Abstract

As new facilities come online, the astronomical community will be provided with extremely large data sets of well-sampled light curves (LCs) of transients. This motivates systematic studies of the LCs of supernovae (SNe) of all types, including the early rising phase. We performed unsupervised k-means clustering on a sample of 59 R-band SN II LCs and find that the rise to peak plays an important role in classifying LCs. Our sample can be divided into three classes: slowly rising (II-S), fast rise/slow decline (II-FS), and fast rise/fast decline (II-FF). We also identify three outliers based on the algorithm. The II-FF and II-FS classes are disjoint in their decline rates, while the II-S class is intermediate and "bridges the gap." This may explain recent conflicting results regarding II-P/II-L populations. The II-FS class is also significantly less luminous than the other two classes. Performing clustering on the first two principal component analysis components gives equivalent results to using the full LC morphologies. This indicates that Type II LCs could possibly be reduced to two parameters. We present several important caveats to the technique, and find that the division into these classes is not fully robust. Moreover, these classes have some overlap, and are defined in the R band only. It is currently unclear if they represent distinct physical classes, and more data is needed to study these issues. However, we show that the outliers are actually composed of slowly evolving SN IIb, demonstrating the potential of such methods. The slowly evolving SNe IIb may arise from single massive progenitors.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/0004-637x/828/2/111DOIArticle
https://arxiv.org/abs/1602.01446arXivDiscussion Paper
ORCID:
AuthorORCID
Rubin, Adam0000-0003-4557-0632
Gal-Yam, Avishay0000-0002-3653-5598
Additional Information:© 2016 The American Astronomical Society. Received 2016 February 9; revised 2016 June 15; accepted 2016 June 16; published 2016 September 12. We thank Y. Cao for reducing the spectrum of iPTF13blq. We thank A. Tanay and B. Zackay for helpful discussions. A.G.Y. is supported by the EU/FP7 via ERC grant No. 307260, the Quantum universe I-CORE Program by the Israeli Committee for Planning and Budgeting and the Israel Science Foundation (ISF); by Minerva and ISF grants; by the Weizmann-UK "making connections" program; and by Kimmel and ARCHES awards.
Group:Palomar Transient Factory
Subject Keywords:supernovae: general
Issue or Number:2
Record Number:CaltechAUTHORS:20190604-131727395
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190604-131727395
Official Citation:Adam Rubin and Avishay Gal-Yam 2016 ApJ 828 111
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96111
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:04 Jun 2019 22:20
Last Modified:03 Oct 2019 21:19

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