Article open access publication

THE CARNEGIE SUPERNOVA PROJECT: INTRINSIC COLORS OF TYPE Ia SUPERNOVAE

The Astrophysical Journal, IOP Publishing, ISSN 1538-4357

Volume 789, 1, 2014

DOI:10.1088/0004-637x/789/1/32, Dimensions: pub.1020033027,

Affiliations

Organisations

  1. (1) Carnegie Observatories, grid.432988.c
  2. (2) Aarhus University, grid.7048.b, AU
  3. (3) Las Campanas Observatory, grid.440392.8
  4. (4) Kavli Institute for the Physics and Mathematics of the Universe, grid.440880.0
  5. (5) Texas A&M University, grid.264756.4

Description

We present an updated analysis of the intrinsic colors of Type Ia supernova (SNe Ia) using the latest data release of the Carnegie Supernova Project. We introduce a new light-curve parameter very similar to stretch that is better suited for fast-declining events, and find that these peculiar types can be seen as extensions to the population of "normal" SNe Ia. With a larger number of objects, an updated fit to the Lira relation is presented along with evidence for a dependence on the late-time slope of the B – V light-curves with stretch and color. Using the full wavelength range from u to H band, we place constraints on the reddening law for the sample as a whole and also for individual events/hosts based solely on the observed colors. The photometric data continue to favor low values of RV , though with large variations from event to event, indicating an intrinsic distribution. We confirm the findings of other groups that there appears to be a correlation between the derived reddening law, RV , and the color excess, E(B – V), such that larger E(B – V) tends to favor lower RV . The intrinsic u-band colors show a relatively large scatter that cannot be explained by variations in RV or by the Goobar power-law for circumstellar dust, but rather is correlated with spectroscopic features of the supernova and is therefore likely due to metallicity effects.

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Times Cited: 100

Field Citation Ratio (FCR): 21.88

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