Details

Autor(en) / Beteiligte

• de Jaeger, T
• Anderson, J P
• Galbany, L
• González-Gaitán, S
• Hamuy, M
• Phillips, M M
• Stritzinger, M D
• Contreras, C
• Folatelli, G
• Gutiérrez, C P
• Hsiao, E Y
• Morrell, N
• Suntzeff, N B
• Dessart, L
• Filippenko, A V

Titel

Observed Type II supernova colours from the Carnegie Supernova Project-I

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2018-06, Vol.476 (4), p.4592-4616

Ort / Verlag

Oxford University Press

Erscheinungsjahr

2018

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Abstract We present a study of observed Type II supernova (SN II) colours using optical/near-infrared photometric data from the Carnegie Supernovae Project-I. We analyse four colours (B − V, u − g, g − r, and g − Y) and find that SN II colour curves can be described by two linear regimes during the photospheric phase. The first (s1, colour) is steeper and has a median duration of ∼40  d. The second, shallower slope (s2, colour) lasts until the end of the ‘plateau’ (∼80  d). The two slopes correlate in the sense that steeper initial colour curves also imply steeper colour curves at later phases. As suggested by recent studies, SNe II form a continuous population of objects from the colour point of view as well. We investigate correlations between the observed colours and a range of photometric and spectroscopic parameters including the absolute magnitude, the V-band light-curve slopes, and metal-line strengths. We find that less luminous SNe II appear redder, a trend that we argue is not driven by uncorrected host-galaxy reddening. While there is significant dispersion, we find evidence that redder SNe II (mainly at early epochs) display stronger metal-line equivalent widths. Host-galaxy reddening does not appear to be a dominant parameter, neither driving observed trends nor dominating the dispersion in observed colours. Intrinsic SN II colours are most probably dominated by photospheric temperature differences, with progenitor metallicity possibly playing a minor role. Such temperature differences could be related to differences in progenitor radius, together with the presence or absence of circumstellar material close to the progenitor stars.