Observed Type II supernova colours from the Carnegie Supernova Project-I
We present a study of observed Type II supernova (SN II) colours using optical/near-infrared photometric data from the <i>Carnegie Supernovae Project-I</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 th...
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| Autores principales: | , , , , , , , , , , , , , , |
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| Formato: | Articulo Preprint |
| Lenguaje: | Inglés |
| Publicado: |
2018
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/93924 https://academic.oup.com/mnras/article-abstract/476/4/4592/4907983 https://ri.conicet.gov.ar/handle/11336/82472 |
| Aporte de: |
| Sumario: | We present a study of observed Type II supernova (SN II) colours using optical/near-infrared photometric data from the <i>Carnegie Supernovae Project-I</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 (s<sub>1,colour</sub>) is steeper and has a median duration of ∼ 40 days. The second, shallower slope (s<sub>2,colour</sub>) lasts until the end of the “plateau” (∼ 80 days). 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. |
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