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Anomalous extinction behaviour towards the Type Ia SN 2003cg

N. Elias-Rosa·S. Benetti·E. Cappellaro·M. Turatto·P. A. Mazzali·F. Patat·W. P. S. Meikle·M. Stehle·A. Pastorello·G. Pignata·R. Kotak·A. Harutyunyan·G. Altavilla·H. Navasardyan·Y. Qiu·M. E. Salvo·W. Hillebrandt
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Abstract

We present optical and near-infrared photometry and spectroscopy of the Type Ia SN 2003cg, which exploded in the nearby galaxy NGC 3169. The observations cover a period between -8.5 and +414 days post-maximum. SN 2003cg is a normal but highly-reddened Type Ia event. Its B magnitude at maximum B_max = 15.94+/-0.04 and Delta m_15(B)_obs = 1.12+/-0.04 (Delta m_15(B)_intrinsic = 1.25+/-0.05). Allowing R_v to become a free parameter within the Cardelli et al. (1989) extinction law, simultaneous matches to a range of colour curves of normal SNe Ia yielded E(B-V) = 1.33+/-0.11, and R_v = 1.80+/-0.19. While the value obtained for R_v is small, such values have been invoked in the past, and may imply a grain size which is small compared with the average value for the local ISM.

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N. Elias-Rosa, S. Benetti, E. Cappellaro, M. Turatto, P. A. Mazzali, F. Patat, W. P. S. Meikle, M. Stehle, A. Pastorello, G. Pignata, R. Kotak, A. Harutyunyan, G. Altavilla, H. Navasardyan, Y. Qiu, M. E. Salvo, W. Hillebrandt. 2006-03-31. Anomalous extinction behaviour towards the Type Ia SN 2003cg. https://doi.org/10.1111/j.1365-2966.2006.10430.x

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