Photometric and spectroscopic evolution of supernova SN 2009an: another case of a transitional Type Ia event

Sahu, D. K. ; Anupama, G. C. ; Anto, P. (2013) Photometric and spectroscopic evolution of supernova SN 2009an: another case of a transitional Type Ia event Monthly Notices of the Royal Astronomical Society, 430 (2). pp. 869-887. ISSN 0035-8711

[img]
Preview
PDF - Other
2MB

Official URL: http://mnras.oxfordjournals.org/content/early/2013...

Related URL: http://dx.doi.org/10.1093/mnras/sts609

Abstract

We present optical UBVRI photometry and medium-resolution spectroscopy of a transitional Type Ia supernova, SN 2009an, over the period −6 to ∼+150 d from the B maximum. With a Δm15(B) = 1.514 ± 0.132, SN 2009an declines faster than normal Type Ia events, but slower than the fast-declining, low-luminosity 1991bg-like events. The B-band absolute magnitude at maximum is −19.02 ± 0.20. The peak bolometric luminosity indicates that 0.41 M☉ of 56Ni was synthesized during the explosion. The pre-maximum and early post-maximum spectral evolution of SN 2009an is very similar to that in the transitional Type Ia SN 2004eo. High-velocity features in the Ca II near-infrared triplet are seen during the early phases. Similar to the other few objects belonging to this class, SN 2009an exhibits a higher value (~0.4) of the Si II line ratio R(Si II). The velocity gradient of the Si II 6355 Å line in the post-maximum epoch (v˙=60 km s−1 d−1) is at the boundary between the low-velocity-gradient and high-velocity-gradient groups.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
Keywords:Techniques: Photometric; Techniques: Spectroscopic; Supernovae: General; Supernovae: Individual: SN 2009an
ID Code:100486
Deposited On:10 Dec 2016 12:56
Last Modified:10 Dec 2016 12:56

Repository Staff Only: item control page