Quantitative Photospheric Spectral Analysis of the Type IIP Supernova 2007od

TL;DR

This study uses spectral analysis with PHOENIX and SYNOW codes to examine the early evolution of SN 2007od, confirming its classification as a normal Type II supernova and estimating its distance and explosion date.

Contribution

It provides a detailed spectral analysis of SN 2007od using advanced modeling codes, highlighting differences in line features and estimating key supernova parameters.

Findings

Identification of high velocity features in Hβ and Hα lines.

Consistent distance and explosion date estimates using SEAM.

Good agreement between models and observations despite some spectral peculiarities.

Abstract

We compare and analyze a time series of spectral observations obtained during the first 30 days of evolution of SN 2007od with the non-LTE code PHOENIX. Despite some spectroscopic particularities in the Balmer features, this supernova appears to be a normal Type II, and the fits proposed are generally in good agreement with the observations. As a starting point we have carried out an analysis with the parameterized synthetic spectrum code SYNOW to confirm line identifications and to highlight differences between the results of the two codes. The analysis computed using PHOENIX suggests the presence of a high velocity feature in H{\beta} and an H{\alpha} profile reproduced with a density profile steeper than that of the other elements. We also show a detailed analysis of the ions velocities of the 6 synthetic spectra. The distance is estimated for each epoch with the Spectral-fitting Expanding Atmosphere Method (SEAM). Consistent results are found using all the spectra which give the explosion date of JD 2454403 (29 October, 2007) and a distance modulus \mu = 32.2 \pm 0.3.