Abstract:
We present 1D non-local thermodynamic equilibrium (non-LTE)
time-dependent radiative-transfer simulations of a Chandrasekhar-mass
delayed-detonation model which synthesizes 0.51 Msun of 56Ni, and
confront our results to the Type Ia supernova (SN Ia) 2002bo over the
first 100 days of its evolution. Assuming only homologous expansion,
this same model reproduces the bolometric and multi-band light curves,
the secondary near-infrared (NIR) maxima, and the optical and NIR
spectra. The chemical stratification of our model qualitatively
agrees with previous inferences by Stehle et al., but reveals
significant quantitative differences for both iron-group and
intermediate-mass elements. We show that +/-0.1 Msun (i.e., +/-20 per
cent) variations in 56Ni mass have a modest impact on the bolometric
and colour evolution of our model. One notable exception is the
U-band, where a larger abundance of iron-group elements results in
less opaque ejecta through ionization effects, our model with more
56Ni displaying a higher near-UV flux level. In the NIR range, such
variations in 56Ni mass affect the timing of the secondary maxima but
not their magnitude, in agreement with observational
results. Moreover, the variation in the I, J, and K_s magnitudes is
less than 0.1 mag within ~10 days from bolometric maximum, confirming
the potential of NIR photometry of SNe Ia for cosmology. Overall, the
delayed-detonation mechanism in single Chandrasekhar-mass white dwarf
progenitors seems well suited for SN 2002bo and similar SNe Ia
displaying a broad Si II 6355 A line. Whatever multidimensional
processes are at play during the explosion leading to these events,
they must conspire to produce an ejecta comparable to our
spherically-symmetric model.
The full paper is available here:
arXiv
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The multi-epoch spectra of model DDC15 used to confront to SN 2002bo observations can
be downloaded here: SNIa_DDC15_model_B15.tgz (1.8M).
This also includes the input hydrodynamical model at 0.98 d past explosion.
The optical and NIR passbands used to compute UBVRIJHKs
magnitudes are available here:
optnir_passbands.tgz.