Walker, E. S. and Hachinger, S. and Mazzali, P. A. and Ellis, R. S. and Sullivan, M. and Gal-Yam, A. and Howell, D. A. (2012) Studying the diversity of Type Ia supernovae in the ultraviolet: comparing models with observations. Monthly Notices of the Royal Astronomical Society, 427 (1). pp. 103-113. ISSN 0035-8711. http://resolver.caltech.edu/CaltechAUTHORS:20130111-105225673
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In the ultraviolet (UV), Type Ia supernovae (SNe Ia) show a much larger diversity in their properties than in the optical. Using a stationary Monte Carlo radiative transfer code, a grid of spectra at maximum light was created varying bolometric luminosity and the amount of metals in the outer layers of the SN ejecta. This model grid is then compared to a sample of high-redshift SNe Ia in order to test whether the observed diversities can be explained by luminosity and metallicity changes alone. The dispersion in broad-band UV flux and colours at approximately constant optical spectrum can be readily matched by the model grid. In particular, the UV1 − b colour is found to be a good tracer of metal content of the outer ejecta, which may in turn reflect on the metallicity of the SN progenitor. The models are less successful in reproducing other observed trends, such as the wavelengths of key UV features, which are dominated by reverse fluorescence photons from the optical, or intermediate-band photometric indices. This can be explained in terms of the greater sensitivity of these detailed observables to modest changes in the relative abundances. Specifically, no single element is responsible for the observed trends. Due to their complex origin, these trends do not appear to be good indicators of either luminosity or metallicity.
|Additional Information:||© 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS. Accepted 2012 August 12. Received 2012 August 12; in original form 2012 June 4. Article first published online: 29 Oct. 2012. We acknowledge support from the Italian Space Agency (ASI) under contract ASI/INAF n. I/009/10/0 and I/016/07/0. ESW and SH are grateful for the hospitality of MPA, Garching and theWeizmann Institute of Science, Rehovot during stages of this work. Joint work by AG-Y and MS is supported by the Weizmann-UK ‘making connections’ programme. Joint work by AG-Y and PAM is supported by a Weizmann Minerva grant. AG-Y further acknowledges support from the ISF, an ARCHES award and the Lord Sieff of Brimpton fund.|
|Subject Keywords:||supernovae: general; cosmology: observations|
|Official Citation:||Walker, E. S., Hachinger, S., Mazzali, P. A., Ellis, R. S., Sullivan, M., Gal-Yam, A. and Howell, D. A. (2012), Studying the diversity of Type Ia supernovae in the ultraviolet: comparing models with observations. Monthly Notices of the Royal Astronomical Society, 427: 103–113. doi: 10.1111/j.1365-2966.2012.21928.x|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||12 Jan 2013 00:15|
|Last Modified:||12 Jan 2013 00:15|
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