{"paper":{"title":"Time-Varying Sodium Absorption in the Type Ia Supernova 2013gh","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA","astro-ph.HE"],"primary_cat":"astro-ph.SR","authors_text":"A. Goobar, A. V. Filippenko, D. A. Howell, E. Freeland, G. Doran, G. Hosseinzadeh, J. Johansson, J. Nordin, P. E. Nugent, P. Lundqvist, P. M. Vreeswijk, P. Wozniak, R. Amanullah, R. Ferretti, R. P. Butler, S. B. Cenko, S. Mattila, S. Valenti, S. Vogt, T. Petrushevska, Y. Cao","submitted_at":"2016-05-05T20:00:47Z","abstract_excerpt":"Temporal variability of narrow absorption lines in high-resolution spectra of Type Ia supernovae (SNe Ia) is studied to search for circumstellar matter. Time series which resolve the profiles of absorption lines such as Na I D or Ca II H&K are expected to reveal variations due to photoionisation and subsequent recombination of the gases. The presence, composition, and geometry of circumstellar matter may hint at the elusive progenitor system of SNe Ia and could also affect the observed reddening law. To date, there are few known cases of time-varying Na I D absorption in SNe Ia, all of which o"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1605.01738","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}