Journal article
Spectroscopic Observations and Analysis of the Peculiar SN 1999aa
The Astronomical journal, v 128(1), pp 387-404
01 Jul 2004
Abstract
We present an extensive new time series of spectroscopic data of the peculiar SN 1999aa in NGC 2595. Ourdata set includes 25 optical spectra between 11 and +58 days with respect to B-band maximum light, providingan unusually complete time history. The early spectra resemble those of an SN 1991T–like object but with arelatively strong Ca H and K absorption feature. The first clear sign of Si ii k6355, characteristic of Type Iasupernovae, is found at day 7, and its velocity remains constant up to at least the first month after B-bandmaximum light. The transition to normal-looking spectra is found to occur earlier than in SN 1991T, suggestingSN 1999aa as a possible link between SN 1991T–like and Branch-normal supernovae. Comparing the observationswith synthetic spectra, doubly ionized Fe, Si, and Ni are identified at early epochs. These are characteristicof SN 1991T–like objects. Furthermore, in the day 11 spectrum, evidence is found for an absorptionfeature that could be identified as high velocity C ii k6580 or H. At the same epoch C iii k4648.8 at photosphericvelocity is probably responsible for the absorption feature at 4500 8. High-velocity Ca is found aroundmaximum light together with Si ii and Fe ii confined in a narrow velocity window. Implied constraints onsupernovae progenitor systems and explosion hydrodynamic models are briefly discussed.
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Details
- Title
- Spectroscopic Observations and Analysis of the Peculiar SN 1999aa
- Creators
- G GaraviniGastón Folatelli - FysikumAriel Goobar - Kosmologi Partikelastrofysik och SträngteoriSerena Nobili - Kosmologi Partikelastrofysik och Strängteoriet alSupernova Cosmology ProjectGordon T Richards - Physics
- Publication Details
- The Astronomical journal, v 128(1), pp 387-404
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Physics
- Web of Science ID
- WOS:000222702800031
- Scopus ID
- 2-s2.0-4544291816
- Other Identifier
- 991021869042104721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Astronomy & Astrophysics