Details

Autor(en) / Beteiligte

• Garavini, G
• Folatelli, G
• Goobar, A
• Nobili, S
• Aldering, G
• Amadon, A
• Amanullah, R
• Astier, P
• Balland, C
• Blanc, G
• Burns, M. S
• Conley, A
• Dahlén, T
• Deustua, S. E
• Ellis, R
• Fabbro, S
• Fan, X
• Frye, B
• Gates, E. L
• Gibbons, R
• Goldhaber, G
• Goldman, B
• Groom, D. E
• Haissinski, J
• Hardin, D
• Hook, I. M
• Howell, D. A
• Kasen, D
• Kent, S
• Kim, A. G
• Knop, R. A
• Lee, B. C
• Lidman, C
• Mendez, J
• Miller, G. J
• Moniez, M
• Mourão, A
• Newberg, H
• Nugent, P. E
• Pain, R
• Perdereau, O
• Perlmutter, S
• Prasad, V
• Quimby, R
• Raux, J
• Regnault, N
• Rich, J
• Richards, G. T
• Ruiz-Lapuente, P
• Sainton, G
• Schaefer, B. E
• Schahmaneche, K
• Smith, E
• Spadafora, A. L
• Stanishev, V
• Walton, N. A
• Wang, L
• Wood-Vasey, W. M

Titel

Spectroscopic Observations and Analysis of the Peculiar SN 1999aa

Ist Teil von

• The Astronomical journal, 2004-07, Vol.128 (1), p.387-404

Ort / Verlag

IOP Publishing

Erscheinungsjahr

2004

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• We present an extensive new time series of spectroscopic data of the peculiar SN 1999aa in NGC 2595. Our data set includes 25 optical spectra between -11 and +58 days with respect to B-band maximum light, providing an unusually complete time history. The early spectra resemble those of an SN 1991T-like object but with a relatively strong Ca H and K absorption feature. The first clear sign of Si II lambda6355, characteristic of Type Ia supernovae, is found at day - 7, and its velocity remains constant up to at least the first month after B-band maximum light. The transition to normal-looking spectra is found to occur earlier than in SN 1991T, suggesting SN 1999aa as a possible link between SN 1991T - like and Branch-normal supernovae. Comparing the observations with synthetic spectra, doubly ionized Fe, Si, and Ni are identified at early epochs. These are characteristic of SN 1991T - like objects. Furthermore, in the day - 11 spectrum, evidence is found for an absorption feature that could be identified as high velocity C II lambda6580 or Halpha. At the same epoch C III lambda4648.8 at photospheric velocity is probably responsible for the absorption feature at 4500 Angstrom. High-velocity Ca is found around maximum light together with Si II and Fe II confined in a narrow velocity window. Implied constraints on supernovae progenitor systems and explosion hydrodynamic models are briefly discussed.