TY - JOUR
T1 - Optical and Infrared Spectroscopy of SN 1999ee and SN 1999ex
AU - Hamuy, Mario
AU - Maza, José
AU - Pinto, Philip A.
AU - Phillips, M. M.
AU - Suntzeff, Nicholas B.
AU - Blum, R. D.
AU - Olsen, K. A. G.
AU - Pinfield, David J.
AU - Ivanov, Valentin D.
AU - Augusteijn, T.
AU - Brillant, S.
AU - Chadid, M.
AU - Cuby, J. -G.
AU - Doublier, V.
AU - Hainaut, O. R.
AU - Le Floc'h, E.
AU - Lidman, C.
AU - Petr-Gotzens, Monika G.
AU - Pompei, E.
AU - Vanzi, L.
PY - 2002/7/1
Y1 - 2002/7/1
N2 - We report optical and infrared spectroscopic observations of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both of which were hosted by the galaxy IC 5179. For SN 1999ee we obtained a continuous sequence with an unprecedented wavelength and temporal coverage beginning 9 days before maximum light and extending through day 42. Before maximum light SN 1999ee displayed a normal spectrum with a strong Si II λ6355 absorption, thus showing that not all slow-declining supernovae (SNe) are spectroscopically peculiar at these evolutionary phases. A comparative study of the infrared spectra of SN 1999ee and other Type Ia SNe shows that there is a remarkable homogeneity among the Branch-normal SNe Ia during their first 60 days of evolution. SN 1991bg-like objects, on the other hand, display spectroscopic peculiarities at infrared wavelengths. SN 1999ex was characterized by the lack of hydrogen lines, weak optical He I lines, and strong He I λλ10830, 20581, thus providing an example of an intermediate case between pure Ib and Ic supernovae. We conclude, therefore, that SN 1999ex provides the first clear evidence for a link between the Ib and Ic classes and that there is a continuous spectroscopic sequence ranging from the He-deficient SNe Ic to the SNe Ib, which are characterized by strong optical He I lines. Based on observations collected at the European Southern Observatory, Chile (program ESO 164.H-0376).
AB - We report optical and infrared spectroscopic observations of the Type Ia SN 1999ee and the Type Ib/c SN 1999ex, both of which were hosted by the galaxy IC 5179. For SN 1999ee we obtained a continuous sequence with an unprecedented wavelength and temporal coverage beginning 9 days before maximum light and extending through day 42. Before maximum light SN 1999ee displayed a normal spectrum with a strong Si II λ6355 absorption, thus showing that not all slow-declining supernovae (SNe) are spectroscopically peculiar at these evolutionary phases. A comparative study of the infrared spectra of SN 1999ee and other Type Ia SNe shows that there is a remarkable homogeneity among the Branch-normal SNe Ia during their first 60 days of evolution. SN 1991bg-like objects, on the other hand, display spectroscopic peculiarities at infrared wavelengths. SN 1999ex was characterized by the lack of hydrogen lines, weak optical He I lines, and strong He I λλ10830, 20581, thus providing an example of an intermediate case between pure Ib and Ic supernovae. We conclude, therefore, that SN 1999ex provides the first clear evidence for a link between the Ib and Ic classes and that there is a continuous spectroscopic sequence ranging from the He-deficient SNe Ic to the SNe Ib, which are characterized by strong optical He I lines. Based on observations collected at the European Southern Observatory, Chile (program ESO 164.H-0376).
KW - supernovae: individual (1999ee)
KW - supernovae: individual (1999ex)
KW - Astrophysics
UR - https://www.scopus.com/pages/publications/0043244859
U2 - 10.1086/340968
DO - 10.1086/340968
M3 - Article
SN - 0004-6256
VL - 124
SP - 417
EP - 429
JO - Astronomical Journal
JF - Astronomical Journal
ER -