Other
Scientific paper
May 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001aas...198.3902h&link_type=abstract
American Astronomical Society, 198th AAS Meeting, #39.02; Bulletin of the American Astronomical Society, Vol. 33, p.838
Other
20
Scientific paper
SN 1999as was discovered on February 18, 1999 during the LBNL 1999 nearby supernova campaign, in an anonymous galaxy having a redshift of 0.127. The absolute magnitude was exceptionally bright, at least -21.4 --- at least nine time brighter than the hypernova SN 1998bw, which apparently was associated with a gamma--ray burst. The light curve and the photospheric velocities have been computed with a one-dimensional spherically symmetric radiative transfer code. From fitting the observed light curve, we have obtained the following constraints on the explosion model: the ejected mass M ej { ~} 10 - 20 Msun, the kinetic energy of ejected matter E K { ~} 1052 - 1053 ergs, and the mass of ejected radioactive nickel MNi > 4 Msun. SN 1999as is spectroscopically classified as a type Ic supernova because its photospheric phase spectra show no conspicuous lines of hydrogen, He I, or Si II λ 6355. However, in addition to the usual supernova SN Ic spectral lines such as Ca II and O I, some narrow ( ~ 2000 km s-1) but highly blueshifted ( ~ 11,000 km s-1) lines of Fe II are present. We present the results of a direct spectroscopic analysis using the parameterized supernova spectrum synthesis code, SYNOW, as well as a comparison with other type Ic hypernovae, SNe 1997ef and 1998bw. We suggest that the 2--dimensional asymmetric hydrodynamical model of Maeda et al. (astro-ph/0011003) could represent this new class of hypernova. In the Maeda model, a clump of freshly synthesized 56Ni exists at high velocity ( ~ 15,000 km s-1) near the symmetry axis; such a clump could produce narrow but high--velocity absorption lines if the viewing angle with respect to the symmetry axis is small. All of the observed spectroscopic and light curve data were obtained during the LBNL 1999 nearby supernova campaign.
Aldering Greg
Branch David
Deng Jin-Song
Hatano Kazuhito
Maeda Kengo
No associations
LandOfFree
The Type Ic Hypernova SN 1999as does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Type Ic Hypernova SN 1999as, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Type Ic Hypernova SN 1999as will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1269061