The Properties of Supernova 1997cy Associated with GRB 970514
The Properties of Supernova 1997cy Associated with GRB 970514
复制标题
DOI：
10.1086/312653
复制
发表时间：
1999-10
期刊：
影响因子：
--
通讯作者：
M. Turatto;T. Suzuki;P. Mazzali;S. Benetti;E. Cappellaro;I. J. Danziger;K. Nomoto;T. Nakamura
中科院分区：
文献类型：
--
作者：
M. Turatto;T. Suzuki;P. Mazzali;S. Benetti;E. Cappellaro;I. J. Danziger;K. Nomoto;T. Nakamura
近两年来，人们用光度和光谱方法观测到了与伽玛暴970514有关的超常SN1997Cy。在发现时，SN1997cy是迄今观测到的最亮的超新星(MV≤-20.1，VHEL=19,140公里S-1，H0=65公里S-1Mpc-1)。直到最后一次可用观测(伽马射线暴后600天)，总的时间积分通量等于或大于由2.3Mγ产生的☉射线完全热化所产生的通量。然而，从第60天开始，光度下降的速度慢于56Co的衰变速度，这表明锡喷出物与星周物质(CSM)相互作用。这种相互作用似乎在第550天左右减弱。SN1997Cy的光谱在所有历元都以Hα发射为主，它至少显示了三个不同宽度的成分，如SN1988Z。也可以看到其他几条不同宽度的线条，特别是在早期时期。一颗大质量恒星(25M☉)的高能(E=3×1052ergs)抛射物与CSM相互作用的模型再现了SN1997cy的整个光曲线，其中有一些来自放射性衰变的贡献。CSM可能是在爆炸前104年从蓝色恒星演化为红色超巨星时以≈4×10-4M☉yr-1的质量损失率被抛出的。星云相的光谱中缺乏氧气和镁线，这对需要高质量前体的模型构成了一个问题。讨论了母体的大部分核心物质落在一个大质量黑洞上，从而使反向激波在H/He包层内缘消亡的可能性。
The extraordinary SN 1997cy associated with GRB 970514 has been observed photometrically and spectroscopically for nearly 2 yr. At the time of discovery, SN 1997cy was the brightest supernova (SN) ever observed (MV ≤ -20.1, vhel = 19,140 km s-1, H0 = 65 km s-1 Mpc-1). Up to the last available observations (600 days after the gamma-ray burst), the total time-integrated flux was equal to or larger than that expected from the complete thermalization of the γ-rays produced by 2.3 M☉ of 56Co. However, starting already on day 60 the luminosity decline is slower than the 56Co decay rate, indicating that the SN ejecta was interacting with circumstellar material (CSM). The interaction appeared to weaken around day 550. The spectra of SN 1997cy are dominated at all epochs by Hα emission, which shows at least three components of different widths, as in SN 1988Z. Several other lines with different widths are also visible, especially at early epochs. The entire light curve of SN 1997cy is reproduced by a model of the interaction of the very energetic (E = 3 × 1052 ergs) ejecta of a massive star (25 M☉) with the CSM, with some contribution from radioactive decays. The CSM could have been ejected with a mass-loss rate of ≈ 4 × 10-4 M☉ yr-1 as the progenitor star evolved from a blue to a red supergiant about 104 yr before the explosion. The lack of oxygen and magnesium lines in the spectra at nebular phases poses a problem for models requiring high-mass progenitors. The possibility that most of the core material of the progenitor has fallen onto a massive black hole so that the reverse shock dies at the inner edge of the H/He envelope is discussed.