Gamma-ray emission from individual classical novae
Gamma-ray emission from individual classical novae
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DOI：
10.1046/j.1365-8711.1998.01421.x
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发表时间：
1998-06-01
影响因子：
4.8
通讯作者：
Isern, J
中科院分区：
文献类型：
--
作者：
Gomez-Gomar, J;Hernanz, M;Isern, J
经典新星是放射性核的重要产生者，例如(7)Be、(13)N、(18)F、(22)Na和(26)Al。这些原子核的衰变产生正电子（(7)Be 除外），正电子通过电子湮灭产生能量为 511 keV 及以下的光子。此外，(7)Be 和 (22)Na 衰变产生的光子能量分别为 478 keV 和 1275 keV，均位于伽马射线域。因此，新星是伽马射线发射的潜在来源。我们开发了两种代码，以便仔细分析单个经典新星的伽马射线发射：一种是流体动力学代码，它遵循吸积和爆炸阶段；另一种是蒙特卡罗代码，能够处理伽马射线光子的产生和转移。两个代码已结合起来以模拟真实的爆炸。分析了伽马射线光谱和伽马射线光曲线（连续谱和 511、478 和 1275 keV 线）的特性，特别强调碳-氧新星和氧-氖新星之间的差异。通过未来 INTEGRAL 卫星上的 SPI 光谱仪对单个新星的可探测性进行了预测。对于 (26)Al，它的衰变产生 1809 keV 的光子，但这发生的时间尺度比银河系中新星爆发之间的典型时间间隔长得多，因此在单个新星中无法检测到。本文尚未对许多银河新星的 (26)Al 累积发射进行建模。
Classical novae are important producers of radioactive nuclei, such as (7)Be, (13)N, (18)F, (22)Na and (26)Al. The disintegration of these nuclei produces positrons (except for (7)Be) that through annihilation with electrons produce photons of energies 511 keV and below. Furthermore, (7)Be and (22)Na decay producing photons with energies of 478 and 1275 keV, respectively, well in the gamma-ray domain. Therefore, novae are potential sources of gamma-ray emission. We have developed two codes in order to analyse carefully the gamma-ray emission of individual classical novae: a hydrodynamical one, which follows both the accretion and the explosion stages, and a Monte Carlo one, able to treat both production and transfer of gamma-ray photons. Both codes have been coupled in order to simulate realistic explosions. The properties of gamma-ray spectra and gamma-ray light curves (for the continuum and for the lines at 511, 478 and 1275 keV) have been analysed, with a special emphasis on the difference between carbon-oxygen and oxygen-neon novae. Predictions of detectability of individual novae by the future SPI spectrometer on board the INTEGRAL satellite are made. Concerning (26)Al, its decay produces photons of 1809 keV but this occurs on a time-scale much longer than the typical time interval between nova outbursts in the Galaxy, making it undetectable in individual novae. The accumulated emission of (26)Al from many Galactic novae has not been modelled in this paper.