arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1102.1455astro-ph.HE
收藏

关于热核X射线爆发的冷却尾:IGR J17480-2446链路

On the cooling tails of thermonuclear X-ray bursts: the IGR J17480-2446 link

M. Linares, D. Chakrabarty, M. van der Klis

摘要:

最近在球状星团Terzan 5中发现的中子星瞬变和11 Hz X射线脉冲星IGR J17480-2446在2010年11月爆发期间显示出前所未有的爆发活动。我们分析了罗西X射线计时探测器探测到的所有X射线爆发,并发现了强有力的证据,表明它们都有一个热核起源,尽管事实上,许多没有显示出典型的光谱软化沿衰变的印记上的I型X射线爆发的冷却的中子星光球。我们发现,持续爆发的功率比是完全一致的吸积的热核效率比沿整个爆发,是典型的I型X射线爆发。爆发能量、峰值亮度和日平均光谱轮廓在整个爆发过程中都与持续(非爆发)亮度平行地平稳演变。我们还发现,峰值爆发持续亮度比决定是否冷却存在于IGR J17480-2446的爆发,并认为,明显缺乏冷却是由于“非冷却”的爆发具有较低的峰值温度和较高的非爆发(持续)发射。我们的结论是,沿衰变冷却的检测是一个充分的,但不是必要的条件,以确定一个X射线爆发热核。最后,我们将这些发现与其他快速吸积的中子星的X射线爆发进行了比较。

英文摘要:

The neutron star transient and 11 Hz X-ray pulsar IGR J17480-2446, recently discovered in the globular cluster Terzan 5, showed unprecedented bursting activity during its 2010 October-November outburst. We analyzed all X-ray bursts detected with the Rossi X-ray Timing Explorer and find strong evidence that they all have a thermonuclear origin, despite the fact that many do not show the canonical spectral softening along the decay imprinted on type I X-ray bursts by the cooling of the neutron star photosphere. We show that the persistent-to-burst power ratio is fully consistent with the accretion-to-thermonuclear efficiency ratio along the whole outburst, as is typical for type I X-ray bursts. The burst energy, peak luminosity and daily-averaged spectral profiles all evolve smoothly throughout the outburst, in parallel with the persistent (non-burst) luminosity. We also find that the peak burst to persistent luminosity ratio determines whether or not cooling is present in the bursts from IGR J17480-2446, and argue that the apparent lack of cooling is due to the "non-cooling" bursts having both a lower peak temperature and a higher non-burst (persistent) emission. We conclude that the detection of cooling along the decay is a sufficient, but not a necessary condition to identify an X-ray burst as thermonuclear. Finally, we compare these findings with X-ray bursts from other rapidly accreting neutron stars.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑