论文标题
SAX J1712.6-3739中的高能热核突发
The energetic thermonuclear bursts in SAX J1712.6-3739
论文作者
论文摘要
中子恒星低质量X射线二进制SAX J1712.6-3739在过去的X射线观察中以其非常长而坚硬的热核突发而闻名。它的热核爆发是如此的活力，以至于在Swift/BAT（E> 15 KEV）的硬X射线观察中，它们甚至可以持续数十分钟。为了探索SAX J1712.6-3739及其热核爆发的本质，我们分析了其四次爆发，这些突发都被Swift/Bat捕获。通过应用Swift/BAT和Swift/XRT的档案观察数据来得出这些爆发的峰值通量和通量。基于Swift观察到的峰值通量，SAX J1712.6-3739的距离估计为4.6 kpc，比Bepposax观测值比估计值近得多。相应的绝对幅度和平均积聚率同意其超紧凑型X射线二元性质。通过测量有效持续时间，我们确定2010年的爆发对应于正常的X射线爆发，2011年的爆发与中间持续爆发一致，而2014年和2018年爆发比普通的中间冲突爆发更富集，但比超级爆炸较少，但比超级爆炸较少。由于SAX J1712.6-3739的平均质量积聚率仅为0.6％的Eddington增生率，而当前的理论预测，在非常低的吸积率下，毛毛的产量没有碳的产量。因此，2014年和2018年爆发很可能是深氦爆发。在迅速的观察结果中，SAX J1712.6-3739在热核突发中至少显示了三种不同水平的持续时间。它们可能是由可变的积聚率引起的，因为它们的点火柱深度大致遵循以相应的吸积速率预测纯氦爆发的点火模型。
The neutron star low-mass X-ray binary SAX J1712.6-3739 is known for its very long and hard thermonuclear bursts in past X-ray observations. Its thermonuclear bursts are so energetic that they can even last for tens of minutes in the hard X-ray observations of Swift/BAT (E > 15 keV). For exploring the natures of SAX J1712.6-3739 and its thermonuclear bursts, we analyzed its four bursts which were all captured by Swift/BAT. The peak flux and fluence for these bursts are derived by applying the archive observation data of Swift/BAT and Swift/XRT. Based on the peak fluxes observed by Swift, the distance of SAX J1712.6-3739 is estimated as 4.6 kpc, which is much closer than the estimate by the BeppoSAX observations. The corresponding absolute magnitude and average accretion rate agree its ultra-compact X-ray binary nature. By the measurements of effective duration, we determined that the 2010 burst corresponds to a normal X-ray burst, the 2011 burst is consistent with an intermediate-duration burst while the 2014 and the 2018 bursts are more energetic than common intermediate-duration bursts but less energetic than superbursts. Since the average mass accretion rate of SAX J1712.6-3739 was only 0.6% Eddington accretion rate, and current theory predict no carbon production in the bursters under very low accretion rate. Therefore, the 2014 and the 2018 bursts are very likely to be deep helium bursts. In the Swift observations, SAX J1712.6-3739 has shown at least three different levels of duration in thermonuclear bursts. They were possibly induced by variable accretion rates, because their ignition column depths roughly follow the prediction of ignition models for pure helium bursts at corresponding accretion rates.
