Time dependence of the flux of helium nuclei in cosmic rays measured by the PAMELA experiment between July 2006 and December 2009
N. Marcelli, M. Boezio, A. Lenni, W. Menn, R. Munini, O. P. M. Aslam, D. Bisschoff, M. D. Ngobeni, M. S. Potgieter, O. Adriani, G. C. Barbarino, G. A. Bazilevsk… 展开作者
N. Marcelli, M. Boezio, A. Lenni, W. Menn, R. Munini, O. P. M. Aslam, D. Bisschoff, M. D. Ngobeni, M. S. Potgieter, O. Adriani, G. C. Barbarino, G. A. Bazilevskaya, R. Bellotti, E. A. Bogomolov, M. Bongi, V. Bonvicini, A. Bruno, F. Cafagna, D. Campana, P. Carlson, M. Casolino, G. Castellini, C. De Santis, A. M. Galper, S. V. Koldashov, S. Koldobskiy, A. N. Kvashnin, A. A. Leonov, V. V. Malakhov, L. Marcelli, M. Martucci, A. G. Mayorov, M. Mergè, E. Mocchiutti, A. Monaco, N. Mori, V. V. Mikhailov, G. Osteria, B. Panico, P. Papini, M. Pearce, P. Picozza, M. Ricci, S. B. Ricciarini, M. Simon, A. Sotgiu, R. Sparvoli, P. Spillantini, Y. I. Stozhkov, A. Vacchi, E. Vannuccini, G. I. Vasilyev, S. A. Voronov, Y. T. Yurkin, G. Zampa, N. Zampa
Precise time-dependent measurements of the Z = 2 component in the cosmic radiation provide crucial information about the propagation of charged particles through the heliosphere. The PAMELA experiment, with its long flight duration (15th June 2006 - 23rd January 2016) and the low energy threshold (80 MeV/n) is an ideal detector for cosmic ray solar modulation studies. In this paper, the helium nuclei spectra measured by the PAMELA instrument from July 2006 to December 2009 over a Carrington rotation time basis are presented. A state-of-the-art three-dimensional model for cosmic-ray propagation inside the heliosphere was used to interpret the time-dependent measured fluxes. Proton-to-helium flux ratio time profiles at various rigidities are also presented in order to study any features which could result from the different masses and local interstellar spectra shapes.
Two new outbursts and transient hard X-rays from 1E 1048.1$-$5937
自发现以来，1 E 1048.1 $-$ 5937一直是最活跃的磁星之一，无论是在辐射爆发方面，还是在自旋性质的变化方面。在这里，我们报告了尼尔·盖尔斯斯威夫特天文台X射线望远镜的持续监测活动，其中我们观察到该来源的两次新爆发。第一次爆发发生在2016年7月，第二次爆发发生在2017年12月，分别达到$3.2^{+0.2}_{-0.3}\times 10^{-11}$ erg s $^{-1}$ cm $^{-2}$和$2.2^{+0.2}_{-0.2}\times10^{-11}$ erg s $^{-1}$ cm $^{-2}$的0.5-10 keV吸收通量峰值，$\sim$ 5和$\sim 4$因子高于静态通量。这两个新的爆发都伴随着自旋上升毛刺，幅度分别为$Δν= 4.47(6)\times10^{-7}$ Hz和$Δν= 4.32(5)\times10^{-7}$ Hz。在2016年7月爆发之后，我们观察到，与过去的爆发一样，延迟扭矩波动的一段时间，其达到$1.73\pm0.01$乘以静止速率的峰值自旋下降，并且与自旋上升故障相比，其主导了自旋演化。我们还报告了一个观察的峰值附近的第一个这些爆发与NuSTAR的硬X射线发射被检测到从源。这种发射的特点是吸收的黑体加上一个破幂律，与幂律指数以上的$13.4\pm0.6$千电子伏的$0.5_{-0.2}^{+0.3}$，类似于…
