Insight-HXMT insight into switch of the accretion mode: the case of the X-ray pulsar 4U 1901+03
Y. L. Tuo, L. Ji, S. S. Tsygankov, T. Mihara, L. M. Song, M. Y. Ge, A. Nabizadeh, L. Tao, J. L. Qu, Y. Zhang, S. Zhang, S. N. Zhang, Q. C. Bu, L. Chen, Y. P. Xu… 展开作者
Y. L. Tuo, L. Ji, S. S. Tsygankov, T. Mihara, L. M. Song, M. Y. Ge, A. Nabizadeh, L. Tao, J. L. Qu, Y. Zhang, S. Zhang, S. N. Zhang, Q. C. Bu, L. Chen, Y. P. Xu, X. L. Cao, Y. Chen, C. Z. Liu, C. Cai, Z. Chang, G. Chen, T. X. Chen, Y. B. Chen, Y. P. Chen, W. Cui, W. W. Cui, J. K. Deng, Y. W. Dong, Y. Y. Du, M. X. Fu, G. H. Gao, H. Gao, M. Gao, Y. D. Gu, J. Guan, C. C. Guo, D. W. Han, Y. Huang, J. Huo, S. M. Jia, L. H. Jiang, W. C. Jiang, J. Jin, Y. J. Jin, L. D. Kong, B. Li, C. K. Li, G. Li, M. S. Li, T. P. Li, W. Li, X. Li, X. B. Li, X. F. Li, Y. G. Li, Z. W. Li, X. H. Liang, J. Y. Liao, B. S. Liu, G. Q. Liu, H. W. Liu, X. J. Liu, Y. N. Liu, B. Lu, F. J. Lu, X. F. Lu, Q. Luo, T. Luo, X. Ma, B. Meng, Y. Nang, J. Y. Nie, G. Ou, N. Sai, R. C. Shang, X. Y. Song, L. Sun, Y. Tan, C. Wang, G. F. Wang, J. Wang, W. S. Wang, Y. S. Wang, X. Y. Wen, B. Y. Wu, B. B. Wu, M. Wu, G. C. Xiao, S. Xiao, S. L. Xiong, J. W. Yang, S. Yang, Y. J. Yang, Y. J. Yang, Q. B. Yi, Q. Q. Yin, Y. You, A. M. Zhang, C. M. Zhang, F. Zhang, H. M. Zhang, J. Zhang, T. Zhang, W. Zhang, W. C. Zhang, W. Z. Zhang, Y. Zhang, Y. F. Zhang, Y. J. Zhang, Y. H. Zhang, Y. Zhang, Z. Zhang, Z. Zhang, Z. L. Zhang, H. S. Zhao, X. F. Zhao, S. J. Zheng, Y. G. Zheng, D. K. Zhou, J. F. Zhou, Y. X. Zhu, Y. Zhu, R. L. Zhuang
We use the In data collected during the 2019 outburst from X-ray pulsar 4U 1901+03 to complement the orbital parameters reported by Fermi/GBM. Using the Insight-HXMT, we examine the correlation between the derivative of the intrinsic spin frequency and bolometric flux based on accretion torque models. It was found that the pulse profiles significantly evolve during the outburst. The existence of two types of the profile's pattern discovered in the Insight-HXMT data indicates that this source experienced transition between a super-critical and a sub-critical accretion regime during its 2019 outburst. Based on the evolution of the pulse profiles and the torque model, we derive the distance to 4U 1901+03 as 12.4+-0.2 kpc.
我们使用Insight-HXMT在发射后第一年的观测报告了蟹状星云脉冲星（PSR B 0531 +21）的X射线发射特性。我们在X射线能量带11-250 keV获得了高信噪比的配置文件。我们已经证实，随着能量的增加，第二峰与主峰的通量比增加，这与其他任务一致。随着能量的增加，两个峰的分离没有显示出显著的趋势。的相位平均光谱，拟合的logpar模型，和相位分辨光谱的蟹状星云脉冲星，拟合的幂律在不同的能带的HXMT，是一致的RXTE和NuSTAR的光子指数演变作为一个函数的相位，以及一个功能的能量有助于宽带建模。
The prolific thermonuclear X-ray bursts from the outburst of the newly discovered millisecond pulsar MAXI~J1816--195 observed by Insight-HXMT and NICER
We report results on the timing analysis of the 2020 giant outburst of 1A 0535+262, using broadband data from Insight-HXMT. The analysis of the pulse profile evolution from the sub-critical luminosity to super-critical luminosity regime is presented for the first time. We found that the observed pulse profile exhibits a complex dependence on both energy and luminosity.A dip structure at the energy of the cyclotron resonant scattering features (CRSFs) is found for the first time in the pulse fraction-energy relation of 1A 0535+262, when the outburst evolves in a luminosity range from 4.8 $\time…
We report on a detailed spectral analysis of emission from X-ray pulsar 4U 1901+03 using data obtained by the Insight-HXMT and NuSTAR observatories during the 2019 outburst of the source. Thanks to the extensive coverage of the outburst by Insight-HXMT, we were able to investigate the spectral evolution of the source as a function of flux, and compare these results to the previous reports, focusing on the properties of a putative absorption feature at around 10 keV. In particular, we demonstrate that the broadband X-ray continuum of 4U 1901+03 can be well described with a two-component continu…
We analyze the energy dependence of the X-ray pulse profile and the phase-resolved spectra (PRS) of the Crab pulsar using observations from the Neutron star Interior Composition Explorer (NICER) and the Hard X-ray Modulation Telescope (Insight-HXMT). We parameterize the pulse profiles and quantify the evolution of these parameters in the broad energy band of 0.4-250 keV. A log-parabola function is used to fit the PRS in 2-250 keV, and the curvature of the spectrum, i.e., the evolution of the photon index with energy, as represented by the parameter \{beta} of the log-parabola model, also chang…
The detection of cyclotron resonance scattering features (CRSFs) is the only way to directly and reliably measure the magnetic field near the surface of a neutron star (NS). The broad energy coverage and large collection area of \emph{Insight}-HXMT in the hard X-ray band allowed us to detect the CRSF with the highest energy known to date, reaching about 146 keV during the 2017 outburst of the first galactic pulsing ultraluminous X-ray source (pULX) Swift J0243.6+6124. During this outburst, the CRSF was only prominent close to the peak luminosity $\sim 2\times10^{39}$ erg s$^{-1}$, the highest …
We report the orbital X-ray variability of high mass X-ray binary (HMXB) GX301--2. GX301--2 undergone a spin up process in 2018--2020 with the period evolving from $\sim$ 685 s to 670 s. The energy resolved pulse-profiles of the pulsar in 1--60 keV varied from single peaked and sinusoidal shapes to multi-peaked across different orbital phases. Pulse fractions evolving over orbit had negative correlations with the X-ray flux. The broad-band X-ray energy spectrum of the pulsar can be described with a partial covering negative positive cutoff power-law continuum model. Near the periastron passage…
We investigate the absorption and emission features in observations of GX 301-2 detected with Insight-HXMT/LE in 2017-2019. At different orbital phases, we found prominent Fe Kalpha, Kbeta and Ni Kalpha lines, as well as Compton shoulders and Fe K-shell absorption edges. These features are due to the X-ray reprocessing caused by the interaction between the radiation from the source and surrounding accretion material. According to the ratio of iron lines Kalpha and Kbeta, we infer the accretion material is in a low ionisation state. We find an orbital-dependent local absorption column density, …
We have performed phase-resolved spectral analysis of the accreting pulsar 1A~0535+262 based on observations of Insight-HXMT during the 2020 Type-II outburst of the source. We focus on the two-dimensional dependence of the cyclotron resonance scattering features (CRSFs) along the outburst time and at different phases. The fundamental CRSF line (f-CRSF) shows different time- and phase-dependent behaviors. At higher luminosity, the phase profile of the f-CRSF energy changes from a single peak to double peaks, with the transition occurring at MJD 59185. On the contrary, the first harmonic CRSF (1…
We report on the observation of the accreting pulsar GRO J1008-57 performed by Insight-HXMT at the peak of the source's 2017 outburst. Pulsations are detected with a spin period of 93.283(1) s. The pulse profile shows double peaks at soft X-rays, and only one peak above 20 keV. The spectrum is well described by the phenomenological models of X-ray pulsars. A cyclotron resonant scattering feature is detected with very high statistical significance at a centroid energy of $E_{\rm cyc}=90.32_{-0.28}^{+0.32}$ keV, for the reference continuum and line models, HIGHECUT and GABS respectively. Detecti…
We report on a detailed spectral analysis of the transient X-ray pulsar 1A~0535+262, which underwent the brightest giant outburst ever recorded for this source from November to December 2020 with a peak luminosity of $1.2$ $\times10^{38}\ \rm erg\ s^{-1}$. Thanks to the unprecedented energy coverage and high cadence observations provided by Insight-HXMT, we were able to find for the first time evidence for a transition of the accretion regime. At high luminosity, above the critical luminosity $6.7\times10^{37}$ erg s$^{-1}$, the cyclotron absorption line energy anti-correlates with luminosity.…
Statistical properties of type-II bursts in Rapid Burster observed with Insight-HXMT
School of Physics and Astronomy, Sun Yat-Sen University（中山大学物理学院）；CSST Science Center for the Guangdong-Hong Kong-Macau Greater Bay Area（中国空间站科学中心粤港澳大湾区分中心）
Cyclotron line scattering features are detected in a few tens of X-ray pulsars (XRPs) and used as direct indicators of a strong magnetic field at the surface of accreting neutron stars (NSs). In a few cases, cyclotron lines are known to be variable with accretion luminosity of XRPs. It is accepted that the observed variations of cyclotron line scattering features are related to variations of geometry and dynamics of accretion flow above the magnetic poles of a NS. A positive correlation between the line centroid energy and luminosity is typical for sub-critical XRPs, where the accretion result…
The accreting millisecond X-ray pulsar Swift J1756.9$-$2508 went into outburst in April 2018 and June 2019, 8.7 yr after the previous activity period. We investigated the temporal, timing and spectral properties of these two outbursts using data from NICER, XMM-Newton, NuSTAR, INTEGRAL, Swift and Insight-HXMT. The two outbursts exhibited similar broad-band spectra and X-ray pulse profiles. For the first time, we report the detection of the pulsed emission up to $\sim100$ keV observed by Insight-HXMT during the 2018 outburst. We also found the pulsation up to $\sim60$ keV observed by NICER and …
Synchronous X-ray and Radio Mode Switches: a Rapid Global Transformation of the Pulsar Magnetosphere
脉冲星发射低频无线电波，直到高能伽马射线，这些伽马射线产生于从表面到磁层边缘的任何地方。因此，检测多波长发射中的相关模式变化是理解这些发射位点之间的物理关系的关键。通过同步观测，我们探测到PSR B 0943 +10的射电和X射线发射特性的同步开关。当脉冲星处于持续的无线电“明亮”模式时，X射线只显示非脉冲，非热成分。相反，当脉冲星处于无线电“安静”模式时，X射线亮度增加一倍以上，并且观察到100%的脉冲热分量以及非热分量。这表明磁层的条件发生了快速的全球性变化，这对所有提出的脉冲星发射理论提出了挑战。
We investigated the quasi-periodic oscillation (QPO) features in the accretion-powered X-ray pulsar Cen X-3 observed by Insight-HXMT. For two observations in 2020 when Cen X-3 was in an extremely soft state, the power density spectrum revealed the presence of obvious QPO features at $\sim$40 mHz with an averaged fractional rms amplitude of $\sim9\%$. We study the mHz QPO frequency and rms amplitude over orbital phases, and find that the QPO frequency is $\sim$33-39 mHz at the orbital phase of 0.1-0.4, increasing to $\sim$37-43 mHz in the orbital phase of 0.4-0.8, but has no strong dependence o…
We report on a detailed study of the mode switching in pulsar J1326$-$6700 by analyzing the data acquired from the Parkes 64 m radio telescope at 1369 MHz. During the abnormal mode, the emission at the central and trailing components becomes extremely weak. Meanwhile, the leading emission shifts toward earlier longitude by almost 2°, and remains in this position for typically less than a minute. The mean flux density of the normal mode is almost five times that of the abnormal mode. Our data show that, for PSR J1326$-$6700, 85% of the time was spent in the normal mode and 15% was in the abnorm…
The radio and X-ray mode-switching pulsar PSR B0943+10
过去几年中获得的观测结果挑战了普遍存在的观点，即旋转动力中子星是稳定的X射线发射体。除了少数据称具有旋转动力的中子星表现出“类磁星”的变化外，PSR B 0943 +10是一个特别有趣的例子。最近的观测表明，这颗脉冲星在无线电波段进行了很好的研究，它在明亮和静止模式之间交替，显示出显着的X射线变化，与无线电发射的通量密切相关。这种同步射电/X射线模式转换的研究为研究脉冲星射电和高能辐射过程打开了一扇新的窗口。本文综述了PSR B 0943 +10的主要X射线性质，这些性质是由最近的X射线和射电观测数据得到的。
We report on pulse profile decomposition analysis of a bright transient X-ray pulsar 1A 0535+262 using the broadband Insight-HXMT observations during a giant outburst of the source in 2020. We show that the observed pulse profile shape can be described in terms of a combination of two symmetric single-pole contributions for wide range of energies and luminosities for a fixed geometry defining basic geometry of the pulsar. This corresponds to a slightly distorted dipole magnetic field, i.e., one pole has to be offset by $\sim 12^{\circ}$ from the antipodal position of the other pole. We reconst…
We describe the timing system and the timing calibration results of the three payloads on-board the Insight-Hard X-ray Modulation Telescope (Insight-HXMT). These three payloads are the High Energy X-ray telescope (HE, 20-250 keV), the Medium Energy X-ray telescope (ME, 5-30 keV) and the low Energy X-ray telescope (LE, 1-10 keV). We present a method to correct the temperature-dependent period response and the long-term variation of the on-board crystal oscillator, especially for ME that does not carry a temperature-compensated crystal oscillator. The time of arrivals (ToAs) of the Crab pulsar a…
GX 301-2 provides a rare opportunity to study both disk and wind accretion in a same target. We report Insight-HXMT observations of the spin-up event of GX 301-2 happened in 2019 and compare with those of wind-fed state. The pulse profiles of the initial rapid spin-up period are dominated by one main peak, while those of the later slow spin-up period are composed of two similar peaks, as those of wind-fed state. These behaviors are confirmed by Fermi/GBM data, which also show that during the rapid spin-up period, the main peak increases with luminosity up to $8\times10^{37}$ erg s$^{-1}$, but …
We present a detailed timing study of the pulse profile of Swift J0243.6+6124 with HXMT and Fermi/GBM data during its 2017 giant outburst. The double-peak profile at luminosity above $5\times10^{38}$erg\,s$^{-1}$ is found to be 0.25 phase offset from that below $1.5\times10^{38}$erg\,s$^{-1}$, which strongly supports for a transition from a pencil beam to a fan beam, and thus for the formation of shock dominated accretion column. During the rising stage of the high double-peak regime, the faint peak got saturated in 10-100 keV band above a luminosity of $L_t\sim1.3\times10^{39}$erg\,s$^{-1}$, …
The Pulsar backend of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) has monitored hundreds of known pulsars in the northern sky since Fall 2018, providing a rich data set for the study of temporal variations in pulsar emission. Using a matched filtering technique, we report, for the first time, nulling behaviour in five pulsars as well as mode switching in nine pulsars. Only one of the pulsars is observed to show both nulling and moding signals. These new nulling and mode switching pulsars appear to come from a population with relatively long spin periods, in agreement with previo…
We present detailed timing and spectral analyses of the transient X-ray pulsar RX J0209.6$-$7427 in the Small Magellanic Cloud during its 2019 giant outburst. With a better known distance than most galactic X-ray pulsars, its peak luminosity is determined to be $(1.11\pm0.06)\times 10^{39}\, \rm erg\ s^{-1}$; it is thus a {\it bonda fide} pulsating ultraluminous X-ray source (PULX). Owing to the broad energy band of \textit{Insight}-HXMT, its pulsed X-ray emission was detected from 1 keV up to the 130$-$180 keV band, which is the highest energy emission detected from any PULXs outside the Milk…
GRO J1008-57, as a Be/X-ray transient pulsar, is considered to have the highest magnetic field in known neutron star X-ray binary systems. Observational data of the X-ray outbursts in GRO J1008-57 from 2017 to 2020 were collected by the Insight-HXMT satellite. In this work, the spin period of the neutron star in GRO J1008-57 was determined to be about 93.28 seconds in August 2017, 93.22 seconds in February 2018, 93.25 seconds in June 2019 and 93.14 seconds in June 2020. GRO J1008-57 evolved in the spin-up process with a mean rate of $-(2.10\pm 0.05)\times$10$^{-4}$ s/d from 2009 -- 2018, and t…
2014年11月，利用XMM-牛顿和LOFAR、LWA和Arecibo射电望远镜对原型模式转换脉冲星PSR B 0943 +10进行了新的同步X射线和射电观测。它们使我们能够更好地约束这颗脉冲星的X射线光谱和变化特性，并首次在X射线较暗模式下探测到X射线脉动。结合的时间和频谱分析表明，非脉冲非热发射，可能的磁层起源，脉冲热发射从一个小极冠存在于两个无线电模式，并在相关的方式变化。
LOFAR observations of the mode-switching pulsar B0943+10
PSR B0943+10是一颗旧的非回收脉冲星，几十年来以其快速和自发的无线电模式切换而闻名。最近，Hermsen等人（2013年）发现了极盖热X射线发射的相关变化，从而证明无线电模式不仅仅是无线电发射区域局部变化的产物，而是某些全球磁层转变的标志。大约在同一时间，由于新一代低频无线电阵列投入使用，可以在电离层透明度窗口的最低边缘进行宽带观测。在这些射频下，PSR B0943+10发射的轮廓形态和单脉冲特性变得非常动态，不仅提供了关于发射本身的细节，而且还提供了关于极隙条件的细节。在这里，我将介绍PSR B0943+10的LOFAR观测的最新结果，并讨论它们对多波长图像的贡献。
