Recently, the magnetar Swift J1834.9$-$0846 is reported to have a possible wind nebula. It is shown that both the magnetar and its wind nebula are understandable in the wind braking scenario. The magnetar's rotational energy loss rate is not enough to power the particle luminosity. The required particle luminosity should be about $10^{36} \,\rm erg \,s^{-1}$ to $10^{38} \,\rm erg \,s^{-1}$. It is obtained in three different approaches: considering wind braking of Swift J1834.9$-$0846; the spectral and spatial observations of the wind nebula; and an empirical upper bound on wind nebula X-ray luminosity. The nebula magnetic field is about $10^{-4} \,\rm G$. The possible wind nebula of Swift J1834.9$-$0846 should be a magnetar wind nebula. It is powered by the magnetic energy release of the magnetar.
Boasting supreme magnetic strengths, magnetars are among the prime candidates to generate fast radio bursts. Several theories have been proposed for the formation mechanism of magnetars, but have not yet been fully tested. As different magnetar formation theories expect distinct magnetar space velocity distributions, high-precision astrometry of Galactic magnetars can serve as a probe for the formation theories. In addition, magnetar astrometry can refine the understanding of the distribution of Galactic magnetars. This distribution can be compared against fast radio bursts (FRBs) localized in…
Swift J1818.0-1607 is a new radio-loud magnetar discovered by the Swift Burst Alert Telescope on 2020 March 12. It has a magnetic field B~2.5e14 G, spin-down luminosity of 7.2e35 ergs/s, and characteristic age of ~470yr. Here we report on the Chandra observations of Swift J1818.0-1607, which allowed for a high-resolution imaging and spectroscopic study of the magnetar and its environment. The 1-10 keV spectrum of the magnetar is best described by a single blackbody model with a temperature of 1.2\pm0.1 keV and an unabsorbed flux of 1.9e-11 ergs/cm^2/s. This implies an X-ray luminosity of ~9.6e…
Swift J1818.0-1607 discovered in early 2020 is not only the fifth magnetar known with periodic radio pulsations but also the fastest rotating one. Simultaneous 2.25 and 8.60 GHz observations of Swift J1818.0-1607 were carried out with Shanghai Tian Ma Radio Telescope (TMRT) from MJD 58936 to 59092. The spin-frequency $ν$ and first-order derivative $\dotν$ of this magnetar were obtained with piecewise fitting method because of its instable timing properties. We found that the amplitude of short-term $\dotν$ fluctuations decreased with time, and the long-term declining trend of $ν$ discovered pr…
The soft-gamma repeater Swift J1818.0$-$1607 is only the fifth magnetar found to exhibit pulsed radio emission. Using the Ultra-Wideband Low receiver system of the Parkes radio telescope, we conducted a 3 h observation of Swift J1818.0$-$1607. Folding the data at a rotation period of $P = 1.363$ s, we obtained wideband polarization profiles and flux density measurements covering radio frequencies between 704-4032 MHz. After measuring, and then correcting for the pulsar's rotation measure of $1442.0 \pm 0.2$ rad m$^{-2}$, we find the radio profile is between 80-100 per cent linearly polarized a…
A Broadband Emission Model of Magnetar Wind Nebulae
等离子体风引起的角动量损失被认为是孤立中子星（包括磁星）的普遍特征。由磁星提供动力的风星云使我们能够比较磁星与旋转动力磁星（RPPs）的风特性和自旋演化。本文建立了一个磁星风星云的宽带辐射模型。该模型是类似于过去的研究年轻的脉冲星风星云（PWNe）周围的RPP，但修改的应用程序MWNe的观测信息远远少于年轻的PWNe。我们应用该模型的MWN周围的最年轻的（$\sim$ 1 kyr）磁星1 E 1547.0-5408，具有最大的自旋功率$L_{\rm spin}$在所有的磁星。然而，与年轻的RPP相比，MWN是微弱的，因为1 E 1547.0-5408的低$L_{\rm spin}$。由于大多数参数仅受MWN的X射线通量上限的约束，因此我们采用PSR J1846-0258附近的年轻PWN Kes 75的模型参数，这是一个特殊的RPP，表现出类似磁星的行为。该模型预测了$γ$射线通量，该通量将在未来的TeV $γ$射线观测中被{ \it CTA}探测到。MWN光谱不允许我们检验1 E 1547.0-5408在其诞生时具有毫秒周期的假设，因为注入演化早期阶段的粒子遭受严重的绝热和同步加速器损失。进一步的观测和理论研究磁星周围的风星云需要约束磁星的风和自旋的属性。
The magnetar Swift J1822.3$-$1606 entered an outburst phase in 2011 July. Previous X-ray studies of its post-outburst rotational evolution yielded inconsistent measurements of the spin-inferred magnetic field. Here we present the timing behavior and flux relaxation from over two years of Swift, XTE, and Chandra observations following the outburst. We find that the ambiguity in previous timing solutions was due to enhanced spin down that resembles an exponential recovery following a glitch at the outburst onset. After fitting out the effects of the recovery, we measure a long-term spin-down rat…
We explore possible effects of a magnetar burst on the radio, X-ray, and gamma-ray flux of a pulsar wind nebula (PWN). We assume that the burst injects electron-positron pairs or powers the magnetic field and explore the total energy at injection and the spectral index needed in order to increase the X-ray flux by about one order of magnitude, as well as its decay time until reaching quiescence. We also explore magnetically powered phenomenology that could explain a temporary increase of the PWN synchrotron emitted flux and perhaps the relatively common lack of PWNe surrounding magnetars. This…
The long-lasting X-ray plateau emission in long gamma-ray bursts (GRBs) shows observational evidence for ongoing energy injection, which may be from magnetar spindown due to energy released via either magnetic dipole (MD) or gravitational wave (GW) radiation. In this paper, by systematically analyzing the {\em Swift}/XRT light curves detected before 2018 July, we find 45 light curves with a measured redshift that monotonically decay as a smooth broken power law. By assuming that the central engines of these GRBs are newly born magnetars, we measure the braking index $n$ of putative millisecond…
The fast radio burst FRB 121102 has repeated multiple times, enabling the identification of its host galaxy and of a spatially-coincident, compact, steady (`quiescent') radio synchrotron source. It was proposed that FRB 121102 is powered by a young flaring magnetar, embedded within a decades-old supernova remnant. Using a time-dependent one-zone model, we show that a single expanding magnetized electron-ion nebula (powered by the same outbursts likely responsible for the FRBs) can explain all the basic properties of the quiescent source (size, flux, self-absorption constraints) and the large b…
Swift J1818.0-1607 is a radio-loud magnetar with a spin period of 1.36 s and a dipolar magnetic field strength of B~3E14 G, which is very young compared to the Galactic pulsar population. We report here on the long-term X-ray monitoring campaign of this young magnetar using XMM-Newton, NuSTAR, and Swift from the activation of its first outburst in March 2020 until October 2021, as well as INTEGRAL upper limits on its hard X-ray emission. The 1-10 keV magnetar spectrum is well modeled by an absorbed blackbody with a temperature of kT_BB~1.1 keV, and apparent reduction in the radius of the emitt…
We report on the the long term monitoring campaign of the seemingly youngest magnetar Swift~J1818.0-1607 at radio and X-ray wavelengths over a span of one year. We obtained a coherent timing solution for the magnetar over the same time span. The frequency derivative of the magnetar shows systematic variation with the values oscillating about a mean value of $-$1.37$\times$10$^{-11}$ Hz s$^{-1}$. The magnitude of the variation in the frequency derivative reduces with time before converging on the mean value. We were able to identify four states in the spin-frequency derivative that were quantif…
We report on a new NuSTAR observation and on the ongoing Swift XRT monitoring campaign of the peculiar source 1E 161348-5055, located at the centre of the supernova remnant RCW 103, which is recovering from its last outburst in June 2016. The X-ray spectrum at the epoch of the NuSTAR observation can be described by either two absorbed blackbodies ($kT_{BB_1}$ ~ 0.5 keV, $kT_{BB_2}$ ~ 1.2 keV) or an absorbed blackbody plus a power law ($kT_{BB_1}$ ~ 0.6 keV, $Γ$ ~ 3.9). The observed flux was ~ 9 $\times$ 10$^{-12}$ erg s$^{-1}$ cm$^{-2}$, ~ 3 times lower than what observed at the outburst onset…
Assuming that the shallow-decaying phase in the early X-ray lightcurves of gamma-ray bursts (GRBs) is attributed to the dipole radiations (DRs) of a newborn magnetar, we present a comparative analysis for the magnetars born in death of massive stars and merger of compact binaries with long and short GRB (lGRB and sGRB) data observed with the {\em Swift} mission. We show that the typical braking index ($n$) of the magnetars is $\sim 3$ in the sGRB sample, and it is $\sim 4$ for the magnetars in the lGRB sample. Selecting a sub-sample of the magnetars whose spin-down is dominated by DRs ($n\less…
A Coherent Search for New Galactic Magnetars using Fermi/GBM and follow-up Swift/BAT: 7 Candidates and a Large Burst Catalog
Weizmann Institute of Science（魏茨曼科学研究所）；University of California at Santa Barbara（加州大学圣塔芭芭拉分校）；International Centre for Theoretical Sciences, Tata Institute of Fundamental Research（印度基本研究学院国际理论科学中心）
We report on the hard X-ray burst and the first ~100 days NICER monitoring of the soft X-ray temporal and spectral evolution of the newly-discovered magnetar Swift J1818.0-1607. The burst properties are typical of magnetars with a duration of $T_{90}=10\pm4$ ms and a temperature of $kT=8.4\pm0.7$ keV. The 2--8 keV pulse shows a broad, single peak profile with a pulse fraction increasing with time from 30% to 43%. The NICER observations reveal strong timing noise with $\dotν$ varying erratically by a factor of 10, with an average long-term spin-down rate of $\dotν=(-2.48\pm0.03)\times10^{-11}$~…
The wind nebula around magnetar Swift J1834.9-0846
我们报告了对磁星Swift J1834.9-0846及其周围扩展发射的两次深度XMM-牛顿观测的分析，这两次观测是在2014年3月和2014年10月，即源爆发后的2.5年和3.1年。磁星在第一次观测中仅被微弱地探测到，其吸收校正通量为$F_{\rm 0.5-10 keV}\approx4\times10^{-14}$ erg s $^{-1}$ cm $^{-2}$，而在第二次观测中的$3σ$上限约为$3\times10^{-14}$ erg s $^{-1}$ cm $^{-2}$。这一通量水平比2011年9月爆发开始时测量的通量低3个数量级以上。在两次观测中都可以清楚地看到以磁星位置为中心并向西南方向延伸的扩展发射;它最适合于高度吸收的幂律（PL），氢柱密度为$N_{\rm H}=8.0\times10^{22}$ cm $^{-2}$，PL光子指数为$Γ=2.2\pm0.2$。它的通量在两次观测之间是恒定的，为$F_{\rm 0.5-10 keV}=1.3\times10^{-12}$ erg s $^{-1}$ cm $^{-2}$。我们发现，从2005年到2014年的9年间，这种扩展发射的光谱形状或通量没有统计学上的显著变化。这些新的结果有力地支持了作为风星云的扩展发射性质，并坚定地确立了雨燕J1834.9-0846是第一个显示周围有风星云的磁星。此外，我们的研究结果意味…
Superluminous supernovae (SLSNe) are massive star explosions too luminous to be powered by traditional energy sources, such as radioactive 56Ni. These transients may instead be powered by a central engine, such as a millisecond pulsar or magnetar, whose relativistic wind inflates a nebula of high energy particles and radiation behind the expanding ejecta. We present 3D Monte Carlo radiative transfer calculations which follow the production and thermalization of high energy radiation from the nebula into optical radiation and, conversely, determine the gamma-ray emission that escapes the ejecta…
Radio-loud magnetars display a wide variety of radio-pulse phenomenology seldom seen among the population of rotation-powered pulsars. Spectropolarimetry of the radio pulses from these objects has the potential to place constraints on their magnetic topology and unveil clues about the magnetar radio emission mechanism. Here we report on eight observations of the magnetar Swift J1818.0$-$1607 taken with the Parkes Ultra-Wideband Low receiver covering a wide frequency range from 0.7 to 4 GHz over a period of 5 months. The magnetar exhibits significant temporal profile evolution over this period,…
We present the X-ray survey results of high-magnetic-field radio pulsars (high-B PSRs) with Swift/XRT. X-ray observations of the rotation-powered pulsars with the dipole magnetic field ${\it B_{\rm d}}$ near the quantum critical field ${\it B_{\rm q}}=4.4\times10^{13}$ G is of great importance for understanding the transition between the rotation-powered pulsars and the magnetars, because there are a few objects that have magnetar-like properties. Out of the 27 high-B PSRs that are in the ATNF pulsar catalogue but have not been reported or have no effective upper-limits in the X-ray bands, we …
The central engine of gamma-ray bursts (GRBs) is poorly constrained. There exist two main candidates: a fast-rotating black hole and a rapidly spinning magnetar. Furthermore, the X-ray plateaus are widely accepted by the energy injection into the external shock. In this paper, we systematically analyze the \emph{Swift}/XRT light curves of 101 GRBs having plateau phases and known redshifts (before May 2017). Since a maximum energy budget ($\sim2\times10^{52}$ erg) exists for magnetars but not for a black hole, this provides a good clue to identify the type of GRB central engine. We calculate th…
Recently, FRB 190520B with the largest extragalactic dispersion measure (DM), was discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The DM excess over the intergalactic medium and Galactic contributions is estimated as $\sim 900$ pc cm$^{-3}$, which is nearly ten times higher than other fast radio bursts (FRBs) host galaxies. The DM decreases with the rate $\sim0.1$ pc cm$^{-3}$ per day. It is the second FRB associated with a compact persistent radio source (PRS). The rotation measure (RM) is found to be larger than $1.8 \times 10^{5} \mathrm{rad} ~\mathrm{m}^{-2}…
We present a Chandra Director's Discretionary Time observation of PSR J1119-6127 and its compact X-ray pulsar wind nebula (PWN) obtained on 27 October 2016, three months after the Fermi and Swift detection of millisecond bursts in hard X-rays, accompanied by >160 times increase in flux. This magnetar-like activity, the first observed from a rotation-powered radio pulsar, provides an important probe of the physical processes that differentiate radio pulsars from magnetars. The post-burst X-ray spectrum of the pulsar can be described by a single powerlaw model with a photon index of 2.0\pm0.2 an…
Constraining the Properties of GRB Accreting Magnetar with $R/I$ Evolutionary Effects Using \emph{Swift}/XRT Data
CAS Key Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台空间天文与技术重点实验室）；School of Physics and Astronomy, Beijing Normal University（北京师范大学物理与天文学院）；Institute for Frontier in Astronomy and Astrophysics, Beijing Normal University（北京师范大学前沿交叉科学研究院（天体物理方向））；School of Mathematics and Science, Hebei GEO University（河北地质大学数理学院）；Niels Bohr International Academy and DARK, Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所尼尔斯·玻尔国际学院及DARK中心）；Department of Astronomy, Xiamen University（厦门大学天文学系）；Department of Physics, School of Physics and Materials Science, Nanchang University（南昌大学物理与材料科学学院物理学系）
Ofek (2017) identified FIRST J141918.9+394036 (hereafter FIRST J1419+3940) as a radio source sharing similar properties and host galaxy type to the compact, persistent radio source associated with the first known repeating fast radio burst, FRB 121102. Law et al. (2018) showed that FIRST J1419+3940 is a transient source decaying in brightness over the last few decades. One possible interpretation is that FIRST J1419+3940 is a nearby analogue to FRB 121102 and that the radio emission represents a young magnetar nebula (as several scenarios assume for FRB 121102). Another interpretation is that …
A magnetar outburst with atypical evolution: the case of Swift J1555.2-5402
European Space Science (ESA), European Space Astronomy Center (ESAC)（欧洲空间科学（ESA），欧洲空间天文中心（ESAC））；Institute of Space Sciences (ICE, CSIC)（空间科学研究所（ICE，CSIC））；Institut d’Estudis Espacials de Catalunya (IEEC)（加泰罗尼亚太空研究学院（IEEC））；INAF–Osservatorio Astronomico di Brera（意大利国家天体物理研究所-布雷拉天文台）；INAF–Osservatorio Astronomico di Roma（意大利国家天体物理研究所-罗马天文台）；INAF–Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano（意大利国家天体物理研究所-米兰空间天体物理学与宇宙物理研究所）；Università degli Studi di Milano Bicocca（米兰比可卡大学）；INAF–Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所-卡利亚里天文台）
Swift J1555.2-5402的非典型爆发演化特征，包括持续高温、缩小热点及延长明亮流量平台后快速变暗，挑战了现有爆发机制。
We searched the possible historical records for the young magnetar Swift J1818.0-1607, and found a guest star in AD 1798 that might be associated with it.
We report on multi-frequency radio observations of the new magnetar Swift J1818.0-1607, following it for more than one month with high cadence. The observations commenced less than 35 hours after its registered first outburst. We obtained timing, polarisation and spectral information. Swift J1818.0-1607 has an unusually steep spectrum for a radio emitting magnetar and also has a relatively narrow and simple pulse profile. The position angle swing of the polarisation is flat over the pulse profile, possibly suggesting that our line-of-sight grazes the edge of the emission beam. This may also ex…
