We report the detection of high energy gamma-ray emission from the young and energetic pulsar PSR B1509$-$58 and its pulsar wind nebula (PWN) in the composite supernova remnant SNR G320.4-1.2 (aka MSH 15-52). Using 1 year of survey data with the Fermi-Large Area Telescope (LAT), we detected pulsations from PSR B1509-58 up to 1 GeV and extended gamma-ray emission above 1 GeV spatially coincident with the PWN. The pulsar light curve presents two peaks offset from the radio peak by phases 0.96 $\pm$ 0.01 and 0.33 $\pm$ 0.02. New constraining upper limits on the pulsar emission are derived below 1 GeV and confirm a severe spectral break at a few tens of MeV. The nebular spectrum in the 1 - 100 GeV energy range is well described by a power-law with a spectral index of (1.57 $\pm$ 0.17 $\pm$ 0.13) and a flux above 1 GeV of (2.91 $\pm$ 0.79 $\pm$ 1.35) 10^{-9} cm^{-2} s^{-1}. The first errors represent the statistical errors on the fit parameters, while the second ones are the systematic uncertainties. The LAT spectrum of the nebula connects nicely with Cherenkov observations, and indicates a spectral break between GeV and TeV energies.
The Galactic supernova remnant (SNR) MSH 15-56 is a member of the class of composite SNRs that consists of the remnant shell and a displaced pulsar wind nebula (PWN). The earlier X-ray observations reported the comet-like morphology of the PWN and the ejecta distribution of the SNR. In this work, we present a study of MSH 15-56 using archival Suzaku data. We investigate the nature of the emission and spectral parameters of the remnant. The X-ray spectra are well fitted with a combination of a thermal and non-thermal model with temperature ~0.6 keV and photon index ~2.0. The slightly enhanced a…
We report the discovery of a diffuse radio emission around PSR J0855--4644 using an upgraded GMRT (uGMRT) observation at 1.35 GHz. The radio emission is spatially coincident with the diffuse X-ray pulsar wind nebula (PWN) seen with XMM but is much larger in extent compared to the compact axisymmetric PWN seen with Chandra. The morphology of the emission, with a bright partial ring-like structure and two faint tail-like features strongly resembles a bow shock nebula, and indicates a velocity of 100 km/s through the ambient medium. We conclude that the emission is most likely to be associated wi…
We have discovered an extended X-ray feature which is apparently associated with millisecond pulsar (MSP) PSR J1911-1114 from a XMM-Newton observation, which extends for ~1' and the radio timing position of PSR J1911-1114 is in the mid point of the feature. The orientation of the feature is similar to the proper motion direction of PSR J1911-1114. Its X-ray spectrum can be well-modeled by an absorbed power-law with a photon index of $Γ=1.8^{+0.3}_{-0.2}$. If this feature is confirmed to be a pulsar wind nebula (PWN), this will be the third case that an X-ray PWN found to be powered by a MSP.
We report on X-ray studies of the gamma-ray pulsar PSR J1418$-$6058 in the Rabbit pulsar wind nebula (PWN) carried out using archival Chandra and XMM-Newton observations. A refined timing analysis performed with the 120-ks XMM-Newton data finds significant ($p\approx10^{-7}$) pulsation at $P\approx110$ ms which is consistent with that measured with the Fermi large area telescope (LAT). In the Chandra image, we find extended emission around the pulsar similar to those seen around other pulsars in young PWNe, which further argues for association between PSR J1418$-$6058 and the Rabbit PWN. The X…
We present the results of the analysis of 8 years of Fermi-LAT data of the pulsar/pulsar wind nebula complex PSR J0205+6449/3C 58. Using a contemporaneous ephemeris, we carried out a detailed analysis of PSR J0205+6449 both during its off-peak and on-peak phase intervals. 3C 58 is significantly detected during the off-peak phase interval. We show that the spectral energy distribution at high energies is the same disregarding the phases considered, and thus that this part of the spectrum is most likely dominated by the nebula radiation. We present results of theoretical models of the nebula and…
The Cygnus\,OB2 region, $\sim 3.5-5~\text{Myr}$ old, contains one of the most significant populations of massive stars of the Milky Way. Such stars substantially contribute to producing large scale soft ($<2~\text{keV}$) diffuse X-ray emission. We also detected hard ($>3~\text{keV}$) diffuse X-ray emission in the direction of the pulsar PSR\,J2032+4127. The torus-shaped emission spans a $\approx 3'\times 2'$ jet-like structure. It is spatially coincident with the Fermi $γ$-ray source 4FGL\,J2032.3+4127. We suggest that the hard diffuse X-ray emission is the pulsar wind nebula bearing the pulsa…
In this work, we study the X-ray bow-shock nebula powered by the mature pulsar PSR B1929+10 using data from XMM-Newton, with an effective exposure of $\sim$ 300 ks, offering the deepest investigation of this system thus far. We found the X-ray axial outflow extends as long as $\sim$ 8 arc minute behind the proper motion direction, which is a factor of two longer than the result reported in the previous study. Furthermore, we found evidence of two faint lateral outflows extending laterally with respect to the proper motion. We also found indications of spectral hardening along the axial outflow…
We analyzed two Chandra observations of PSR J2055+2539 (for a total integration time of $\sim$130 ks) in order to measure its proper motion and study its two elongated nebular features. We did not detect the proper motion, setting an upper limit of 240 mas yr$^{-1}$ (3$σ$ level), that translates into an upper limit on the transverse velocity of $\sim$700 km s$^{-1}$, for an assumed distance of 600 pc. A deep H$α$ observation did not reveal the bow-shock associated with a classical pulsar wind nebula, thus precluding an indirect measurement of the proper motion direction. We determined the main…
We present a measurement of the proper motion of the presumed pulsar in the evolved composite supernova remnant (SNR) MSH 15-56 whose pulsar wind nebula (PWN) has been disrupted by the supernova (SN) reverse shock. Using Chandra X-ray observations acquired over a baseline of 15 years, we measure a pulsar velocity of 720 (+290/-215) km/s and a direction of motion of 14 +/- 22 degrees west of south. We use this measurement to constrain a hydrodynamical model for the evolution of this system and find that its morphology is well-described by an SNR expanding in an ambient density gradient that inc…
PSR J1809-1917 is a young ($τ=51$ kyr) energetic ($\dot{E}=1.8\times10^{36}$ erg s$^{-1}$) radio pulsar powering a pulsar wind nebula (PWN). We report on the results of three Chandra X-ray Observatory observations which show that the PWN consists of a small ($\sim 20''$) bright compact nebula (CN) and faint extended emission seen up to $2'$ from the pulsar. The CN is elongated in the northeast-southwest direction and exhibits morphological and flux variability on a timescale of a few months. We also find evidence of small arcsecond-scale jets extending from the pulsar along the same direction,…
We present the results of XMM-Newton observations toward the pulsar PSR J1826$-$1256, which lies at 5$^{\prime}$.4 from the centroid of the TeV source HESS J1826$-$130. These data show an elongated nebula with the pulsar located in the northern border with the emission in the direction of the peak of the very high energy source. The spectral study of the X-ray emission shows a clear softening of the photon index with increasing distance from the pulsar. We discuss the connection among the pulsar, its nebula, and the HESS source.
Based on a theoretical selection of pulsars as candidates for detection at X-ray energies, we present an analysis of archival X-ray observations done with Chandra and XMM-Newton of PSR J1747-2958 (the pulsar in the "Mouse" nebula), PSR J2021+3651 (the pulsar in the "Dragonfly" nebula), and PSR J1826-1256. X-ray pulsations from PSR J1747-2958 and PSR J1826-1256 are detected for the first time, and a previously reported hint of an X-ray pulsation from PSR J2021+3651 is confirmed with a higher significance. We analyze these pulsars' spectra in regards to the theoretically predicted energy distrib…
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…
In Dec. 2011 PSR B0540-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by ~36%. About 1000 days after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by 32+/-8%. After the SRT, the braking index n of PSR B0540-69 changes from n=2.12 to n=0.03 and then keeps this value for about five years before rising to n=0.9 in the following years. We find that most of the current models have difficulties in explaining the measured braking index. One exceptive model of the braking index evolution is the …
PSR B1706$-$44 is an energetic gamma-ray pulsar located inside supernova remnant (SNR) G343.1$-$2.3 and it powers a compact pulsar wind nebula (PWN) that shows torus and jet structure in X-rays. We present a radio study of the PWN using Australia Telescope Compact Array (ATCA) observations at 3, 6, 13, and 21\,cm. We found an overall arc-like morphology at 3 and 6\,cm, and the ``arc" shows two distinct peaks at 6\,cm. The radio emission is faint inside the X-ray PWN and only brightens beyond that. We develop a thick torus model with Doppler boosting effect to explain the radio PWN structure. T…
The near-infrared detection of PSR B0540-69 and its nebula
LMC中的PSR B 0540 -69被认为是蟹状星云脉冲星的孪生子，因为它具有相似的自旋参数、磁场和能量。它的光谱符合幂律，归因于同步辐射，就像年轻的蟹状星云和船帆座星云一样。近红外观测从未对PSR B 0540 -69进行过，对于确定光学幂律谱是否延伸到更长的波长或发生新的断裂至关重要，就像mIR中的蟹状星云和船帆座星云一样，暗示脉冲星磁层中的粒子能量和密度分布更加复杂。我们观察PSR B 0540 -69在J，H和Ks波段的VLT检测，第一次，在nIR和光谱的光学到nIR光谱。为了将脉冲星的辐射从脉冲星风星云中分离出来，我们利用NACO获得了高空间分辨率的自适应光学图像。我们可以在J、H和KS波段的图像中清楚地识别PSR B 0540 -69，并测量其通量（J=20.14，H=19.33，Ks=18.55，每个波段的总误差为+/- 0.1量级）。与可用的光学和近红外光度法的联合拟合与幂律光谱给出光谱指数α =0.70 +/-0.04。我们的NACO图像和HST光学图像之间的比较没有显示任何明显的差异，PWN形态作为波长的函数。PWN的光谱也符合单一的幂律，光谱指数α =0.56+/- 0.03，比脉冲星的略平坦。在VLT上使用NACO，我们在nIR中首次检测到PSR B 0540 -69及其PWN。由于PWN的角尺度很小（~4英寸），只有JWST的空间分辨率才能将脉冲星和PW…
Flux Evolution of PSR B0540--69 and the Spectral Energy Distribution of its Pulsar Wind Nebula
Institute of High Energy Physics, Chinese Academy of Sciences（中国科学院高能物理研究所）；University of Chinese Academy of Sciences（中国科学院大学）；Central China Normal University（华中师范大学）；Nanjing Normal University（南京师范大学）；TIANFU Cosmic Ray Research Center（天府宇宙线研究中心）
We report on broadband X-ray properties of the Rabbit pulsar wind nebula (PWN) associated with the pulsar PSR J1418-6058 using archival Chandra and XMM-Newton data, and a new NuSTAR observation. NuSTAR data above 10 keV allowed us to detect the 110-ms spin period of the pulsar, characterize its hard X-ray pulse profile, and resolve hard X-ray emission from the PWN after removing contamination from the pulsar and other overlapping point sources. The extended PWN was detected up to $\sim$20 keV and is well described by a power-law model with a photon index $Γ\approx$2. The PWN shape does not var…
It is believed that an isolated pulsar loses its rotational energy mainly through a relativistic wind consisting of electrons, positrons and possibly Poynting flux\cite{Pacini1973,Rees1974,Kennel1984}. As it expands, this wind may eventually be terminated by a shock, where particles can be accelerated to energies of X-ray synchrotron emission, and a pulsar wind nebula (PWN) is usually detectable surrounding a young energetic pulsar\cite{Pacini1973,Rees1974,Kennel1984}. However, the nature and/or energetics of these physical processes remain very uncertain, largely because they typically cannot…
Pulsar wind nebulae (PWNe) produced from supersonic runaway pulsars can render extended X-ray structures in the form of tails and prominent jets. In this Letter we report on the analysis of $\sim$130 ks observations of the PWN around PSR$\,$J1135-6055 obtained with the Chandra satellite. The system displays bipolar jet-like structures of uncertain origin, a compact nebula around the pulsar likely formed by the bow shock ahead of it, and a trailing tail produced by the pulsar fast proper motion. The spectral and morphological properties of these structures reveal strong similarities with the PW…
We report the results of X-ray (CXO) and radio (ATCA) observations of the pulsar wind nebula (PWN) powered by the young pulsar PSR J1016--5857, which we dub "the Goose" PWN. In both bands the images reveal a tail-like PWN morphology which can be attributed to pulsar's motion. By comparing archival and new CXO observations, we measure the pulsar's proper motion $μ=28.8\pm7.3$ mas/yr, yielding a projected pulsar velocity $v \approx 440\pm110$ km/s (at d=3.2 kpc); its direction is consistent with the PWN shape. Radio emission from the PWN is polarized, with the magnetic field oriented along the p…
Aims. The goal of this paper is to detect synchrotron emission from the relic electrons of the crushed pulsar wind nebula (PWN) HESS J1825-137 and to investigate the origin of the $γ$-ray emission from HESS J1826-130.\\ Methods. The study of HESS J1825-137 was carried out on the basis of new radio observations centred at the position of PSR J1826-1334 performed with the Karl G. Jansky Very Large Array at 1.4 GHz in configurations B and C. To investigate the nature of HESS J1826-130, we reprocessed unpublished archival data obtained with XMM-Newton.\\ Results. The new radio continuum image towa…
We present a detailed analysis of broadband X-ray observations of the pulsar PSR J1420-6048 and its wind nebula (PWN) in the Kookaburra region with Chandra, XMM-Newton, and NuSTAR. Using the archival XMM-Newton and new NuSTAR data, we detected 68 ms pulsations of the pulsar and characterized its X-ray pulse profile which exhibits a sharp spike and a broad bump separated by ~0.5 in phase. A high-resolution Chandra image revealed a complex morphology of the PWN: a torus-jet structure, a few knots around the torus, one long (~7') and two short tails extending in the northwest direction, and a bri…
One of the youngest known remnants of a core-collapse supernova (SN) in our Galaxy is G320.4$-$1.2/MSH 15-52 containing an energetic pulsar with a very short (1700 yr) spindown age and likely produced by a stripped-envelope SN Ibc. Bright X-ray and radio emission north of the pulsar overlaps with an H$α$ nebula RCW 89. The bright X-rays there have a highly unusual and quite puzzling morphology, consisting of both very compact thermally emitting knots and much more diffuse emission of nonthermal origin. We report new X-ray observations of RCW 89 in 2017 and 2018 with Chandra that allowed us to …
We present broad-band X-ray spectroscopy of the energetic components that make up the supernova remnant (SNR) Kesteven 75 using concurrent 2017 Aug 17-20 XMM-Newton and NuSTAR observations, during which the pulsar PSR J1846-0258 is found to be in the quiescent state. The young remnant hosts a bright pulsar wind nebula powered by the highly-energetic (Edot = 8.1E36 erg/s) isolated, rotation-powered pulsar, with a spin-down age of only P/2Pdot ~ 728 yr. Its inferred magnetic field (Bs = 4.9E13 G) is the largest known for these objects, and is likely responsible for intervals of flare and burst a…
