Previous works have suggested a correlation between the X-ray luminosity L x and the rotational luminosity L rot of the radio pulsars. However, none of the obtained regression lines are statistically acceptable due to large scatters. We construct a statistical model which has an intrinsic L x -L rot relation and reproduces the observed L x distribution about it by using a Monte Carlo simulator, which takes into account the effects obscuring the intrinsic relation, i.e., the anisotropy of radiation, additional heating, uncertainty in distance and detection limit of the instruments. From the ATNF pulsar catalog we collect 57 'ordinary radio pulsars' with significant detection and 42 with upper limits. The sample does not include the high-magnetic field pulsars (> 10 13 G), which are separately analyzed. We obtain a statistically acceptable relation L x (0.5−10keV) = 10 31.69 (L rot /L 0 ) c1 with c 1 = 1.03±0.27 and L 0 = 10 35.38 . The distribution about the obtained L x -L rot relation is reproduced well by the simulator. Pulsars with abnormally high L x fall into two types: one is the soft gamma-ray pulsars, and the other is thermally bright pulsars in comparison with the standard cooling curve. On the other hand, pulsars showing low L x are found to have dim pulsar wind nebulae. We argue that there is an unknown mechanism that governs both the magnetospheric emission and the pulsar wind nebulae, and it might involve the production rate of electron-positron pairs. The high-field pulsars form a distinctive population other than the ordinary pulsars due to their excess luminosities.

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The Crab pulsar and its nebula are among the most studied astrophysical systems, and constitute one of the most promising environments where high energy processes and particle acceleration can be investigated. They are the only objects for which previous X-ray polarisation has been reported. We present here the first Imaging X-ray Polarimetry Explorer (IXPE) observation of the Crab pulsar and nebula. The total pulsar pulsed emission in the [2-8] keV energy range is unpolarised. Significant polarisation up to 15% is detected only in the core of the main peak. The nebula has a total space integrated polarised degree of 20% and polarisation angle of 145 • . The polarised maps show a large variation in the local polarisation, and regions with polarised degree up to 45-50%. The polarisation pattern suggests a predominantly toroidal magnetic field.

We present the results of Suzaku X-ray follow-up observation of weak-lensingdetected halos in the field around galaxy cluster ZwCl0823.2+0425. We clearly detected X-ray emission associated with most of these halos and determined their detailed physical parameters such as X-ray luminosity, temperature, and metal abundance, for the first time. We find that the X-ray luminosity -temperature relation for these halos agrees with former typical results. With mass determined from the weak gravitational lensing data, the mass-temperature relation for them is also investigated and found to be consistent with the prediction from a simple self-similar model and results of the previous studies with both lensing and X-ray data. We would like to 1 emphasize that the self-similar scaling relation of mass and temperature is shown here for the first time using a weak-lensing selected sample, whereas previous studies of the mass scaling relation used X-ray-selected samples of clusters. Therefore, our study demonstrates importance of X-ray follow-up observations of shear-selected clusters, and shows that a joint X-ray and lensing analysis will be crucial for clusters discovered by the forthcoming weak-lensing surveys, such as the one planned with Subaru/Hyper-Suprime-Cam.

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 B d near the quantum critical field B q = 4.4 × 10 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 analyze the Swift/XRT data for 21 objects, where 6 objects are newly observed and 15 objects are taken from the archival data. As a result, we have new 3σ upper-limits for all the 21 objects. Since the upper-limits are tight, we conclude that we do not find any magnetarlike high-B PSRs such as PSR J1819−1458. The probability of the high Xray efficiency in the high-B PSRs is obtained to be 11% − 29%. Combining the previous observations, we discuss which parameter causes magnetar-like properties. It may be suggested that the magnetar-like properties appear only when B d 10 13.5 G for the radio pulsar population. This is true even if the radio-quiet high-B RPP are included.2 Watanabe et al. INTRODUCTIONIsolated neutron stars are known to have two major populations according to the source of their energy. One is the rotation-powered pulsars (RPPs) (for a review, see Beskin et al. 2015). These are mostly observed as radio pulsars (PSRs) or gamma-ray pulsars. The other population is the high magnetic pulsars, called magnetars for short (for a review, see Beloborodov 2017 andTurolla et al. 2015). These are characterised by frequent bursting activity, lasting from a fraction of a second to several tens of seconds, and by high X-ray luminosity larger than the spin-down luminosity L rot . What causes this distinctive manifestation of neutron stars as either RPPs or magnetarsis not yet understood. The dipole component of the neutron star magnetic field can be inferred from the spin period P and its time derivative P as B d ≈ 1.1×10 12 (P/1s) 1/2 ( P/10 −15 ) 1/2 G.Since most magnetars have a very strong dipole magnetic field exceeding the quantum critical field B q = m 2 c 3 / e = 4.4 × 10 13 G, it was thought that the strength of the dipole field is the key parameter. However, discovery of the "weak-field magnetar" SGR 0418+5729, whose dipole field B d ∼ 6.1 × 10 12 G is much less than B q Rea et al. 2010Rea et al. , 2013, indicates that dipole field strength is not always essential. Theoretically, the toroidal field is proposed to play an essential role for magnetar activity (Pons & Perna 2011). The toroidal field together with the poloidal field evolves interactively from very large values 10 14 G at birth to their present state, and is expected to form multi-pole fields that cause bursts and extra heating.A small group of RPPs called high-magnetic-field RPPs (high-B RPPs), some of which are radio-quiet pulsars, may be key to understand the strong magnetic fields...