Through a detailed timing analysis of Fermi-LAT data, the rotational behavior of the γ-ray pulsar PSR J1522−5735 was tracked from 2008 August (MJD 54692) to 2024 January (MJD 60320). During this 15.4 yr period, two overrecovery glitches and four antiglitches were identified, marking a rare occurrence in rotation-powered pulsars (RPPs). The magnitudes of these (net) spin-down glitches were determined to be ∣Δν _g/ν∣ ∼ 10⁻⁸, well above the estimated detectability limit. For the two overrecovery glitches, the respective recovery fractions Q are 2.1(7) and 1.4(2). Further analysis showed no substantial variations in either the flux or pulse profile shape in any of these events, suggesting that small (net) spin-down glitches, unlike large events observed in magnetars and magnetar-like RPPs, may occur without leaving an impact on the magnetosphere. Within the framework of the vortex creep and vortex bending models, antiglitches and overrecoveries indicate the recoupling of vortex lines that moved inward as a result of a crustquake; meanwhile, the apparent fluctuations in the spin-down rate after the glitches occur as a result of the coupling of the oscillations of bent vortex lines to the magnetosphere.

Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are believed to be manifestations of magnetars. Typically, AXPs exhibit higher X-ray luminosities, whereas SGRs are generally fainter and display significantly high signal-to-noise ratios only during their outburst phases. In this work, we report the long-term timing evolution of four AXPs: 1E 2259+586, 4U 0142+61, 1RXS J170849.0–400910, and 1E 1841-045, which were regularly monitored with Neutron Star Interior Composition Explorer from 2017 to 2024. Over this period, we identify a total of 10 timing events. In addition to one glitch and one antiglitch in 1E 2259+586 reported in the literature, we detect another eight new timing events: five glitches, two antiglitches, and one unusual state transition event. Notably, both antiglitches were observed in 4U 0142+61, making it the most frequent source of such events, and there is a hint of regular evolution in its pulse profile. In the case of 1RXS J170849.0–400910, it continues to exhibit pronounced high-frequency timing anomalies and undergoes a state transition event. Finally, we study the evolution of the pulse profiles and find that the profiles of 1E 2259+586 and 4U 0142+61 both evolve. This is consistent with the earlier finding that pulse profile evolution is a generic feature of magnetars.

PSR J2021+4026 is a remarkable γ -ray pulsar exhibiting repeated transitions between high γ -ray flux (HGF) and low γ -ray flux (LGF) states. With 17 yr Fermi Large Area Telescope monitoring, we reveal persistent secular evolution and enhanced spin-down rate variability within individual emission states—beneath the quasiperiodic state transitions. After removing discrete jumps, the jump-corrected flux δF _γ shows a three-phase evolution: rise ( + 2.0 2 − 0.15 + 0.17 % yr − 1 ), decline ( − 3.7 2 − 0.47 + 0.34 % yr − 1 ), and rapid rise ( + 14 . 9 − 4.4 + 6.4 % yr − 1 ), with all rates quoted relative to the long-term mean flux 〈 F _γ 〉 = 7.8 × 10 ⁻¹⁰ erg cm ⁻² s ⁻¹ . Moreover, the flux of the LGF state is gradually approaching the stable HGF level at a rate of +0.72% ± 0.11% yr ⁻¹ . These results demonstrate that secular flux evolution in PSR J2021+4026 operates largely independently of discrete state transitions, yet jointly with them drives the system toward a stable high-flux equilibrium.

Soft γ -ray pulsars featuring broad single peaks exhibit different observational properties compared to ordinary double-peaked high-energy pulsars. These two types of pulsars are considered to be the result of different viewing angles. Therefore, the radiation characteristics of soft γ -ray pulsars play a crucial role in testing radiation models. However, the weak fluxes of the broad single-peak pulsars in the high-energy range have limited in-depth research on them in the past. In this work, the profile and spectral analysis of PSR B1509–58 from keV to GeV energies are performed using new observations from NICER, Insight-HXMT, and Fermi GBM-NaI/LAT. We find that the pulse profile narrows as the energy increases, and the FWHM can be fitted with FWHM = (0.35 ± 0.02) · ( E /1 keV) ^{−0.053 ± 0.009} . The phase-averaged spectrum fitted by a modified super exponential cutoff power law model reveals that the energy corresponding to the maximum luminosity E max is 2.1 ± 1 MeV. Furthermore, we fit the pulse profiles across different energy bands using a geometric annular gap model. Within the framework of this model, the observed narrowing of the pulse profile and the rapid softening of the phase-averaged spectrum can be interpreted as a result of the radiation angle moving away from the magnetic axis with increasing energy. The observational and modeling results support the existence of an annular gap acceleration region located inside the null-charge surface, suggesting that higher-energy radiation originates from areas closer to the surface of the neutron star.

We report on the timing and spectral properties of PSR J1838-0655 using joint observations from the Neutron Star Interior Composition Explorer (NICER) and the Nuclear Spectroscopic Telescope Array (NuSTAR). By disentangling the pulsar’s emission from its surrounding wind nebula across joint Chandra, NuSTAR, and NICER observations, we find the pulsar’s broadband X-ray spectrum (1.3–79 keV) is best-described by a broken power-law model. The model features photon indices of Γ₁ = 1.19 ± 0.07 and Γ₂ = 1.47 ± 0.02 below and above a break energy of E _b = 7.7 ± 0.8 keV. The resulting unabsorbed 2–10 keV flux from the pulsar is ( 9 . 5 − 0.3 + 0.4 ) × 1 0 − 12 erg cm − 2 s − 1 . Furthermore, timing analysis of NICER data spanning MJD 58250 to 60630 reveals a very large glitch occurring around MJD 59300, characterized by a frequency jump of Δν = 29.367(7) × 10⁻⁶ Hz, which can be well explained by the vortex creep model. Phase-resolved spectral analysis indicates a clear anticorrelation between the photon index and the pulse intensity, suggesting spectral hardening at the pulse peak.

Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are believed to be manifestations of magnetars. Typically, AXPs exhibit higher X-ray luminosities, whereas SGRs are generally fainter and display significantly high signal-to-noise ratios only during their outburst phases. In this work, we report the long-term timing evolution of four AXPs: 1E 2259+586, 4U 0142+61, 1RXS J170849.0-400910 and 1E 1841-045, which were regularly monitored with NICER from 2017 to 2024. Over this period, we identify a total of 10 timing events. In addition to one glitch and one anti-glitch in 1E 2259+586 reported in literature, we detect another 8 new timing events: 5 glitches, 2 anti-glitches, and 1 unusual state transition event. Notably, both anti-glitches were observed in 4U 0142+61, making it the most frequent source of such events, and there is a hint of regular evolution in its pulse profile. In the case of 1RXS J170849.0-400910, it continues to exhibit pronounced high-frequency timing anomalies and undergoes a state transition event. Finally, we study the evolution of the pulse profiles and find that the profiles of 1E 2259+586 and 4U 0142+61 both evolve. This is consistent with the earlier finding that pulse profile evolution is a generic feature of magnetars.