相关论文: Repeated state change of variable gamma-ray pulsar…

We investigate the high energy emission activities of two bright gamma-ray pulsars, PSR~J2021+4026 and Vela. For PSR~J2021+4026, the state changes in the gamma-ray flux and spin-down rate have been observed. We report that the long-term…

We undertake the first targeted search at 1.5 GHz for radio emission from the variable $\gamma$-ray pulsar PSR J2021$+$4026. This radio-quiet pulsar assumes one of two stable $\gamma$-ray emission states, between which it transitions on a…

PSR J2021+4026 is a remarkable $\gamma$-ray pulsar exhibiting repeated transitions between high $\gamma$-ray flux (HGF) and low $\gamma$-ray flux (LGF) states. With 17-yr Fermi-LAT monitoring, we reveal persistent secular evolution and…

A glitch of a pulsar is known as a sudden increase in the spin frequency and spin-down rate (frequency time derivative), and it can be caused by a sudden rel\ ease of the stress built up in the solid crust of the star or pinned vortices in…

Long-term monitoring of PSR J2021+4026 in the heart of the Cygnus region with the Fermi Large Area Telescope (LAT) unveiled a sudden decrease in flux above 100 MeV over a time scale shorter than a week. The "jump" was near MJD 55850 (2011…

Context. We have investigated the multiwavelength emission of PSR J2021+4026, the only isolated gamma-ray pulsar known to be variable, which in October 2011 underwent a simultaneous change in gamma-ray flux and spin-down rate, followed by a…

Pulsars are rapidly spinning and highly magnetized neutron stars, with highly stable rotational period and gradual spin-down over a long timescale due to the loss of radiation. Glitches refer to the events that suddenly increase the…

The goal of our work is to study the mode changes of the radio-quiet gamma-ray pulsar PSR J2021+4026 with improved detail. By accurately characterizing variations in the gamma-ray spectrum and pulse profile, we aim to relate the Fermi-LAT…

PSR J2021+4026 is a gamma-ray pulsar having variations in its spin-down rate and gamma-ray flux. Its variations in timing and emission are correlated, e.g., a larger spin-down rate for a low gamma-ray flux. We show that the mode change in…

With the twelve-year long observations by {\sl Fermi}-LAT, we discover two pairs of spin-down state transitions of PSR J1124--5916, making it the second young pulsar detected to have such behaviors. PSR J1124--5916 shows mainly two states…

We present radio, X-ray, and gamma-ray observations which reveal that the binary millisecond pulsar / low-mass X-ray binary transition system PSR J1023+0038 has undergone a transformation in state. Whereas until recently the system harbored…

Pulsars are the most numerous class of Galactic gamma-ray sources detected by the Fermi Large Area Telescope (LAT). Young pulsars occasionally experience sudden timing discontinuities called glitches, characterized by rapid changes in…

PSR~J2021+4026 showed a sudden decrease in the gamma-ray emission at the glitch that occurred around 2011, October 16, and a relaxation of the flux to the pre-glitch state at around 2014 December. We report X-ray analysis results of the…

The 1.69 ms spin period of PSR J1227-4853 was recently discovered in radio observations of the low-mass X-ray binary XSS J12270-4859 following the announcement of a possible transition to a rotation-powered millisecond pulsar state,…

In this paper, we report a detailed investigation of the multiwavelength properties of a newly detected gamma-ray pulsar, PSR J2021+4026, in both observational and theoretical aspects. We firstly identify an X-ray source in the XMM-Newton…

We study the spin-down changes of PSR B1859$+$07 over a period of more than 28 years of radio observation. We identify that the time derivative of the rotational frequency ($\nu$) varies quasi-periodically with a period of $\sim$350 days,…

We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar PSR J0030+0451 with the Large Area Telescope (LAT) on the \emph{Fermi} Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR…

PSR B1931+24 (J1933+2421) behaves as an ordinary isolated radio pulsar during active phases that are 5-10 days long. However, the radio emission switches off in less than 10 seconds and remains undetectable for the next 25-35 days, then it…

PSR J0742-2822 exhibits two distinct emission states that are identified by discrete changes in the observed pulse profile. These changes have previously been shown to correlate with changes in the derivative of the pulse frequency. In this…

We present an analysis of 4 nulling pulsars with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). For PSR J1649+2533, our results suggest mode changing rather than subpulse drifting as previously reported at lower…