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Register a new userA very large glitch in PSR B2334+61
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Seven years of pulse time-of-arrival measurements have been collected from observations of the young pulsar PSR B2334+61 using the Nanshan radio telescope of Urumqi Observatory. A phase-connected solution has been obtained over the whole data span, 2002 August to 2009 August. This includes a very large glitch that occurred between 2005 August 26 and September 8 (MJDs 53608 and 53621). The relative increase in rotational frequency for this glitch, $Delta u_{g}/ u~sim~20.5times10^{-6}$, is the largest ever seen. Although accounting for less than 1% of the glitch, there were two well-defined exponential decay terms with time constants of 21 and 147 days respectively. There was also a large long-term increase in the spindown rate with $Deltadot u_p/dot u sim 0.011$ at the time of the glitch. A highly significant oscillation with a period of close to one year is seen in the post-glitch residuals. It is very unlikely that this can be accounted for by a pulsar position error or proper motion -- it appears to result from effects interior to the neutron star. Implications of these results for pulsar glitch models are discussed.
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One large glitch was detected in PSR B1737$-$30 using data spanning from MJD 57999 to 58406 obtained with the newly built Shanghai Tian Ma Radio Telescope (TMRT). The glitch took place at the time around MJD 58232.4 when the pulsar underwent an increase in the rotation frequency of $Delta u$ about 1.38$times 10^{-6}$ Hz, corresponding to a fractional step change of $Delta u / u$ $thicksim$ 8.39$times 10^{-7}$. Post$textrm{-}$glitch $ u$ gradually decreased to the pre$textrm{-}$glitch value. The frequency derivative was observed to undergo a step change of about $-$9$times 10^{-16}$ s$^{-2}$. Since July 1987, there are 36 glitches already reported in PSR B1737$-$30 including this one. According to our analysis, the glitch size distribution is well described by the power law with index of 1.13. The distribution of the interval between two adjacent glitches (waiting time $Delta T$) follows a Poissonian probability density function. For PSR B1737$-$30, the interval is prone to be long after a large glitch. But no correlation is found between glitch size and the interval since previous glitch.
We report the first detection of a glitch in the radio pulsar PSR J0908$-$4913 (PSR B0906$-$49) during regular timing observations by the Molonglo Observatory Synthesis Telescope (MOST) as part of the UTMOST project.
We report on the first XMM-Newton observation of the Vela-like pulsar PSR B2334+61. Spectral analysis reveals soft X-ray emission, with the bulk of the photons emitted at energies below ~1.5 keV. We find that the spectrum has a thermal origin and is well-fitted with either a blackbody or a magnetized, pure H atmospheric model. In the latter case, for a neutron star with a radius of 13 km and a magnetic field of 10e13 G, the best-fit gives an hydrogen column density nH = 0.33 x 10^22 cm^-2 and an effective temperature T_eff^infinity = 0.65 x 10^6 K, as measured at Earth. A comparison of the surface temperature of PSR B2334+61 obtained from this fit with cooling curves favor a medium mass neutron star with M ~ 1.45 solar masses or M ~ 1.6 solar masses, depending on two different models of proton superfluidity in the interior. We do not detect any pulsed emission from the source, and determine an upper limit of 5% for the modulation amplitude of the emission on the pulsars radio frequency.
We present high-sensitivity, wide-band observations (704 to 4032 MHz) of the young to middle-aged radio pulsar J1452-6036, taken at multiple epochs before and, serendipitously, shortly after a glitch occurred on 2019 April 27. We obtained the data using the new ultra-wide-bandwidth low-frequency (UWL) receiver at the Parkes radio telescope, and we used Markov Chain Monte Carlo techniques to estimate the glitch parameters robustly. The data from our third observing session began 3 h after the best-fitting glitch epoch, which we constrained to within 4 min. The glitch was of intermediate size, with a fractional change in spin frequency of $270.52(3) times 10^{-9}$. We measured no significant change in spin-down rate and found no evidence for rapidly-decaying glitch components. We systematically investigated whether the glitch affected any radiative parameters of the pulsar and found that its spectral index, spectral shape, polarisation fractions, and rotation measure stayed constant within the uncertainties across the glitch epoch. However, its pulse-averaged flux density increased significantly by about 10 per cent in the post-glitch epoch and decayed slightly before our fourth observation a day later. We show that the increase was unlikely caused by calibration issues. While we cannot exclude that it was due to refractive interstellar scintillation, it is hard to reconcile with refractive effects. The chance coincidence probability of the flux density increase and the glitch event is low. Finally, we present the evolution of the pulsars pulse profile across the band. The morphology of its polarimetric pulse profile stayed unaffected to a precision of better than 2 per cent.
The sudden spin-down in the rotation of magnetar 1E 2259+586 observed by Archibald et al. (2013) was a rare event. However this particular event, referred to as an anti-glitch, was followed by another event which Archibald et al. (2013) suggested could either be a conventional glitch or another anti-glitch. Although there is no accompanied radiation activity or pulse profile change, there is decisive evidence for the existence of the second timing event, judging from the timing data. We apply Bayesian Model Selection to quantitatively determine which of these possibilities better explains the observed data. We show that the observed data strongly supports the presence of two successive anti-glitches with a Bayes Factor, often called the odds ratio, greater than 40. Furthermore, we show that the second anti-gtlich has an associated frequency change $Delta u$ of $-8.2 times 10^{-8}$ Hz. We discuss the implications of these results for possible physical mechanisms behind this anti-glitch.
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