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Register a new userOne large glitch in PSR B1737-30 detected with the TMRT
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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.
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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.
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 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.
PSR B1259-63 is a middle-aged radio pulsar (P=48 ms, tau=330 kyr, Edot=8.3*10^{35} erg/s) in an eccentric binary (P_orb =3.4 yr, e=0.87) with a high-mass Be companion, SS 2883. We observed the binary near apastron with the Chandra ACIS detector on 2009 May 14 for 28 ks. In addition to the previously studied pointlike source at the pulsars position, we detected extended emission on the south-southwest side of this source. The pointlike source spectrum can be described by the absorbed power-law model with the hydrogen column density N_H = (2.5+/-0.6)*10^{21} cm^{-2}, photon index Gamma = 1.6+/-0.1, and luminosity L_{0.5-8 keV} = 1.3*10^{33} d_3^2 erg/s, where d_3 is the distance scaled to 3 kpc. This emission likely includes an unresolved part of the pulsar wind nebula (PWN) created by the colliding winds from the pulsar and the Be companion, and a contribution from the pulsar magnetosphere. The extended emission apparently consists of two components. The highly significant compact component looks like a southward extension of the pointlike source image, seen up to about 4 arcsec from the pulsar position. Its spectrum has about the same slope as the pointlike source spectrum, while its luminosity is a factor of 10 lower. We also detected an elongated feature extended ~15 arcsec southwest of the pulsar, but significance of this detection is marginal. We tentatively interpret the resolved compact PWN component as a shocked pulsar wind blown out of the binary by the wind of the Be component, while the elongated component could be a pulsar jet.
We report the first detection of an optical millisecond pulsar with the fast photon counter Aqueye+ in Asiago. This is an independent confirmation of the detection of millisecond pulsations from PSR J1023+0038 obtained with SiFAP at the Telescopio Nazionale Galileo. We observed the transitional millisecond pulsar PSR J1023+0038 with Aqueye+ mounted at the Copernicus telescope in January 2018. Highly significant pulsations were detected. The rotational period is in agreement with the value extrapolated from the X-ray ephemeris, while the time of passage at the ascending node is shifted by $11.55 pm 0.08$ s from the value predicted using the orbital period from the X-rays. An independent optical timing solution is derived over a baseline of a few days, that has an accuracy of $sim 0.007$ in pulse phase ($sim 12$ $mu$s in time). This level of precision is needed to derive an accurate coherent timing solution for the pulsar and to search for possible phase shifts between the optical and X-ray pulses using future simultaneous X-ray and optical observations.
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