SIMBAD references

We have observed a glitch in the Crab pulsar (PSR B0531+21) in the 0.5-10 keV X-ray band with the X-Ray Pulsar Navigation-I (XPNAV-1) satellite. This glitch occurred around 2017 November 8. Observations at radio frequency by the Jodrell Bank observatory and the Lovell telescope have confirmed it to be the largest ever observed. We report the results of X-ray observation of this glitch. The measured rotation frequency increase of the Crab is Δν₀ = (14.3 ± 2.0) x 10^–6 Hz, corresponding to a fractional increase of Δν₀/ν₀ = (0.48 ± 0.09) x 10^–6. Two transient components in the rotation frequency change are detected: one is the short transient term of Δν_n1 = 6.6 x 10^–6 Hz with a timescale of 38.6 days and the other is the very short one of Δν_n2 = -1.35 x 10^–6 Hz with a timescale of 2.4 days. The step change in the rotation frequency derivative is determined to be Δ{dot}ν₀=(3.6±1.9)×10^–12 Hz s^–1. We also examine the relationship between the persistent offset Δ{dot}ν_p and Δν₀, giving Δ{dot}ν_p=7×10^–8×Δν₀. No significant X-ray flux changes are observed pre- and post-glitch.