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Discovery of the first anti-glitch event in the rotation-powered pulsar PSR B0540-69

Speaker Dr. Youli TUO
Affiliation Institut für Astronomie und Astrophysik, Universität Tübingen
Date July 12, 2024 (Friday)
Time 2:30 p.m.
Venue MW103, 1/F, Meng Wah Complex, The University of Hong Kong


Using data from the Neutron star Interior Composition ExploreR (NICER) observatory, we identified a permanent spin frequency decrease of ∆ν = (1.04 ± 0.07) × 107 Hz around MJD 60132 in the rotation-powered pulsar PSR B0540-69, which exhibits a periodic signal at a frequency of ν 19.6 Hz. This points to an anti-glitch event, a sudden decrease of the pulsar’s rotational frequency without any major alteration in the pulse profile or any significant increase of the pulsed flux. Additionally, no burst activity was observed in association with the anti-glitch. To date, observations of the few known anti-glitches have been made in magnetars or accreting pulsars. This is the first anti-glitch detected in a rotation-powered pulsar. Given its radiatively quiet nature, this anti-glitch is possibly of internal origin. Therefore, we tentatively frame this event within a proposed mechanism for anti-glitches where the partial ‘evaporation’ of the superfluid component leads to an increase of the normal component’s moment of inertia and a decrease of the superfluid one.


Anyone interested is welcome to attend.