Weighted pulse profiles of PSR J1522-5735 before the first (blue line) and after the third (red line) glitch events respectively. Error bars show one sigma uncertainties. The average pattern pulse profiles used for timing analyzes are shown as a black dotted line. The gray dotted line indicates the background level. Credit: Panin et al., 2024.
By analyzing data from NASA’s Fermi Gamma-ray Space Telescope, Russian astronomers have detected anti-glitches in a gamma-ray pulsar designated PSR J1522-5735. The discovery, published September 28 on the preprint server arXivmakes PSR J1522-5735 one of the few known anti-glitch gamma-ray pulsars.
Pulsars are highly magnetized rotating neutron stars that emit beams of electromagnetic radiation. Observations show that many pulsars exhibit a sudden and gradual increase in rotation frequency, called glitches. However, in four pulsars, astronomers detected anti-glitches, that is, sudden drops in rotation frequency.
Discovered in 2013, PSR 1522-5735 is a radio-quiet pulsar propelled by gamma-ray rotation in the galactic plane, with a rotation period of approximately 204 milliseconds. It has a surface magnetic field level of approximately 3.61 TG, a rotational power of 289 decillion erg/s and its characteristic age is estimated at 51,800 years.
Today, a team of astronomers led by Alexander Panin of the Nuclear Research Institute of the Russian Academy of Sciences in Moscow, Russia, reports the detection of anti-glitches in PSR 1522-5735. The discovery was made based on data from Fermi’s Large Area Telescope (LAT) collected between August 2008 and April 2024.
“In this paper, we report on the temporal analysis of over 15 years of Fermi-LAT data for the PSR J1522-5735 pulsar. We detected eight glitch events, six of which were classified as anti-glitches,” the researchers wrote.
According to the study, the six anti-glitches in PSR J1522-5735 manifest as gradual changes in frequency and frequency-time derivative without post-glitch recovery terms. However, astronomers added that a rapid recovery from an anti-glitch within a few days cannot be completely ruled out due to the lack of comprehensive gamma-ray data.
All detected anti-glitches were found to be radiatively silent, exhibiting no significant variation in the shape of the pulse profile or energy flow. Therefore, the authors of the article assume that an internal mechanism is responsible for these phenomena in PSR J1522-5735.
The identification of silent radiation glitches in a spin-propelled pulsar like PSR J1522-5735 supports the hypothesis that their potential origin could lie within the neutron star. Further observations, focused on finding more anti-glitch pulsars, are needed to confirm this hypothesis.
In summarizing the results, the astronomers noted that PSR J1522-5735 is the newest addition to the short list of anti-glitch pulsars and that the two bugs detected in addition to the anti-glitch events appear to be a regular rotation bug and a tendril. -up glitch over-recovered at a spin-down.
More information:
AG Panin et al, The anti-glitch gamma ray pulsar PSR J1522-5735, arXiv (2024). DOI: 10.48550/arxiv.2409.19441
Journal information:
arXiv
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Quote: Anti-glitches detected in the gamma pulsar PSR J1522-5735 (October 8, 2024) retrieved October 8, 2024 from
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