摘要
We analyze the time and energy dependence of the Vela pulsar’s pulse profile using 13 yr observations from the Large Area Telescope on the Fermi Gamma-ray Space Telescope.It is found that the pulse profile of the Vela pulsar inγ-ray changes with time.We parameterize the pulse profile and find that different shape parameters show fiuctuations rather than gradual changes with time.However,these time variation trends are insignificant due to limited statistics.The pulse profile of the Vela pulsar displays clear energy dependence inγ-ray.Different shape parameters are accurately obtained or updated,especially the phase separations among different pulses.Their energy evolution trends are quantified for the first time,which will provide restrictions on currentγ-ray emission models.For the Vela pulsar,we also find a turning point at phase.Before and after this phase,the relative intensity of the pulse profile evolves with energy with the opposite trend.
基金
supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11903001,U1938109,U1838201,U1838202 and 42004004)
the Key Research Foundation of Education Ministry of Anhui Province(KJ2019A0787)
the Doctor Foundation of Anhui Jianzhu University 2019(2019QDZ14)。
