Another state change collier or jaune enfant of the variable gamma
Gamma ray pulsars are rotating neutron stars collier or egyptien emitting gamma ray photons. Some of them are completely radio histoire d’or collier or jaune femme quiet, collier or attrape rêve which means that observations in other regimes are needed to learn about their properties.
PSR J2021+4026 (or 3FGL J2021.5+4026) is one of the brightest radio quiet collier or maille anglaise 42 cm gamma ray pulsars. In October 2011, observations of this object with Fermi revealed a sudden gamma ray flux drop and a change of the observed flux over a timescale of less than a week, which made it collier or piece the first known variable gamma swarovski collier or rose ray pulsar. The researchers also collier or maille forçat found collier or fillette that the spin down rate of this pulsar has changed. All in all, the object collier or maille ancienne switched from high gamma ray flux (HGF) and low spin down (LSD) rate state to low gamma ray flux (LGF) and high spin down (HSD) rate state.
Subsequent observations of PSR J2021+4026 have collier or torsadé prix shown collier or 24 carat that around December 2014, it extension collier or blanc returned to the HGF/LSD state over a timescale of a few months. Now, a team of astronomers led by Jumpei Takata of Huazhong University of Science and Technology in Wuhan, China, reports that the pulsar appears to have experienced one more state change. This assumption is based on the results of timing and spectral study of the source with Fermi.
“The timing and spectral analysis suggest that PSR J2021+4026 entered new collier or blanc pendentif LGF/HSD state at around 2018 February 1st,” the astronomers wrote in the paper.
According to collier or 9 carat the study, the long term evolution of the collier or blanc femme 18 carats gamma ray flux and timing behavior of PSR J2021+4026 are indicative of a new collier or occasion ebay state collier or algerien change near the first day of February 2018. collier or croix femme collier or personnalisable This state change occurred over a timescale of less than 10 days and its properties were similar to that of 2011, however, with a spin down rate in the new state slightly smaller than that measured after the event that took collier or maille américaine place almost vendre collier or avec aigue marine collier or a decade ago.
The researchers noted that the state switching of PSR J2021+4026 is likely caused by change of the magnetic field structure of the polar cap region. The astronomers added that it is possible that the crust cracking or other processes change the magnetic field structure or field strength in the polar cap region, and this process affects the created current and hence the pulsar’s spin down rate.
The study suggests that the state change in PSR J2021+4026 occurs every several years. However, the exact time interval is still unknown and further monitoring of this pulsar is needed to get more precise data.
Summing up the results, the astronomers emphasized that although state switching pulsars have been discovered in the radio bands, PSR J2021+4026 is the first switching pulsar discovered in gamma rays. Therefore, this source provides a unique opportunity to further study the collier or femme mode mechanisms state switching in gamma ray pulsars…