PSR J0742-2822 is known for its quasi-periodic changes in the observed pulse profile and spindown rate.In this paper,we analyzed 13 years of timing data obtained with the Nanshan 25-m radio telescope and the Parkes 64...PSR J0742-2822 is known for its quasi-periodic changes in the observed pulse profile and spindown rate.In this paper,we analyzed 13 years of timing data obtained with the Nanshan 25-m radio telescope and the Parkes 64-m radio telescope.We found that the average values of the spin-down rate((v))of this pulsar changed in four different states.We investigated the correlation between v and W50,and ascertained that the correlation changed in different states.Moreover,not all the changes in states and correlation can be associated with glitch activities.We examined the long term evolution ofγ-ray flux(0.1-300 GeV)and the pulse profiles corresponding to the four different states using Fermi-LAT Pass8(P8 R3)data from 2008 August 5 to 2019 October 1.We did not detect a significant change inγ-ray flux or the pulse profile.Our results suggest that the connection between pulsar rotation and emission is more complex than previously reported for this pulsar.展开更多
Pulsar timing measurements with a 26 m radio telescope at Nanshan between 2000 and 2014 were used to search for glitch events. The data span of nine pulsars ranges from 11.6 to 14.2 yr, and 16 new glitch events were i...Pulsar timing measurements with a 26 m radio telescope at Nanshan between 2000 and 2014 were used to search for glitch events. The data span of nine pulsars ranges from 11.6 to 14.2 yr, and 16 new glitch events were identified in nine pulsars. Glitch parameters were determined through fitting the timing residuals data. All 16 glitches have a small fractional size. Six new glitches have been detected in PSR J1833-0827, making it another frequent glitching pulsar. Some of the 16 glitches may experience exponential or linear recovery, but it is unlikely for us to make further analyses with the large gap in the data set. All the glitch rates obtained from Nanshan are higher than that from Jodrell Bank Observatory. The small glitch size and high glitch rate could possibly attribute to the high observation cadence.展开更多
Flux densities are basic observation parameters to describe pulsars.In the most updated pulsar catalog,24%of the listed radio pulsars have no flux density measurement at any frequency.Here,we report the first flux den...Flux densities are basic observation parameters to describe pulsars.In the most updated pulsar catalog,24%of the listed radio pulsars have no flux density measurement at any frequency.Here,we report the first flux density measurements,spectral indices,pulse profiles,and correlations of the spectral index with pulsar parameters for 19 pulsars employing the Ultra-Wideband Low receiver system installed on the Parkes radio telescope.The results for spectral indices of 17 pulsars are in the range between-0.6 and-3.10.The polarization profiles of thirteen pulsars are shown.There is a moderate correlation between the spectral index and spin frequency.For most pulsars detected,the signal-to-noise ratio of pulse profile is not high,so DM,Faraday rotation measure,and polarization cannot be determined precisely.Twenty-nine pulsars were not detected in our observations.We discuss the possible explanations for why these pulsars were not detected.展开更多
基金supported by the National Key Research and Development Program of China(2016YFA0400804,2017YFA0402602,2018YFA0404603 and 2018YFA0404703)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administered by the Chinese Academy of Sciences(CAS),the National Natural Science Foundation of China(Grant Nos.11873080,U1831102,U1731238,U1938109,U1838104,11873040,11573010,11661161010,U1631103 and U1838102)+4 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences,the CAS“Light of West China”Program(Nos.2018-XBQNXZ-B-023,2018-XBQNXZ-B-025 and 2016-QNXZ-B-24)the Tianshan Youth Program No.2018Q039the Open Project Program of the Key Laboratory of FAST,NAOC,Chinese Academy of Sciences,the China Postdoctoral Science Foundation grant(2019M650847)the 2016 and 2018 Project of Xinjiang Uygur Autonomous Region of China for Flexibly Fetching in Upscale Talents and the Science and Technology Fund of Guizhou Province(Grant Nos.(2016)–4008 and(2017)5726–37)part of the Australia Telescope National Facility which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO。
文摘PSR J0742-2822 is known for its quasi-periodic changes in the observed pulse profile and spindown rate.In this paper,we analyzed 13 years of timing data obtained with the Nanshan 25-m radio telescope and the Parkes 64-m radio telescope.We found that the average values of the spin-down rate((v))of this pulsar changed in four different states.We investigated the correlation between v and W50,and ascertained that the correlation changed in different states.Moreover,not all the changes in states and correlation can be associated with glitch activities.We examined the long term evolution ofγ-ray flux(0.1-300 GeV)and the pulse profiles corresponding to the four different states using Fermi-LAT Pass8(P8 R3)data from 2008 August 5 to 2019 October 1.We did not detect a significant change inγ-ray flux or the pulse profile.Our results suggest that the connection between pulsar rotation and emission is more complex than previously reported for this pulsar.
基金supported by the National SKA Program of China(No.2020SKA0120100)the National Natural Science Foundation of China (NSFC+3 种基金No.12041304)Youth Innovation Promotion Association of the Chinese Academy of Sciencesthe CAS Jianzhihua project,Guizhou Provincial Science and Technology Foundation (No.ZK2022304)Heaven Lake Hundred-Talent Program of Xinjiang Uygur Autonomous Region of China。
文摘Pulsar timing measurements with a 26 m radio telescope at Nanshan between 2000 and 2014 were used to search for glitch events. The data span of nine pulsars ranges from 11.6 to 14.2 yr, and 16 new glitch events were identified in nine pulsars. Glitch parameters were determined through fitting the timing residuals data. All 16 glitches have a small fractional size. Six new glitches have been detected in PSR J1833-0827, making it another frequent glitching pulsar. Some of the 16 glitches may experience exponential or linear recovery, but it is unlikely for us to make further analyses with the large gap in the data set. All the glitch rates obtained from Nanshan are higher than that from Jodrell Bank Observatory. The small glitch size and high glitch rate could possibly attribute to the high observation cadence.
基金the National Natural Science Foundation of China(Grant No.NSFC12041304)National SKA Program of China(No.2020SKA0120100)+3 种基金Youth Innovation Promotion Association of Chinese Academy of SciencesNational Key Research and Development Program of China(No.2017YFA0402602)the CAS Jianzhihua projectHeaven Lake Hundred-Talent Program of Xinjiang Uygur Autonomous Region of China。
文摘Flux densities are basic observation parameters to describe pulsars.In the most updated pulsar catalog,24%of the listed radio pulsars have no flux density measurement at any frequency.Here,we report the first flux density measurements,spectral indices,pulse profiles,and correlations of the spectral index with pulsar parameters for 19 pulsars employing the Ultra-Wideband Low receiver system installed on the Parkes radio telescope.The results for spectral indices of 17 pulsars are in the range between-0.6 and-3.10.The polarization profiles of thirteen pulsars are shown.There is a moderate correlation between the spectral index and spin frequency.For most pulsars detected,the signal-to-noise ratio of pulse profile is not high,so DM,Faraday rotation measure,and polarization cannot be determined precisely.Twenty-nine pulsars were not detected in our observations.We discuss the possible explanations for why these pulsars were not detected.
