scholarly journals Jiamusi pulsar observations

2020 ◽  
Vol 644 ◽  
pp. A73
Author(s):  
P. F. Wang ◽  
J. L. Han ◽  
L. Han ◽  
B. Y. Cai ◽  
C. Wang ◽  
...  

Aims. Most pulsar nulling observations have been conducted at frequencies lower than 1400 MHz. We aim to understand the nulling behaviors of pulsars at relatively high frequencies, and to decipher whether or not nulling is caused by a global change in the pulsar magnetosphere. Methods. We used the Jiamusi 66 m telescope to observe 20 bright pulsars at 2250 MHz with unprecedented lengths of time. We estimated the nulling fractions of these pulsars, and identified the null and emission states of the pulses. We also calculated the nulling degrees and scales of the emission-null pairs to describe the distributions of emission and null lengths. Results. Three pulsars, PSRs J0248+6021, J0543+2329, and J1844+00, are found to null for the first time. The details of null-to-emission and emission-to-null transitions within the pulse window are observed for the first time for PSR J1509+5531, which is a low-probability event. A complete cycle of long nulls with timescales of hours is observed for PSR J1709−1640. For most of these pulsars, the K-S tests of nulling degrees and nulling scales reject the hypothesis that null and emission are caused by random processes at high significance levels. Emission-null sequences of some pulsars exhibit quasi-periodic, low-frequency or featureless modulations, which might be related to different origins. During transitions between emission and null states, pulse intensities have diverse tendencies for variation. Significant correlations are found between respectively nulling fraction, nulling cadence, and nulling scale and the energy loss rate of the pulsars. Combined with the nulling fractions reported in the literature for 146 nulling pulsars, we find that statistically large nulling fractions are more tightly related to pulsar period than to characteristic age or energy-loss rate.

1986 ◽  
Vol 60 (10) ◽  
pp. 3422-3426 ◽  
Author(s):  
Alexander J. Anastassiades ◽  
Efstathios G. Sideris

2016 ◽  
Author(s):  
Meenhaz Ansari ◽  
S. S. Z. Ashraf ◽  
Afzal Ahmad

Applied laser ◽  
2014 ◽  
Vol 34 (6) ◽  
pp. 589-592
Author(s):  
张程 Zhang Cheng ◽  
陈雪辉 Chen Xuehui ◽  
袁根福 Yuan Genfu

1983 ◽  
Vol 29 (1) ◽  
pp. 131-137 ◽  
Author(s):  
M. H. A. Hassan ◽  
P. H. Sakanaka

The energy loss rate, Ė, of test ions injected with velocity V into a Maxwellian electron-ion plasma in the presence of an external magnetic field, is studied. Most of the integrals appearing in the expression for Ė are evaluated analytically and the remaining integrals are evaluated numerically for various values of the parameters η = Ωe / ωe, x = V/ve, r = Te/Ti, and the angle of injection θ. It is shown that the effect of the magnetic field is rather small except for η > 1, the temperature ratio is important for small x (x ≤ 0·2), and the injection angle is not important.


Author(s):  
GYULA FODOR ◽  
PÉTER FORGÁCS ◽  
MÁRK MEZEI

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