In:
The Astrophysical Journal, American Astronomical Society, Vol. 896, No. 1 ( 2020-06-01), p. 55-
Abstract:
Glitches correspond to sudden jumps of rotation frequency ( ν ) and its derivative ( ) of pulsars, the origin of which remains not well understood yet, partly because the jump processes of most glitches are not well time-resolved. There are three large glitches of the Crab pulsar, detected in 1989, 1996, and 2017, which were found to have delayed spin-up processes before the normal recovery processes. Here we report two additional glitches of this pulsar that occurred in 2004 and 2011 for which we discovered delayed spin-up processes, and present refined parameters of the largest glitch, which occurred in 2017. The initial rising time of the glitch is determined as 〈 0.48 hr. The two glitches that occurred in 2004 and 2011 had delayed spin-up time scales ( τ 1 ) of 1.7 ± 0.8 days and 1.6 ± 0.4 days, respectively. We also carried out a statistical study of these five glitches with observed spin-up processes. We find that the Δ ν versus relation of these five glitches is similar to those with no detected delayed spin-up process, indicating that they are similar to the others in nature except that they have larger amplitudes. For these five glitches, the amplitudes of the delayed spin-up process ( ) and recovery process (Δ ν d2 ), their time scales ( τ 1 , τ 2 ), and permanent changes in spin frequency (Δ ν p ) and total frequency step (Δ ν g ) have positive correlations. From these correlations, we suggest that the delayed spin-up processes are common for all glitches, but are too short and thus difficult to be detected for most glitches.
Type of Medium:
Online Resource
ISSN:
0004-637X
,
1538-4357
DOI:
10.3847/1538-4357/ab8db6
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2020
detail.hit.zdb_id:
2960-9
detail.hit.zdb_id:
1473835-1
SSG:
16,12
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