2021A&A...647A..25E


Query : 2021A&A...647A..25E

2021A&A...647A..25E - Astronomy and Astrophysics, volume 647A, 25-25 (2021/3-1)

Small glitches and other rotational irregularities of the Vela pulsar.

ESPINOZA C.M., ANTONOPOULOU D., DODSON R., STEPANOVA M. and SCHERER A.

Abstract (from CDS):


Context. Glitches are sudden increases in the rotation rate ν of neutron stars, which are thought to be driven by the neutron superfluid inside the star. The Vela pulsar presents a comparatively high rate of glitches, with 21 events reported since observations began in 1968. These are amongst the largest known glitches (17 of them have sizes Δν/ν≥10–6) and exhibit very similar characteristics. This similarity, combined with the regularity with which large glitches occur, has turned Vela into an archetype of this type of glitching behaviour. The properties of its smallest glitches, on the other hand, are not clearly established.
Aims. We explore the population of small-amplitude, rapid rotational changes in the Vela pulsar and determine the rate of occurrence and sizes of its smallest glitches. This will help advance our understanding of the actual distribution of glitch sizes and inter-glitch waiting times in this pulsar, which has implications for theoretical models of the glitch mechanism.
Methods. High-cadence observations of the Vela pulsar were taken between 1981 and 2005 at the Mount Pleasant Radio Observatory. An automated systematic search was carried out that investigated whether a significant change of spin frequency ν and/or the spin-down rate dν/dt takes place at any given time.
Results. We find two glitches that have not been reported before, with respective sizes Δν/ν of (5.55±0.03)x10–9 and (38±4)x10–9. The latter is followed by an exponential-like recovery with a characteristic timescale of 31d. In addition to these two glitch events, our study reveals numerous events of all possible signatures (i.e. combinations of Δν and Δdν/dt signs), all of them small with |Δν|/ν<10–9, which contribute to the Vela timing noise.
Conclusions. The Vela pulsar presents an under-abundance of small glitches compared to many other glitching pulsars, which appears genuine and not a result of observational biases. In addition to typical glitches, the smooth spin-down of the pulsar is also affected by an almost continuous activity that can be partially characterised by small step-like changes in ν, dν/dt or both. Simulations indicate that a continuous wandering of the rotational phase, following a red spectrum, could mimic such step-like changes in the timing residuals.

Abstract Copyright: © ESO 2021

Journal keyword(s): stars: neutron - pulsars: general - pulsars: individual: PSR B0833-45 - stars: rotation

Errata: erratum vol. 649, art. C2 (2021)

Simbad objects: 9

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Number of rows : 9
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
#notes
1 PSR J0205+6449 Psr 02 05 37.92 +64 49 42.8           ~ 248 1
2 V* CM Tau Psr 05 34 31.9474694616 +22 00 52.153698024           ~ 5250 0
3 PSR J0537-6910 Psr 05 37 46.66 -69 10 17.1           ~ 282 1
4 PSR J0631+10 Psr 06 31 27.369 +10 37 05.63           ~ 134 0
5 NAME Vela Pulsar Psr 08 35 20.65525 -45 10 35.1545     15.10     ~ 2313 1
6 PSR B1737-30.2 Psr 17 40 33.82 -30 15 43.5           ~ 214 0
7 PSR B1757-24 Psr 18 01 00.016 -24 51 27.50           ~ 244 1
8 PSR B1800-21 Psr 18 03 51.45 -21 37 08.1           ~ 260 1
9 PSR B1823-13 Psr 18 26 13.06 -13 34 48.1           ~ 419 1

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