PULSAR GLITCHES spin frequency time Danai Antonopoulou Centrum - - PowerPoint PPT Presentation

▶
pulsar glitches
SMART_READER_LITE
LIVE PREVIEW

PULSAR GLITCHES spin frequency time Danai Antonopoulou Centrum - - PowerPoint PPT Presentation

Mar 14, 2024 14 likes •208 views

PULSAR GLITCHES spin frequency time Danai Antonopoulou Centrum Astronomiczne im. Miko aja Kopernika What are pulsar glitches? 11.197 fast spin-up 11.1947 spin frequency (Hz) 10 3 100 Hz 11.1946 11.196 51520

slide-1
SLIDE 1

PULSAR GLITCHES

Danai Antonopoulou

Centrum Astronomiczne im. Mikołaja Kopernika

time spin frequency

slide-2
SLIDE 2

What are pulsar glitches?

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

50000 50500 51000 51500 52000

  • 15700
  • 15650
  • 15600
  • 15550

11.194 11.195 11.196 11.197

51520 51540 51560 51580 51600 11.1946 11.1947

spin frequency ν (Hz) MJD (days)

spin-down rate ˙ ν (10−15 Hz/s)

10−3 ∆ν 100 µHz

★ increase in spin-down ★ fast spin-up

∆ ˙ ν < 0

★ slow relaxation

(~weeks-years) superfluid dynamics

slide-3
SLIDE 3

What could be causing them?

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

Figure by Nils Andersson

★ Superfluid vortices interact/pin to crust lattice

(and to core superconducting flux tubes)

★ Pinning holds up to a critical lag ωcr = (Ωs −Ωc)max

slide-4
SLIDE 4

What could be causing them?

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

IcΩc + Z Ωs(r)dIs = Ltot

★ Two weakly-coupled components ★ Vortices collectively unpin and rearrange

sudden exchange of angular momentum

time spin frequency

Δν{

slide-5
SLIDE 5

time spin down

What could be causing them?

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

Ic ˙ Ωc(t) + Z ˙ Ωs(r, t)dIs = Next

★ Post-glitch relaxation

˙ Ωs depends on lag ω(r,t), nature of interactions, T , ...

★ At a glitch, ω reduces and so does ˙

Ωs

spin-down recovers on local characteristic timescales

{

Δν

.

slide-6
SLIDE 6

Glitch statistics

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

★ Melatos et al. 2008: power-law size distributions

and exponential distributions of waiting times

★ Evidence for scale-invariance

glitches as vortex avalanches events

slide-7
SLIDE 7

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

data from http://www.jb.man.ac.uk/pulsar/glitches.html, thanks to Ben Shaw

slide-8
SLIDE 8

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

data from http://www.jb.man.ac.uk/pulsar/glitches.html, thanks to Ben Shaw

slide-9
SLIDE 9

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

data from http://www.jb.man.ac.uk/pulsar/glitches.html, thanks to Ben Shaw

slide-10
SLIDE 10

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

pulsar # glitches size distribution

J0537-6910 45 normal J0835-4510 (Vela) 19 normal, mixture J1902+0615 6 mixture, normal J1048-5832 6 mixture J2229+6114 6 mixture J1740-3015 35 Weibull, Pareto, lognormal J0534+2200 (Crab) 26 Pareto, Weibull, lognormal J1341-6220 23 Weibull, Pareto, lognormal J0631+1036 15 Pareto, Weibull, lognormal J1801-2304 13 Weibull, mixture J0742-2822 8 Weibull, Pareto, lognormal J1413-6141 7 Weibull, Pareto J0358+5413 6 Weibull, Pareto, lognormal J1825-0935 6 Pareto, Weibull, lognormal J1826-1334 6 Weibull, Pareto J1952+3252 6 Pareto

slide-11
SLIDE 11

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

10 20 30 40 50 60

spin frequency (Hz)

10-14 10-13 10-12 10-11 10-10

spin down rate (Hz/s)

1000 10000 100000 106

age (years)

1012 1013

dipole B-field (Gauss)

★ Distribution type does not appear to correlate with

basic pulsar parameters

★ Individual, well-studied, cases:

J0534+2200 (Crab) J0537-6910

slide-12
SLIDE 12

Glitch size distribution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

10 20 30 40 50 60

spin frequency (Hz)

10-14 10-13 10-12 10-11 10-10

spin down rate (Hz/s)

1000 10000 100000 106

age (years)

1012 1013

dipole B-field (Gauss)

★ Distribution type does not appear to correlate with

basic pulsar parameters

★ Individual, well-studied, cases:

J0534+2200 (Crab) J0537-6910

Crab Crab Crab Crab 0537 0537 0537 0537

slide-13
SLIDE 13

0.1 1 10 0.2 0.4 0.6 0.8 1 Power law Lognormal

Δν (μHz) P (s ≤ Δν)

Crab vs J0537: Glitch sizes

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

★ Power-law size distribution, with lower

cut-off single vortex unpinning ∆νmin >>

★ Trigger: local avalanches involving

billions of vortices (and crustquakes?)


Espinoza et al. 2014

Crab pulsar

Crab pulsar J0537-6910

★ Normal distribution, large glitches ★ Trigger: Threshold-regulated

process depleting almost all angular momentum reservoir

Antonopoulou et al. 2018

slide-14
SLIDE 14

Crab vs J0537: Interglitch time intervals

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

Crab pulsar

  • 3.70

Hz s-1)

0.01 0.1 1 10

Δνg (μHz)

(e)

  • 15

40000 42000 44000 46000 48000 50000 52000 54000 56000

MJD (Days)

  • 0.020

J0537-6910

52000 53000 54000 55000 56000

MJD

10 20 30 40

5 15 25 35 45

Δν (μHz)

★ Unique to J0537: Strong correlation (Δν, Δtpost)

10 20 30 40 50 50 100 150 200 250 300

time to the next glitch (days)

glitch magnitude (µHz)

Antonopoulou et al. 2018

slide-15
SLIDE 15

40000 42000 44000 46000 48000 50000 52000 54000 56000

MJD (Days)

  • 0.025
  • 0.020
  • 0.015
  • 0.010
  • 0.005

δν (10-10 Hz s-1)

  • (b)
  • 3.86
  • 3.84
  • 3.82
  • 3.80
  • 3.78
  • 3.76
  • 3.74
  • 3.72
  • 3.70

1970 1980 1990 2000 2010

Year

ν (10-10 Hz s-1)

  • (a)

Crab vs J0537: Spin down evolution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

Crab pulsar

Lyne et al. 2014

★ Glitches have little impact on the

long-term behaviour

★ Overall braking index n~2.5,

reduces to n~2.3 during period of high glitch activity

★ Between glitches the braking index

is close to its long-term value

time spin down

slide-16
SLIDE 16

52000 53000 54000 55000 56000

  • 199600
  • 199500
  • 199400
  • 199300
  • 199200
  • 199100

MJD [days] ˙ ν [10−15 Hz/s]

Crab vs J0537: Spin down evolution

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

J0537-6910

Antonopoulou et al. 2018

★ Glitches have large impact on the long-term behaviour

★ Long-term n=-1.2 ★ Between glitches n~20

much bigger than its long-term value

40000 42000 44000 46000 48000 50000 52000 54000

MJD

  • 15800
  • 15700
  • 15600
  • 15500

J0537-6910 Vela

★ Similar to Vela pulsar:

★ Long-term n~1.7 ★ Much bigger between

glitches (n>40)

  • 1
  • 1
  • 1

˙ ν [10−15 Hz/s]

slide-17
SLIDE 17

Glitches diversity in other pulsars

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

slide-18
SLIDE 18

Can one model fit all?

Antonopoulou Danai POLNS18 Warsaw, 26/03/2018

★ Dominance of local or global avalanches depending on

critical lag profile (pinning strength, homogeneity, ...), driving rate (spin-down) and temperature

★ Older, lower-B, pulsars (4 objects) tend to have regular

large glitches and inter glitch n >> long-term n

★ Other effects to be accounted for:

magnetic field role relation to magnetosphere thermal effects

}

e.g. magnetars

crustal failure