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Timing analysis of SGR 1627-41. Liang, Jau-Shian Dep. of Physics, NTHU 2004/3/11. Outline. Introduction (1).SGR 1627-41 (2).epoch folding,H-test Data Reduction and Analysis Future work. introduction. 1. The first SGR was observed on March 5, 1979.

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timing analysis of sgr 1627 41

Timing analysis of SGR 1627-41

Liang, Jau-Shian

Dep. of Physics, NTHU

2004/3/11

outline
Outline
  • Introduction

(1).SGR 1627-41

(2).epoch folding,H-test

  • Data Reduction and Analysis
  • Future work
introduction
introduction
  • 1. The first SGR was observed on March 5, 1979.
  • 2. It was discovered some bursts repeated at the same position in 1986.
  • 3. Properties of SGRs

(1)they repeat

(2)soft spectra

(3)short duration

sgr 1627 41
SGR 1627-41
  • First observation:

Ulysses (1998–07-17)

  • RA, DEC SINBAD 16h35m52.00s,-47o35’14.0”J2000

BappoSAX 16h35m49.8s,-47o35’44”J2000

ASCA 16h35m46.41s,-47o35’13.1”J2000

  • associate with nearby SNR : SNR G337.0-0.1
slide8

phases

Phases:

The probability density of phases:

slide10

Epoch folding

If Nj is large, S is approximately distributed as xn-12 for a flat probability density.

slide11

Rayleigh test

If the phase probability density is flat, the displacements are a two-dimensional random walk.

slide12

The means of c and s depend on the Fourier transform sine and cosine amplitudes of f(q).

The Rayleigh power is P=R2/N

==>

The random variabl 2P is therefore approximately distributed as x22.

==>

slide13

Zm2 -test and H-test

A generalization of the Rayleigh test:

Include the effect of a zealous obser in the caculation of significance:

compare fft with epoch folding
Compare FFT with Epoch Folding
  • Epoch folding is more sensitive to the nonsinusoidal pulse shapes characteristics of X-ray pulsars.
  • Epoch folding provides a straightforward approach to handling gaps which routinely appear in data.
  • Epoch folding is extremely time-consuming on the computer.
compare h test with epoch folding
Compare H-test with Epoch Folding
  • Epoch folding is more sensitive to the nonsinusoidal pulse shapes characteristics of X-ray pulsars.
  • The H-test is free of the binning uncertainties associated with epoch folding.
data reduction and analysis
Data Reduction and Analysis

ASCA

1. 57041000 HURLEY 1999-02-06

duration:187.6ks gis:78.4ks sis:72.7ks

BoppoSAX

1. 70821005 Jan van Paradijs 1999-08-08

lecs:34.8ks mecs:80.4ks

2. 70566001 Jan van Paradijs 1998-08-06

lecs:21.3ks mecs:44.9ks

3. 70566002 Jan van Paradijs 1998-09-16

lecs:12ks mecs:30ks

data reduction
Data reduction
  • Use standard screened event file
  • Filtering

Filter region

Filter energy: 1-10kev (21-213)

  • Barycentric correction
slide18
Elevation Angle (ELV) >5
  • Stable Pointing Directions (ACS, ANG_DIST): ACS==0 && ANG_DIST 0 && ANG_DIST <0.01
  • South Atlantic Anomaly (SAA) ==0
  • Cut-off Rigidity (COR)>4 (GeV/c)
  • (G2_H0+G2_H2+G3_H0+G3_H2)<45 && (G2_H0+G2_H2+G3_H0+G3_H2)<0.45*COR**2-13*COR+125 && RBM_CONT <100
slide20
The recommended region filter radius for bright sources in the GIS is 6 arcmin (24 pixels).
  • For weak sources smaller regions could be used to reduce the background.
slide21

gis2

ra=16h35m46.41s

dec=-47o35’13”.1

Radius=4’

Ntotal=48.8k

Nreg=2355

slide22

gis3

ra=16h35m46.41s

dec=-47o35’13”.1

Radius=4’

Ntotal=51.4k

Nreg=3017

data reduction bapposax
Data reduction(BappoSAX)
  • Merging of MECS units:MECS2, MECS3 > MECS23
  • Filtering

Filter time : GTI_XY.fits

Filter region

Filter energy: 2-10kev (43-215)

  • Barycentric correction
slide24

70566001

Ra=16h35m49.8s

dec=-47o35’44”

Radius=4’

Ntotal=49.9k

Nreg=2359

slide25

70566002

Ra=16h35m49.8s

dec=-47o35’44”

Radius=4’

Ntotal=27.3k

Nreg=1340

slide26

70566005

Ra=16h35m49.8s

dec=-47o35’44”

Radius=4’

Ntotal=65.3k

Nreg=2409

use efsearch to detect signal in a large range of period
Use efsearch to detect signal in a large range of period
  • Data: ASCA gis2 & gis3
  • Range of period: 1-1000 s
  • Resolution: p*p/T/10, T=138600 s
  • Total tries: 1323k tries
slide31

Data:SAX 70566001, 70566002, 70821005

  • Range of period: 1-1000 s
  • Resolution: p*p/T/10
  • Total tries:

70566001 887k tries T=85634

70566002 651k tries T=62376

70821005 1662k tries T=163642

use h test to detect signal in a large range of period
Use H-test to detect signal in a large range of period
  • Data:SAX 70566001, 70566002, 70821005 Range of period: 1-1000 s
  • Resolution: p*p/T/10,
future work
Future work
  • Combine more data: XTE data
  • Search other range of period: 0.01-1 s
  • Estimate upper limit
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