Timing analysis of SGR 1627-41

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Timing analysis of SGR 1627-41

• Liang, Jau-Shian
• Dep. of Physics, NTHU
• 2004/3/11

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Outline

• Introduction
• (1).SGR 1627-41
• (2).epoch folding,H-test
• Data Reduction and Analysis
• Future work

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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

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SGR first giant P(s) quiescence P(s) P super-Eddington observe flare? (erg/s) (10-11s/s) burst
1806 1900 0526 1627 1801 1979 no ?? 21035 7.74 2.8 103X 1979 yes 5.16 31034 5.16 6.1 103X 1979 yes 8 1036 ?? ?? 2104X 1998 no ?? 1035 ?? ?? 4105X 1997 no ?? ?? ?? ?? ??
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SGR 1627-41

• First observation
• Ulysses (199807-17)
• RA, DEC
  SINBAD 16h35m52.00s, -47o3514.0
  J2000
• BappoSAX 16h35m49.8s, -47o3544 J2000
• ASCA 16h35m46.41s, -47o3513.1
  J2000
• associate with nearby SNR
  SNR G337.0-0.1

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phases
Phases
The probability density of phases
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Epoch folding
If Nj is large, S is approximately distributed as
xn-12 for a flat probability density.
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Rayleigh test
If the phase probability density is flat, the
displacements are a two-dimensional random walk.
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The means of c and s depend on the Fourier
transform sine and cosine amplitudes of f(q).
The Rayleigh power is PR2/N
gt
The random variabl 2P is therefore approximately
distributed as x22.
gt
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Zm2 -test and H-test
A generalization of the Rayleigh test
Include the effect of a zealous obser in the
caculation of significance
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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.

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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.

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Data Reduction and Analysis

• ASCA
• 1. 57041000 HURLEY 1999-02-06
• duration187.6ks gis78.4ks sis72.7ks
• BoppoSAX
• 1. 70821005 Jan van Paradijs 1999-08-08
• lecs34.8ks mecs80.4ks
• 2. 70566001 Jan van Paradijs 1998-08-06
• lecs21.3ks mecs44.9ks
• 3. 70566002 Jan van Paradijs 1998-09-16
• lecs12ks mecs30ks

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Data reduction

• Use standard screened event file
• Filtering
• Filter region
• Filter energy 1-10kev (21-213)
• Barycentric correction

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• Elevation Angle (ELV) gt5
• Stable Pointing Directions (ACS, ANG_DIST)
  ACS0 ANG_DIST 0 ANG_DIST lt0.01
• South Atlantic Anomaly (SAA) 0
• Cut-off Rigidity (COR)gt4 (GeV/c)
• (G2_H0G2_H2G3_H0G3_H2)lt45
  (G2_H0G2_H2G3_H0G3_H2)lt0.45COR2-13COR125
  RBM_CONT lt100

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• 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.

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gis2 ra16h35m46.41s dec-47o3513.1 Radius4 Nt
otal48.8k Nreg2355
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gis3 ra16h35m46.41s dec-47o3513.1 Radius4 Nt
otal51.4k Nreg3017
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Data reduction(BappoSAX)

• Merging of MECS units MECS2, MECS3 gt MECS23
• Filtering
• Filter time GTI_XY.fits
• Filter region
• Filter energy 2-10kev (43-215)
• Barycentric correction

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70566001 Ra16h35m49.8s dec-47o3544
Radius4 Ntotal49.9k Nreg2359
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70566002 Ra16h35m49.8s dec-47o3544
Radius4 Ntotal27.3k Nreg1340
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70566005 Ra16h35m49.8s dec-47o3544
Radius4 Ntotal65.3k Nreg2409
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Use efsearch to detect signal in a large range of
period

• Data ASCA gis2 gis3
• Range of period 1-1000 s
• Resolution pp/T/10, T138600 s
• Total tries 1323k tries

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• DataSAX 70566001, 70566002, 70821005
• Range of period 1-1000 s
• Resolution pp/T/10
• Total tries
• 70566001 887k tries T85634
• 70566002 651k tries T62376
• 70821005 1662k tries T163642

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Use H-test to detect signal in a large range of
period

• DataSAX 70566001, 70566002, 70821005 Range of
  period 1-1000 s
• Resolution pp/T/10,

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Future work

• Combine more data XTE data
• Search other range of period 0.01-1 s
• Estimate upper limit