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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. 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

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  1. Timing analysis of SGR 1627-41 Liang, Jau-Shian Dep. of Physics, NTHU 2004/3/11

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

  3. 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

  4. 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

  5. phases Phases: The probability density of phases:

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

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

  8. 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. ==>

  9. Zm2 -test and H-test A generalization of the Rayleigh test: Include the effect of a zealous obser in the caculation of significance:

  10. 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.

  11. 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.

  12. 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

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

  14. 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

  15. 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.

  16. gis2 ra=16h35m46.41s dec=-47o35’13”.1 Radius=4’ Ntotal=48.8k Nreg=2355

  17. gis3 ra=16h35m46.41s dec=-47o35’13”.1 Radius=4’ Ntotal=51.4k Nreg=3017

  18. 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

  19. 70566001 Ra=16h35m49.8s dec=-47o35’44” Radius=4’ Ntotal=49.9k Nreg=2359

  20. 70566002 Ra=16h35m49.8s dec=-47o35’44” Radius=4’ Ntotal=27.3k Nreg=1340

  21. 70566005 Ra=16h35m49.8s dec=-47o35’44” Radius=4’ Ntotal=65.3k Nreg=2409

  22. 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

  23. 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

  24. 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,

  25. Future work • Combine more data: XTE data • Search other range of period: 0.01-1 s • Estimate upper limit

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