臺灣博碩士論文加值系統

Soft gamma repeaters (SGRs) 與 Anomalous X-ray Pulsars(AXPs)目前被認為是一種超強磁場的中子星，稱之為"magnetars"。除了SGR 1627-41，所有的已確認的SGR與AXP都已經被發現自轉週期。我們使用BeppoSAX、ASCA與RXTE等人造衛星的觀測資料進行分析尋找可能的週期，並在此呈現我的結果。我們使用H-test與epoch folding兩種分析方法，以五分之一的傅立葉寬度為一個搜尋步伐，從0.01秒搜尋至100秒。我們在1998年八月BeppoSAX的觀測資料中發現五個可疑的週期，一個在0.019秒，而其餘分布在6秒至98秒之間。這些可疑的週期並未在其他的觀測資料中發現。未來若欲深入研究這些可疑的週期將需要更多的觀測資料，特別是在SGR 1627-41處於較高亮度時期的觀測資料。

Soft gamma repeaters (SGRs) and Anomalous X-ray Pulsars(AXPs) are regarded as the so called "magnetars", which are strongly magnetized neutron star. All spin-down period of the identified SGRs and AXPs have been found, except for SGR 1627-41. We present the results of periodicity search
in the X-ray data of SGR 1627-41 observed by the BeppoSAX, ASCA and RXTE missions. Searches have been performed with the H-test and the method of epoch folding in the period range between 0.01 sec and 100 sec with period steps corresponding to one fifth of the Fourier width. We have found 5 significant periods in the 1998 August BeppoSAX observation. One of these features is at 0.019 sec, and the others are between 6 sec and 98 sec. These features are not found in later observations, during which the source flux was lower. To further investigate to verify of these periods, more observations, particularly during when will the source be in high state of the source, will be very helpful.

1 Introduction 3
1.1 SGR . . . . . . . . . . . . . . . . . . . . . 3
1.2 The magnetar model . . . . . . . . . . . . . 5
1.3 SGR 1627-41 . . . . . . . . . . . . . . . . . 7
1.4 Motivation . . . . . . . . . . . . . . . . . 9
2 Observations and data reduction 10
2.1 Observation . . . . . . . . . . . . . . . . . 10
2.1.1 BeppoSAX Observation . . . . . . . . . . . 11
2.1.2 ASCA Observation . . . . . . . . . . . . . 13
2.1.3 RXTE Observation . . . . . . . . . . . . . 15
2.2 Data Reduction . . . . . . . . . . . . . . . 17
2.2.1 Data reduction for BeppoSAX data . . . . . 18
2.2.2 Data reduction for ASCA data . . . . . . . 18
2.2.3 Data reduction for RXTE data . . . . . . . 20
3 The methods for timing analysis 22
3.1 Epoch-folding . . . . . . . . . . . . . . . . 22
3.2 H-test . . . . . . . . . . . . . . . . . . . 23
4 Results and discussion 25
4.1 The procedure of searching periods . . . . . 25
4.2 Possible signatures in the H-test . . . . . . 26
4.3 Discussion . . . . . . . .. . . . . . . . . . 31

[1] Aptekar, R.L. et al., 2001, ApJS. 137, 227
[2] De Jager, et al. 1989, A&A, 221, 180
[3] Fishman, G.J., Meegan, C., 1995, A&A, 33, 415
[4] GÄo·gÄu»s, E. et al., 2001, ApJ, 558, 228
[5] GÄo·gÄu»s, E. et al., 1999, ApJ, 526, L93
[6] GÄo·gÄu»s, E. et al., 2002, ApJ, 577, 929
[7] Gotthelf, E. V. et al., 1999, ApJ, 522, L49
[8] Hurley, K., et al. 1999, ApJ, 510, L111
[9] Hurley, K., et al. 1999a, Nature, 397, 41
[10] Hurley, K., 2000, AIPC, 510, 515
[11] Hurley, K., et al. 2000, ApJ, 528, L21
[12] Ioka, K. 2001, MNRAS, 327, 639
[13] Israel, G. L. etal., 1999, ApJ, 518, L107
[14] Kaspi, V., et al., 1999, ApJ, 525,L33
[15] Kaspi, V., et al. 2003, ApJ, 588, L93
[16] Kouveliotou, C., et al. 1998a, Nature, 393, 235
[17] Kouveliotou, C., et al., 1998b, IAU Circ. 6944
[18] Kouveliotou, C., et al., 1999, ApJ, 510, L115
[19] Kouveliotou, C., et al. 2003, ApJ, 596, L79
[20] Kulkarni, S., et al. 2003, ApJ, 585, 948
[21] Leahy D. A., 1987, A&A, 180, 275
[22] Marsden1, D., & White, N., 2001, ApJ, 551, L155
[23] Mazets, E.P., et al., 1979, Nature, 282, 587V589
[24] Mereghetti, S. 2000, in The Neutron StarVBlack Hole Connection, ed.
C. Kouveliotou, J. Ventura, E. van den Heuvel (NATO ASI Ser. C, 567;
Dordrecht: Kluwer), 351
[25] Murakami, T., et al., 1999, ApJ, 510, L119
[26] Paul, B. et al., 2000, ApJ, 537, 319
[27] Rothschild, R.E., et al., 1994, Nature, 368, 432
[28] Thompson, C., Duncan, R. 1995, MNRAS, 275, 255
[29] Thompson, C., Duncan, R.1996, ApJ, 473, 322
[30] Woods, P., et al. 1999, ApJ, 519, L139
[31] Woods, P. M., et al., 2000, ApJ, 535, L55
[32] Woods, P.M., et al., 2001, ApJ, 552, 748
[33] Woods, P.M., et al., 2002, ApJ 576, 381
[34] Woods, P., 2003, AdSpR, 33, 645