1. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Prompt Emission Properties of X-ray Flashes and Gamma-ray Bursts T. Sakamoto (CRESST/UMBC/GSFC)

2. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Contents 1.First BAT GRB catalog 2.X-ray Flashes (XRFs) 3.Prompt emission properties of XRFs (BATSE/BeppoSAX/HETE-2/Swift)? (4. X-ray flares) (5. X-ray afterglows of XRFs)

3. Swift 2008. 6. 25. 2008 Nanjing GRB Conference First BAT GRB catalog (BAT1 catalog) Sakamoto et al. ApJS, 175, 179

4. Swift 2008. 6. 25. 2008 Nanjing GRB Conference BAT GRB sky map BAT GRB sky map - 237 GRBs (from GRB 041217 to GRB 070616) - BAT event-by-event data analysis Galactic coordinate

5. Swift 2008. 6. 25. 2008 Nanjing GRB Conference T 90 /T 50 (mask-weighted 15-350 keV)

6. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Hardness – T 90

7. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Time-averaged spectrum (PL fit)

8. Swift 2008. 6. 25. 2008 Nanjing GRB Conference PL photon index vs. P(15-150 keV)

9. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Summary (I) BAT is fine. Detecting/localizing ~100 GRBs/yr. Watching for z>7 and z<0.1 GRBs. Watching for the next naked eye burst.

10. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray Flashes (XRFs)

11. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray band  ray band X-ray flash (XRF) Classical gamma-ray burst (C-GRB) (Heise et al. 2001) (in’t Zand et al. 1999) X-ray flashes and classical (long) GRBs : BeppoSAX/BATSE

12. Swift 2008. 6. 25. 2008 Nanjing GRB Conference XRF 010213 GRB 030725 X-ray flashes and classical (long) GRBs : HETE-2

13. Swift 2008. 6. 25. 2008 Nanjing GRB Conference GRB 050401 XRF 050416A X-ray flashes and classical (long) GRBs: Swift BAT

14. Swift 2008. 6. 25. 2008 Nanjing GRB Conference “X-ray Flashes”

15. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Empirical spectral models of GRBs E  exp (  E/E 0 ) EE E 0 = E peak / (2 +  ) E break = (  E 0 Band function dN/dE Energy (Band et al. 1993)

16. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Spectral parameters of GRBs (BATSE) Band function  EpEp  3  2  1 0 1 200 150 100 50 0 1 2 3 4 log E p [keV] (  ~  2.5) 150 100 50 0 (BATSE spectral catalog, Preece et at. 2000) Energy F E EpEp E  200 – 300 keV

17. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-Ray Flashes (XRFs) and X-ray rich GRBs (Ginga and BeppoSAX WFC) Ginga (Strohmayer et al. 1998)  1 0 1 2  1 2 3 4 log E p [keV] 0 1 2 3 4 0 2 4 Number of events BATSE WFC / BATSE (Kippen et al. 2002) (22 GRBs) 10 100 1000 E p (keV) Peak Flux P 1024 (ph cm -2 s -1 ) XRFs: Systematically low E peak

18. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Prompt emission properties of XRFs

19. Swift 2008. 6. 25. 2008 Nanjing GRB ConferenceObjective GRBs Classify XRFsXRRsC-GRBs (X-ray flashes) (X-ray-rich GRBs) (Classical GRBs) Spectral hardness XRFs XRRs C-GRBs XRFs XRRs C-GRBs

20. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Classification of GRBs (Fluence in 2-30 keV : S X, Fluence in 30-400 keV : S   log (S X / S  ) > 0  0.5 < log (S X / S  ) ≤ 0 log (S X / S  ) ≤  0.5 XRF XRR C-GRB (Sakamoto et al. 2005) HETE-2 BeppoSAX “XRFs: Detected by Wide Field Camera (WFC), but not by Gamma-Ray Burst Monitor (GRBM)” Swift/BAT ?

21. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak vs. fluence ratio 1 10100 1000 E peak (keV) 0.1 1 10 S X / S  XRF XRR C-GRB HETE GRB sample

22. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Classification of GRBs (Fluence in 2-30 keV : S X, Fluence in 30-400 keV : S   log (S X / S  ) > 0  0.5 < log (S X / S  ) ≤ 0 log (S X / S  ) ≤  0.5 XRF XRR C-GRB (Sakamoto et al. 2005) HETE-2 BeppoSAX “XRFs: Detected by Wide Field Camera (WFC), but not by Gamma-ray burst monitor (GRBM)” Swift/BAT  Ep=30 keV  Ep=100 keV (Sakamoto et al. 2008)

23. Swift 2008. 6. 25. 2008 Nanjing GRB Conference GRB sample BATSE (Kaneko et al. 2006) - Time-averaged best fit spectral parameters by BAND and COMP fit 0 XRF 181 GRB 26 XRR 155 C-GRB Total 568 GRBs (342 GRBs) BeppoSAX (D’Alessio et al. 2006, Amati et al. 2002) - Only  Ep information 7 XRF 24 GRB 11 XRR 6 C-GRB HETE-2 (Sakamoto et al. 2005; Pelangeon et al. submitted A&A) 26 XRF 84 GRB 33 XRR 25 C-GRB Swift/BAT (Sakamoto et al. 2008+); 17 XRF 279 GRB 179 XRR 83 C-GRB Swift/BAT with Ep (Sakamoto et al. 2008+); 17 XRF 53 GRB 22 XRR 14 C-GRB

24. Swift 2008. 6. 25. 2008 Nanjing GRB Conference List of XRFs I (BeppoSAX/HETE-2/Swift) XRF Mission E peak obs [keV] AG z 971019 SAX 19 +/- 1 - - 990520 SAX 26 +/- 3 X - 990526 SAX 15 +/-14 - - 990704 SAX 9 (-7/+50) X - 000206 SAX 38 +/- 5 - - 000416 SAX 1.6 +/- 6.6 - - 010213 HETE-2 3.4 +- 0.4 - - 010225 HETE-2 32 (+27/-9) - - 011019 HETE-2 19 (+18/-9) - - 011130 HETE-2 < 4 - - 011212 HETE-2 NA - - 020317 HETE-2 28 (+13/-7) - - 020427 SAX 3 +/- 3 X - 020625 HETE-2 9 (+5/-3) - - 020903 HETE-2 3 +/- 1 O,R 0.25 021021 HETE-2 15 (+14/-7) - - 021104 HETE-2 28 (+17/-8) - - XRF Mission E peak obs [keV] AG z 030416 HETE-2 3 (+1/-2) - - 030429 HETE-2 35 (+12/-8) O 2.65 030528 HETE-2 32 +/- 5 X,O 0.782 030723 HETE-2 < 8.9 X,O - 030823 HETE-2 27 (+7/-5) - - 030824 HETE-2 6.1 (+2/-4) - - 031109B HETE-2 38 (+28/-12) - - 031111B HETE-2 6 (+4/-5) - - 040423 HETE-2 30 (+5/-4) - - 040701 HETE-2 < 3.4 X - 040825B HETE-2 25 (+16/-8) - - 040912A HETE-2 14 (+3/-4) - - 040912B HETE-2 17 (+13/-13) X 1.563 040916 HETE-2 < 3.5 O - 050406 Swift 29 (+7/-12) X,O 050408 HETE-2 26 (+11/-7) X,O 1.2357 050416A Swift 17 (+6/-10) X,O,R 0.6535

25. Swift 2008. 6. 25. 2008 Nanjing GRB Conference List of XRFs II (BeppoSAX/HETE-2/Swift) XRF Mission E peak obs [keV] AG z 050509 HETE-2 < 19 - - 050714B Swift 27 (+7/-18) X - 050819 Swift 22 (+6/-17) X - 050824 Swift < 19 X,O 0.83 060218 Swift 4.7 (-0.3/+0.4) X,O,R 0.0331 060219 Swift < 33 X - 060428B Swift 23 (+5/-12) X,O - 060512 Swift 23 (+8/-18) X,O 0.4428 060923B Swift < 27.6 X - 060926 Swift < 23 X,O 3.20 061218 Swift 19 (+11/-8) - - 070224 Swift < 35 X,O - 070714A Swift < 20 X - 070721A Swift < 30 X,O - 080218B Swift 20 (+5/-6) - - 080330 Swift < 24 X,O 1.51 080515 Swift 24 (+5/-5) X,O - Total: 51 XRFs XA : 24 XRFs OA : 17 XRFs z : 11 XRFs

26. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Histogram of log[S(2-30 keV)/S(30-400 keV)] C-GRBs XRRXRF

27. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Histogram of S(25-50 keV)/S(50-100 keV) C-GRBs XRRXRF Broad continuum in the fluence distribution

28. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(2-30 keV) vs. S(30-400 keV) C-GRBs/XRR XRR/XRF

29. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(2-30 keV) vs. S(30-400 keV) C-GRBs/XRR XRR/XRF

30. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(25-50 keV) vs. S(50-100 keV) C-GRBs/XRR XRR/XRF

31. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(25-50 keV) vs. S(50-100 keV) C-GRBs/XRR XRR/XRF

32. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(25-50 keV) vs. S(50-100 keV) C-GRBs/XRR XRR/XRF Single distribution in the fluence-fluence plane

33. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Histogram of E peak obs Broad E peak obs distribution (from a few keV to a few MeV)

34. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. alpha

35. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. alpha

36. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. alpha

37. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. alpha alpha ~ -1 for all GRBs

38. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. beta

39. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. beta

40. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. beta

41. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. beta beta ~ -2.5 for all GRBs

42. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. S(2-400 keV)

43. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. S(2-400 keV)

44. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. S(15-150 keV)

45. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. S(15-150 keV)

46. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak obs vs. S(15-150 keV) Positive correlation between E peak obs and the fluence E peak obs ~ S 0.5

47. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Redshift distributions

48. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak src distribution Broad E peak src distribution

49. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak -E iso relation E peak src = 95 keV (E iso /10 52 ergs) 0.5 (Amati 2006)

50. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Re-classify XRFs at the rest frame XRF z E peak obs E peak src Re-classification 020930 0.25 2.6 3.3 XRF 030429 2.65 35 128 C-GRBs 030528 0.782 32 57 XRR 040912B 1.563 17 44 XRR 050408 1.236 26 58 XRR 050416A 0.654 17 28 XRF 050824 0.83 <19 <34 XRF/XRR 060218 0.0331 4.7 4.9 XRF 060512 0.443 23 33 XRR 060926 3.20 <23 <97 XRR 080330 1.51 <24 <60 XRR Only three XRFs cab be classified as XRF at the rest frame.

51. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Summary (II) XRFs, XRRs, and GRBs form a continuum (BATSE/BeppoSAX/HETE-2/Swift). E peak obs is broadly distributed from a few keV to a few MeV (same for E peak src ). The redshift distribution of XRFs could be systematically lower than C-GRBs. We only have three samples of intrinsic XRFs. C-GRB XRR XRF E -1 E- 2.5 E peak

52. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray Flares

53. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray Flare: Prompt X-ray emission GRB 720427 (Metzger et al, 1974) (Apollo 16 and Vela 6A) GRB 030725

54. Swift 2008. 6. 25. 2008 Nanjing GRB Conference GRB 080607 X-ray flare Counts/sec/det Counts/sec Counts/sec/wire

55. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Late-time X-ray flares are unique… (Watson et al. 2005) X-ray flares T 0 > 1000 s Very unique Swift/XRT observations However… X-ray flares T 0 < 1000 s Same prompt X-ray emission observed by previous missions (e.g. HETE-2/WXM) GRB 050904

56. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray afterglows of XRFs (Sakamoto et al. 2008, ApJ, 679, 570)

57. Swift 2008. 6. 25. 2008 Nanjing GRB Conference XRF X-ray afterglow

58. Swift 2008. 6. 25. 2008 Nanjing GRB Conference C-GRB X-ray afterglow

59. Swift 2008. 6. 25. 2008 Nanjing GRB Conference X-ray light curve at the rest-frame E peak src < 100 keV 100 keV < E peak src < 300 keV E peak src > 300 keV

60. Swift 2008. 6. 25. 2008 Nanjing GRB Conference FxFx Time [s] t –0.5 – t –1.0 t -1.0 – t-2.0 t -1 C-GRB XRF 10 3 -10 4 sec C-GRB: Break around 10 3 -10 4 sec XRF: Simple decay with the index of -1 Flux is systematically lower Must be telling something…

61. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Summary (III) XRFs, XRRs, and GRBs form a continuum (BATSE/BeppoSAX/HETE-2/Swift). E peak obs is broadly distributed from a few keV to a few MeV (same for E peak src ). The redshift distribution of XRFs could be systematically lower than C-GRBs. We only have three samples of intrinsic XRFs. Clear definition in “X-ray flare” is needed. Distinct difference in X-ray afterglows between XRFs and C-GRBs.

62. Swift 2008. 6. 25. 2008 Nanjing GRB Conference

63. Swift 2008. 6. 25. 2008 Nanjing GRB Conference

64. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak vs. Energy Flux Number of simulated spectra      Band –    PL ) > 6 BAT 15-150 keV E peak measurement with BAT: > ~ 2 x 10 -8 ergs/cm 2 /s (log F(15-150) = -7.7)

65. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak -Gamma relation

66. Swift 2008. 6. 25. 2008 Nanjing GRB Conference E peak -Gamma relation

67. Swift 2008. 6. 25. 2008 Nanjing GRB Conference BAT (81 GRBs) BATSE BAT T 90 vs. Hardness

68. Swift 2008. 6. 25. 2008 Nanjing GRB Conference GRB 020531 GRB 050709 Sakamoto et al. Villasenor et al. HETE (46 GRBs) BATSE HETE T 90 vs. Hardness

69. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Konus-Wind T 90 vs. Hardness Mazets et al. : short GRBs V. Pal’shin : long GRBs Konus-Wind (125 GRBs) BATSE

70. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Konus-Wind Histograms of Hardness long GRBs (T 90  2 sec.) Short GRBs (T 90 < 2 sec.) HR ≧ 6: 10% short GRBs (46% BATSE) HR ≧ 8: 0% short GRBs (26% BATSE) S(100-300 keV) / S(50-100 keV) Number of GRBs

71. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Histogram of Hardness - Short GRBs - S(100-300 keV) / S(50-100 keV) Number of GRBs BAT HETE BATSE Konus-Wind

72. Swift 2008. 6. 25. 2008 Nanjing GRB Conference  vs. E 0  vs. E 0  E 0 [keV] 4-66-8 8-10 Hardness = S(100-300 keV) S(50-100 keV)

73. Swift 2008. 6. 25. 2008 Nanjing GRB Conference S(2-30 keV) vs. S(30-400 keV)

74. Swift 2008. 6. 25. 2008 Nanjing GRB Conference “Short XRFs” in the Swift sample?

75. Swift 2008. 6. 25. 2008 Nanjing GRB Conference “Short XRFs” in the Swift sample?

76. Swift 2008. 6. 25. 2008 Nanjing GRB Conference “Short XRFs” in the Swift sample?

77. Swift 2008. 6. 25. 2008 Nanjing GRB Conference “Short XRFs” in the Swift sample?

78. Swift 2008. 6. 25. 2008 Nanjing GRB Conference How to make short XRF with BAT? dN/dE E E -1 E -2.3 Ep Flux (15-150 keV) Input light curve Ep = 50 keV Ep = 30 keV Ep = 20 keV Count rate [c/s] - BAT energy response (30 deg) - background included - Xspec fakeit “Shortness” of BAT XRF is very likely due to the instrumental effect.

79. Swift 2008. 6. 25. 2008 Nanjing GRB Conference XRF XRR C-GRB Energy spectrum of XRFs 110100 1000 Energy (keV) 10 2 1 10  2 10  4 F  (keV cm  2 s  1 )

80. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Discussion (1) Two categories in the luminosity evolution in the optical light curves (Liang & Zhang). = 96 keV for the dim group = 543 keV for the bright group (ref Amati 2006) Consistent with the X-ray luminosity light curves Understanding Shallow-to-normal break in the geometrical jet model.

81. Swift 2008. 6. 25. 2008 Nanjing GRB Conference Discussion (2) Shallow-to-normal break E peak Thick ring jet model