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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

24167 results found.

  1. GRB050126: Burst Parameters Measured by BAT
  2. GRB 050126: Prompt XRT detection and localization
  3. GRB 050124 I-band observation
  4. GRB050124,optical observation
  5. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  6. GRB050124: Refined BAT position, spectral and fluence information
  7. GRB050124: Swift-BAT position of a double-peaked burst
  8. GRB050123,optical observation
  9. GRB 050123: KAIT observations
  10. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  11. GRB050117a: Refined analysis
  12. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  13. GRB050117b: Swift-BAT detection of a weak burst
  14. GRB 050117, I-band observations
  15. GRB050117: Swift-BAT detection of a long multi-peaked burst
  16. GRB050117: Swift XRT Position
  17. SGR1806-20: Swift-BAT observations of two additional bursts
  18. SGR 1806-20, RHESSI observations of the 041227 giant flare
  19. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  20. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  21. The giant outburst from SGR 1806-20
  22. GRB041228: Swift-BAT detection of a burst
  23. GRB041219; RXTE ASM Observations
  24. NIR Observations of GRB 041219
  25. GRB041226: Swift-BAT detection of a burst
  26. GRB 041224: near-infrared observations with REM
  27. GRB 041223 Fluence measured by Swift-BAT
  28. GRB041224: Swift-BAT detection of a soft burst
  29. Swift-BAT Time History of GRB041219
  30. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  31. GRB041223: Swift-BAT detection of a bright long burst
  32. GRB041220: Swift-BAT burst
  33. Deep RAPTOR observations during GRB 041219
  34. GRB041219c: Third Burst in One Day from Swift-BAT
  35. GRB041219b: A Swift-BAT burst
  36. GRB 041219 ,optical observation
  37. GRB 041218: R-band optical observations
  38. Swift-BAT detection of the bright long burst GRB041219
  39. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  40. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  41. GRB041217: The First GRB Located On-Board Swift
  42. GRB041211: RAPTOR observations
  43. GRB041211, BVRcIc field calibration
  44. GRB041211,optical observation
  45. GRB 041211: KAIT observations
  46. Distribution of IBAS Alerts for NON-GRB sources
  47. GRB 041006: GETS Optical Afterglow Observation
  48. Summary of the recent bursts from SGR 1806-20
  49. GRB041015, optical observation in CrAO
  50. Bright bursts from SGR1806-20
  51. GRB 041016: BOOTES-2 simultaneous observation
  52. GRB041016,optical observation
  53. GRB 041016: Optical limits
  54. GRB 041016:Optical limit during first minute
  55. GRB041016: MASTER: Optical observations
  56. GRB041006: Near Infrared observations
  57. GRB 041016: Optical limit
  58. GRB 041015 R band observations
  59. GRB040924, BVRcIc field calibration
  60. GRB041015: MASTER: Optical observations
  61. GRB041015,optical observation
  62. GRB041006: MASTER optical observations
  63. GRB041006,optical observation
  64. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  65. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  66. GRB040929,optical observation
  67. GRB040924,optical observation
  68. GRB040924: KAIT observations
  69. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  70. GRB040924 (H3564): Optical afterglow candidate
  71. XRF040912, BVRcIc field calibration
  72. XRF040916, BVRcIc field calibration
  73. GRB040916: Optical observations
  74. GRB/XRF040912,optical observations
  75. GRB 040912, BVRI observations
  76. Optical observations of field of GRB040912
  77. HETE 3557: Optical observations
  78. GRB040825B, BVRcIc field photometry
  79. GRB040825A, BVRcIc field photometry
  80. GCN GRB OBSERBATION REPORT
  81. GRB 040825A,optical observations
  82. Increase of SGR 1806-20 activity
  83. GRB040825A: optical observations
  84. GRB040825B: optical observations
  85. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  86. GRB 040825A: Optical observations.
  87. MASTER: GRB040825b optical observation
  88. GRB040825B: Correction to GCN 2657
  89. GRB 040812: Second epoch CXO Observations
  90. GRB040823,optical observation
  91. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  92. CXO observation of GRB 040812
  93. Ongoing activity of SGR 1806-20
  94. GRB040709 J,H-band observations
  95. GRB040706:observation at University of Miyazaki
  96. GRB 040606: Optical observations
  97. MASTER: HETE Alert 3274 optical observation
  98. Activivty of SGR 1806-20
  99. GRB 040511: Optical limit
  100. GRB 040511: ROTSE-III Rapid Optical Upper Limits

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