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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"

27418 results found.

  1. GRB 050306: CORRECTION to date of observation
  2. GRB 050306: No Swift UVOT Optical Counterpart Detected
  3. GRB 050306: Possible X-ray Afterglow Position from the Swift
  4. Swift trigger 107518: optical observation
  5. GRB 050306,optical observation
  6. GRB 050306: Swift-BAT detection of a long burst
  7. Ongoing activity of SGR 1806-20 after the giant flare
  8. GRB 050219b: candidate NIR afterglow
  9. Confirmed XRF nature for GRB050215b
  10. GRB 050223: optical observations
  11. GRB050223: No Swift UVOT Detection of Afterglow Emission
  12. GRB050223: ROTSE-III Optical Observations
  13. GRB 050223 Swift/BAT detection of a burst
  14. GRB 050223: Swift XRT Position
  15. GRB050219b: CORRECTION to time of UVOT observations
  16. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  17. GRB050219b: No Swift UVOT Detection of Afterglow Emission
  18. GRB 050219b: Swift-BAT detection of a burst
  19. GRB 050219b: CORRECTION: Swift XRT Position
  20. GRB 050219b: Swift XRT Position
  21. GRB 050219a, optical observations
  22. GRB 050219a: Refined XRT position
  23. GRB050219a: No Swift UVOT Detection of Afterglow Emission
  24. GRB 050219: Swift-BAT detection of a burst
  25. GRB050215b: Swift UVOT Detection of Afterglow Emission
  26. GRB 050219: Prompt X-ray position
  27. GRB 050215B: candidate afterglow
  28. GRB 050215b : Lulin follow-up observation
  29. GRB 050215b, BOOTES-2 simultaneous optical observations
  30. GRB 050215B: UKIRT K-band imaging
  31. GRB 050215b: Swift XRT Observations
  32. GRB050215b: No Swift UVOT Detection of Afterglow Emission
  33. GRB050215a: No Swift UVOT Detection of Afterglow Emission
  34. Swift-BAT detects two bursts: GRB050215a and GRB050215b
  35. GRB 050215b, BOOTES-1B optical limit
  36. GRB050215B: ROTSE-III optical observations
  37. GRB050215A: ROTSE-III Optical Observations
  38. GRB050209: REM optical observations
  39. GRB 050209 Optical observations
  40. GRB050209: P60 Optical Observations
  41. GRB 050209: Optical observation
  42. Further analysis of the short Swift-BAT GRB 050202
  43. GRB 050202: Second epoch radio observations
  44. GRB050202: Radio Observations
  45. GRB 050202: Short burst detected by Swift-BAT
  46. SGR1806-20: Swift-BAT detection of a large normal burst
  47. GRB050128: Faulkes Telescope South observations
  48. GRB050128,optical observations
  49. GRB050128 Swift-BAT observations
  50. GRB 050128: Swift XRT prompt afterglow position
  51. GRB050126: MASTER optical limit for KECK OT
  52. GRB050126: Burst Parameters Measured by BAT
  53. GRB 050126: Prompt XRT detection and localization
  54. GRB 050124 I-band observation
  55. GRB050124,optical observation
  56. GRB 050124: Swift XRT Detection of X-ray Afterglow Emission
  57. GRB050124: Refined BAT position, spectral and fluence information
  58. GRB050124: Swift-BAT position of a double-peaked burst
  59. GRB050123,optical observation
  60. GRB 050123: KAIT observations
  61. GRB 050123(=H3666): A GRB Localized in Real Time by HETE
  62. GRB050117a: Refined analysis
  63. GRB 041224 and GRB 041226: BOOTES-2 simultaneous observations
  64. GRB050117b: Swift-BAT detection of a weak burst
  65. GRB 050117, I-band observations
  66. GRB050117: Swift-BAT detection of a long multi-peaked burst
  67. GRB050117: Swift XRT Position
  68. SGR1806-20: Swift-BAT observations of two additional bursts
  69. SGR 1806-20, RHESSI observations of the 041227 giant flare
  70. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  71. SGR1806-20: Swift-BAT observation of the 041227 super-flare
  72. The giant outburst from SGR 1806-20
  73. GRB041228: Swift-BAT detection of a burst
  74. GRB041219; RXTE ASM Observations
  75. NIR Observations of GRB 041219
  76. GRB041226: Swift-BAT detection of a burst
  77. GRB 041224: near-infrared observations with REM
  78. GRB 041223 Fluence measured by Swift-BAT
  79. GRB041224: Swift-BAT detection of a soft burst
  80. Swift-BAT Time History of GRB041219
  81. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  82. GRB041223: Swift-BAT detection of a bright long burst
  83. GRB041220: Swift-BAT burst
  84. Deep RAPTOR observations during GRB 041219
  85. GRB041219c: Third Burst in One Day from Swift-BAT
  86. GRB041219b: A Swift-BAT burst
  87. GRB 041219 ,optical observation
  88. GRB 041218: R-band optical observations
  89. Swift-BAT detection of the bright long burst GRB041219
  90. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  91. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  92. GRB041217: The First GRB Located On-Board Swift
  93. GRB041211: RAPTOR observations
  94. GRB041211, BVRcIc field calibration
  95. GRB041211,optical observation
  96. GRB 041211: KAIT observations
  97. Distribution of IBAS Alerts for NON-GRB sources
  98. GRB 041006: GETS Optical Afterglow Observation
  99. Summary of the recent bursts from SGR 1806-20
  100. GRB041015, optical observation in CrAO

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