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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"

18732 results found.

  1. Swift XRT Observation of GRB 060204C
  2. GRB 060204B: Swift-BAT refined analysis
  3. GRB060204B: Swift XRT Team Refined Analysis
  4. GRB 060204C: OSN limits
  5. GRB 060204C: Liverpool Telescopes optical limit
  6. GRB 060204C: ROTSE-III Optical Limits
  7. GRB 060204C: Swift-BAT detection of a burst
  8. GRB 060124: Radio Observations
  9. GRB060204B: Faulkes OT candidate
  10. GRB060204B, optical observation
  11. GRB060204B - SDSS pre-burst observations
  12. GRB 060203: Swift-BAT refined analysis
  13. GRB 060204B: Swift detection of a burst
  14. GRB 060203: RTT150 optical observations
  15. GRB060203: Swift XRT Team Refined Analysis
  16. GRB060203 - Swift UVOT observation
  17. Swift-BAT trigger is GRB 060203
  18. GRB060203: Observations with SARA
  19. GRB 060203: P60 Confirmation of Optical Afterglow
  20. Possible GRB 060203: candidate optical counterpart
  21. Swift BAT Trigger 180151: Swift XRT source detection
  22. Possible GRB 060203: optical observations at Asiago
  23. Swift-BAT trigger 180151 is unknown origin at this time
  24. GRB 060202: Refined analysis of the Swift-BAT burst
  25. GRB060202, optical observation
  26. GRB 060202: Swift/UVOT upper limits
  27. GRB 060202: Swift XRT Team Refined Analysis
  28. GRB060202: Faulkes North observation
  29. GRB 060202: Swift detection of a burst
  30. GRB 060130: Swift/XRT observation
  31. GRB 060123: VLA Radio Observations
  32. Possible GRB 051221B: MDM Correction
  33. GRB 060123: Swift refined analysis of an unusual GRB
  34. GRB060124, BVRcIc field calibration
  35. GRB060105: refined analysis of the Suzaku observation
  36. GRB 060124: HETE detection and spectrum of the main peak
  37. Konus-Wind observation of GRB 060124
  38. GRB060124: detailed XRT analysis
  39. GRB 060124 Optical Observations
  40. GRB 060124: R band Observations
  41. GRB 060124: Extremely long burst, Swift-BAT refined analysis
  42. GRB 060123: Swift detection of a very long, faint burst
  43. GRB 060124: TAROT optical limits
  44. GRB 060124: Swift/UVOT Observation
  45. GRB 060124: Confirmation of the Afterglow
  46. GRB 060124: XRT position
  47. GRB 060124: Optical Observations at Tautenburg
  48. GRB 060117: Suzaku WAM observation of the prompt emission
  49. GRB060124:MASTER optical observation
  50. GRB 060111B: Suzaku WAM observation of the prompt emission
  51. GRB 060124: Swift-BAT detection of a burst
  52. GRB 060116: Radio Detection
  53. GRB 060116: MARGE optical observations
  54. GRB 060121: Swift/UVOT upper limits
  55. GRB 060121: Liverpool Telescopes optical limits
  56. GRB 060121: Swift XRT refined analysis
  57. GRB 060121: Swift XRT refined position
  58. GRB 060117: pseudo-z from spectral parameters of the prompt emission
  59. Konus-Wind observation of GRB 060117
  60. GRB 060117: Refined analysis of the Swift-BAT burst
  61. GRB 060117: FRAM optical afterglow candidate
  62. GRB 060117: Swift-BAT detection of a bright burst
  63. GRB 060116: Refined analysis of the Swift-BAT burst
  64. GRB 060116: Swift/UVOT upper limits
  65. GRB060115: REM observations
  66. GRB 060110: XRT position and analysis
  67. GRB 060116: ROTSE-III Optical Limits
  68. GRB060116: XRT position
  69. GRB060116: Faulkes North observation
  70. GRB 060116: Swift-BAT detection of a burst
  71. GRB 060115: Refined analysis of the Swift-BAT burst
  72. GRB 060115: Swift/UVOT upper limits
  73. GRB 060115: Swift XRT refined analysis
  74. GRB 060114: Swift/UVOT Observations
  75. GRB 060115: MITSuME optical afterglow candidate
  76. GRB 060115: Swift detection of a burst
  77. GRB 060114: Swift XRT upper limit
  78. GRB 060110: KAIT observations
  79. GRB 060111B: Swift XRT refined analysis
  80. GRB 060111A: refined UVOT anaysis
  81. GRB 060111B: TAROT optical observation
  82. GRB060111A: RTT150 optical observations
  83. GRB060111B: RTT150, possible host galaxy
  84. GRB 060111B: Refined analysis of the Swift-BAT burst
  85. GRB 060110: MARGE observations
  86. GRB 060111B: ROTSE-III Detection of Optical Counterpart Flare
  87. GRB 060111B: Swift detection of a burst
  88. GRB 060111: Swift-BAT Refined Analysis
  89. GRB 060111: TAROT optical observation
  90. GRB 060111: possible UVOT counterpart
  91. GRB060111 : XRT refined analysis
  92. GRB 060111: ROTSE-III Optical Limits
  93. GRB 060111: Swift detection of a burst
  94. GRB 060110: Swift-BAT refined analysis
  95. GRB 060109: Swift-BAT refined analysis
  96. GRB 060110a: RAPTOR detection of early optical emission.
  97. Correction to GRB 060109 XRT analysis
  98. GRB 060110: Swift-BAT detection of a burst
  99. GRB 060109: Refined Swift-XRT analysis
  100. GRB 060109: Swift/UVOT upper limits

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