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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"

28091 results found.

  1. GRB 061218: TORTOREM optical upper limits
  2. GRB 061218, Swift-BAT refined analysis
  3. GRB061217: VLT NIR observations
  4. GRB 061218, SMARTS optical/IR observations
  5. GRB 061218: REM prompt observations
  6. Swift triggers (#251863) on a possible burst
  7. GRB061217: Swift/UVOT refined analysis.
  8. GRB 061217: optical observations at Calar Alto
  9. GRB061217 - Swift/XRT refined analysis
  10. GRB 061217, Swift-BAT refined analysis
  11. GRB 061217: Magellan Observations
  12. GRB 061217: REM prompt observations
  13. GRB 061217: ROTSE-III Optical Limits
  14. GRB061210: Swift/UVOT observations
  15. GRB 061210: Swift XRT analysis - Possible counterparts
  16. GRB 061210: Gemini/GMOS Observations
  17. GRB 061126: Radio Observations
  18. GRB061210: Radio Observations
  19. GRB 061202: Suzaku WAM observation of the prompt emission
  20. GRB 061210, Swift-BAT refined analysis of the SHB
  21. Optical Afterglow observations of GRB 061126
  22. GRB 060926: MASTER: discovery of the optical flare
  23. GRB 061201: UVOT Observations of a Fading Optical Afterglow
  24. GRB 061202: TORTOREM optical upper limits
  25. GRB 061201: VLT optical decay
  26. GRB 061201: SOAR Confirmation of Candidate Afterglow
  27. GRB061202: FRAM early follow-up limit
  28. GRB061202 optical limit by "Pi of the Sky"
  29. GRB061202: optical/NIR observations with REM
  30. GRB061202: Swift/UVOT Upper Limits
  31. GRB 061202, Swift-BAT refined analysis
  32. GRB 061202: Swift detection of a burst
  33. GRB 061201: VLT optical observations
  34. GRB 061201: Initial UVOT Observations
  35. GRB 061201, Swift-BAT refined analysis of the SHB
  36. GRB 061201: Swift detection of a short hard burst
  37. INT+WFC observations of GRB 061126
  38. Swift XRT on-board boresight update
  39. GRB 061126: optical observation
  40. GRB 061126: Tautenburg afterglow observations
  41. GRB061126: Optical afterglow observations from MIRO
  42. GRB061126: Optical afterglow observations from MIRO
  43. GRB 061126 : SDSS Pre-Burst Observations
  44. GRB 061126: Swift-XRT refined analysis
  45. GRB 061126: Swift/UVOT Observations
  46. GRB 061126, Swift-BAT refined analysis
  47. GRB 061126: Early Detection of the IR Afterglow
  48. GRB 061126: Swift/UVOT Afterglow Detection
  49. GRB 061122: Candidate Optical Afterglow
  50. GRB 061121: Ep,i - Eiso correlation
  51. GRB061122: Swift/UVOT Optical Observations
  52. GRB061121: P60 Observations
  53. Radio detection of GRB 061121
  54. GRB061122: Swift-XRT position
  55. INTEGRAL results on GRB 061122
  56. Swift-BAT trigger 239987 is not a GRB
  57. GRB 061121: Swift/UVOT Observations
  58. GRB 061121: Swift-XRT Team Refined Analysis
  59. GRB 061121, Swift-BAT refined analysis
  60. GRB061121, optical observation
  61. GRB 061121: Optical observation at the KANATA 1.5m telescope
  62. GRB 061121: ROTSE-III Confirmation of Optical Counterpart
  63. GRB 061121: Swift detection of a bright burst with an optical counterpart
  64. GRB 060605: NIR Observations
  65. GRB 050915B: optical afterglow
  66. Swift-BAT triggers 238544 and 238546 are not GRBs
  67. Swift/UVOT Upper Limits for GRB061110b
  68. Swift/UVOT Upper Limits for GRB061110a
  69. GRB 061110B, Swift-BAT refined analysis
  70. GRB061110B: Optical observations at Crni Vrh
  71. GRB 061110A: Swift XRT refined analysis
  72. GRB 061110A, Swift-BAT refined analysis
  73. GRB 061110B: TAROT Calern observatory optical observations
  74. GRB 061110B: Swift detection of a burst
  75. GRB 061110: Candidate confirmed
  76. GRB 061110 : Optical afterglow candidate
  77. GRB 061110: ROTSE-III Optical Limits
  78. GRB 061110: Swift detection of a burst
  79. GRB061110A - Optical Non-detection
  80. GRB 061109: optical observation
  81. GRB 061109: TAROT Calern observatory optical observations
  82. GRB 061027: TAROT La Silla observatory optical observations
  83. GRB 061028: Swift/XRT Astrometry Correction
  84. GRB 061102: Swift/UVOT Magnitude Upper Limits
  85. GRB 061102, XRT refined analysis
  86. GRB061102B: Super-LOTIS observations
  87. GRB 061028: Optical R passband observations
  88. GRB 061102B: Swift detection of a possible burst
  89. GRB 061102, Swift-BAT refined analysis
  90. GRB 061102: Swift detection of a burst
  91. GRB 061028: VLA Observation
  92. GRB 061004: Swift/XRT Astrometry Correction
  93. GRB 060801: Swift/XRT Astrometry Correction
  94. GRB 061028: Futher P200 Observations
  95. GRB 061028: P200 Observations
  96. GRB 061028: SARA upper limit
  97. GRB 061028: z band imaging
  98. GRB061028: XRT refined analysis
  99. GRB 061028: Swift/UVOT Observations
  100. GRB 061028, Swift-BAT refined analysis

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