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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"

23417 results found.

  1. GRB 100316A: optical observations in CrAO
  2. GRB 100316D: Swift/UVOT Observations
  3. GRB 100316D: Swift XRT enhanced position and further refined analysis
  4. GRB 100316C: GROND Detection of a Optical/NIR Afterglow Candidate
  5. GRB 100316D: GROND Detection of the Optical/NIR Afterglow Candidate
  6. GRB 100316D: Gemini/GMOS and VLT/X-shooter observations
  7. GRB 100316D: VLT/X-shooter observations
  8. GRB100316C: Swift/UVOT Upper Limits
  9. GRB 100316C: Swift-BAT refined analysis
  10. GRB 100316B: Swift/UVOT observations
  11. GRB 100316C: Enhanced Swift-XRT position
  12. GRB 100316A: TAROT Calern observatory optical observations
  13. GRB 100316A: Swift-XRT refined analysis
  14. GRB 100316B: Enhanced Swift-XRT position
  15. GRB100316A: Swift/UVOT Upper Limits
  16. Trigger 416140 is almost certainly not a GRB
  17. GRB 100316C: BOOTES-3 observations
  18. GRB 100316D: Swift detection of a burst
  19. GRB 100316B: GROND Detection of the Optical/NIR Afterglow Candidate
  20. GRB 100316C: Swift detection of a burst
  21. GRB 100316A: Enhanced Swift-XRT position
  22. GRB 100316B: Swift detection of a burst with optical counterpart
  23. GRB 100316A: Swift/UVOT Observations
  24. GRB 100316A: Swift detection of a burst
  25. GRB100305A: Optical upper limits at IAO
  26. GRB 100305A: Super-LOTIS early observations
  27. GRB100302A : LOAO observations and Lulin afterglow analysis
  28. GRB 100305A: Gemini z'-band observation
  29. GRB 100305A: Swift/UVOT Upper Limits
  30. GRB 100305A Optical Observations
  31. GRB 100305A: Enhanced Swift-XRT position
  32. GRB 100305A: Gemini-N OT candidate
  33. GRB 100305A: PAIRITEL NIR Upper Limits
  34. GRB 100305A: P60 Observations
  35. GRB 100305A: Swift detection of a burst
  36. GRB 100302A: Ondrejov 65cm limit
  37. GRB 100302A: Swift/UVOT Upper Limits
  38. GRB 100302A: Swift-XRT refined analysis
  39. GRB 100302A: Gemini-N OT confirmation
  40. GRB 100302A: Optical observations at Crni Vrh
  41. GRB 100302A: MASTER-Net optical alert observations
  42. GRB 1000302A : A possible afterglow candidate
  43. GRB 100302A: Enhanced Swift-XRT position
  44. GRB 100302A: Skynet/DAO Observations
  45. GRB 100302A: Swift detection of a burst
  46. GRB 100224B: Fermi GBM detection
  47. GRB 100206A: optical observations in CrAO
  48. GRB 100206A: optical observations in Terskol
  49. GRB 100213B: Mondy optical observations
  50. GRB 100219A: optical observations
  51. GRB 100219A: GAO 150cm telescope Optical Observation
  52. GRB 100224A SHB found in ground analysis of BAT data
  53. GRB 100225A: Fermi LAT detection
  54. GRB 100225A: Fermi GBM detection
  55. GRB 100223A: Fermi GBM detection
  56. GRB
  57. GRB 100216A: Swift/UVOT Observations
  58. GRB100219A Akeno and Okayama MITSuME Optical Observation
  59. GRB 100219A: GROND observations
  60. GRB 100219A: NOT OA observations
  61. GRB 100219A: Enhanced Swift-XRT position
  62. GRB 100219A: Swift/UVOT Detection of the Optical Afterglow
  63. GRB 100219A: Pre-explosion imaging and host candidate
  64. GRB 100219A: Swift/UVOT Detection of a Source near the XRT Position
  65. GRB 100218A : Fermi GBM detection
  66. GRB 100219A: Swift detection of a burst
  67. GRB 100216A: Keck imaging
  68. GRB 100216A Short, hard GRB detected in ground analysis of Swift-BAT data
  69. GRB 100213B: GRT Optical Observation
  70. GRB 100213A: GRT Optical Observation
  71. GRB 100213B: Enhanced Swift-XRT position
  72. GRB 100213B: Gemini-N Observations
  73. GRB 100213B: Swift/UVOT Upper Limits
  74. GRB 100213A: Swift/UVOT Upper Limits
  75. GRB 100213B: PAIRITEL NIR Upper Limits
  76. GRB 100213A: Enhanced Swift-XRT position
  77. GRB 100213A: SARA observations
  78. GRB 100213B: NOT optical observations
  79. GRB 100213B: Swift detection of a burst
  80. GRB 100213A: Swift detection of a burst
  81. GRB 100206A: Second epoch Gemini-north observations and afterglow limits
  82. Swift/UVOT observations of GRB120212A
  83. GRB 100212A: Enhanced Swift-XRT position
  84. GRB 100212A: candidate optical afterglow
  85. GRB 100212A: Swift detection of a burst
  86. GRB 091127: Detection of a Supernova
  87. GRB 100205A: Keck limits on an underlying host galaxy
  88. GRB 100205A: BOAO/LOAO zYJK observation
  89. GRB 100205B: Fermi GBM detection
  90. GRB 100206A: GROND upper limits
  91. GRB 100206A: Gemini-North observations
  92. GRB 100206A: Swift/UVOT Upper Limits
  93. GRB 100131A: MASTER-Net optical alert observations
  94. GRB 100206A: YNAO-GMG observations
  95. GRB 100206A: MASTER-Net optical alert observations
  96. GRB 100206A: PAIRITEL Photometry of Host Candidate
  97. GRB100206: MITSuME optical upper limits
  98. GRB 100206A: NOT NIR observations
  99. GRB 100206A, RIMOTS optical upper limits
  100. GRB 100205A: GROND upper limits

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