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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"
  1. GRB 100206A: optical observations in Terskol
  2. GRB 100213B: Mondy optical observations
  3. GRB 100219A: optical observations
  4. GRB 100219A: GAO 150cm telescope Optical Observation
  5. GRB 100224A SHB found in ground analysis of BAT data
  6. GRB 100225A: Fermi LAT detection
  7. GRB 100225A: Fermi GBM detection
  8. GRB 100223A: Fermi GBM detection
  9. Swift Triggers 413744 and 413745 are not GRBs
  10. GRB
  11. GRB 100219A: X-shooter refined analysis
  12. GRB 100219A: XRT refined analysis
  13. GRB 100219A - Gemini South Spectroscopy
  14. GRB 100216A: Swift/UVOT Observations
  15. GRB 100219A: VLT/X-shooter redshift
  16. GRB100219A Akeno and Okayama MITSuME Optical Observation
  17. GRB 100219A: GROND observations
  18. GRB 100219A: NOT OA observations
  19. GRB 100219A: Enhanced Swift-XRT position
  20. GRB 100219A: Swift/UVOT Detection of the Optical Afterglow
  21. GRB 100216A: XRT Refined Analysis
  22. GRB 100219A: Swift-BAT refined analysis
  23. GRB 100219A: Pre-explosion imaging and host candidate
  24. GRB 100219A: Swift/UVOT Detection of a Source near the XRT Position
  25. GRB 100218A : Fermi GBM detection
  26. GRB 100219A: Swift detection of a burst
  27. GRB 100216A: Keck imaging
  28. GRB 100216A Short, hard GRB detected in ground analysis of Swift-BAT data
  29. GRB 100213A: Swift-BAT lag analysis indicates probably SHB
  30. GRB 100213B: GRT Optical Observation
  31. GRB 100213A: GRT Optical Observation
  32. GRB 100213A: Swift-BAT refined analysis
  33. GRB 100213B: Enhanced Swift-XRT position
  34. GRB 100213B: Gemini-N Observations
  35. GRB 100213B: Swift/UVOT Upper Limits
  36. GRB 100213A: Swift/UVOT Upper Limits
  37. GRB 100213B: PAIRITEL NIR Upper Limits
  38. GRB 100213A: Enhanced Swift-XRT position
  39. GRB 100213B: Swift-BAT refined analysis
  40. GRB 100213B: Swift XRT refined analysis
  41. GRB 100213A: SARA observations
  42. GRB 100213A: Swift XRT refined analysis
  43. GRB 100213B: NOT optical observations
  44. GRB 100213B: Swift detection of a burst
  45. GRB 100213A: Swift detection of a burst
  46. GRB 100206A: Second epoch Gemini-north observations and afterglow limits
  47. Swift/UVOT observations of GRB100212A - correction of the name of the burst
  48. Swift/UVOT observations of GRB120212A
  49. GRB 100212A: LOAO R-band Detection/V-band Observation
  50. GRB 100212A: Fermi GBM detection
  51. GRB 100212A: Swift XRT refined analysis
  52. GRB 100212A: Swift-BAT refined analysis
  53. GRB 100212A: Enhanced Swift-XRT position
  54. GRB 100212A: candidate optical afterglow
  55. GRB 100212A: Swift detection of a burst
  56. GRB 091127: Detection of a Supernova
  57. GRB 100205A: Keck limits on an underlying host galaxy
  58. GRB 100205A: BOAO/LOAO zYJK observation
  59. GRB 100205B: Fermi GBM detection
  60. GRB 100206A: GROND upper limits
  61. GRB 100206A: Gemini-North observations
  62. GRB 100206A: Swift/UVOT Upper Limits
  63. GRB 100131A: MASTER-Net optical alert observations
  64. GRB 100206A: YNAO-GMG observations
  65. GRB 100206A: MASTER-Net optical alert observations
  66. GRB 100206A: PAIRITEL Photometry of Host Candidate
  67. GRB 100206A - Keck/LRIS Spectroscopy
  68. GRB100206: MITSuME optical upper limits
  69. GRB 100206A: NOT NIR observations
  70. GRB 100206A: WHT candidate afterglow
  71. GRB 100206A, RIMOTS optical upper limits
  72. GRB 100206A: optical observations from Southern Spain
  73. GRB 100205A: GROND upper limits
  74. GRB 100206A: Swift-XRT refined analysis
  75. GRB 100206A: Fermi GBM observation
  76. GRB 100206A: Optical limit
  77. GRB 100206A: Swift-BAT refined analysis
  78. GRB 100206A: Enhanced Swift-XRT position
  79. GRB 100206A: Pre-explosion imaging and host candidate
  80. GRB 100206A: Swift detection of a short hard burst
  81. GRB100205A: CFHT z'-band observation
  82. GRB 100205A: Gemini-N + NIRI photometry
  83. GRB 100130B: Fermi GBM detection
  84. GRB 100113A: Fermi GBM detection
  85. GRB 100205A: Swift-BAT refined analysis
  86. GRB 100205A: Swift UVOT upper limits
  87. GRB 100205A: Swift XRT refined analysis
  88. GRB 100203A: Swift XRT and UVOT refined analyses
  89. GRB 100205A: Enhanced Swift-XRT position
  90. GRB 100205A Gemini-North IR afterglow candidate
  91. GRB 100205A: Gemini-South Observations
  92. GRB 100205A: Super-LOTIS early observations
  93. GRB 100131A: Suzaku WAM observation of the prompt emission
  94. GRB 100205A: NOT optical observations
  95. GRB 100205A: Swift detection of a burst
  96. GRB 100203A Detected in Ground Analysis of BAT Data
  97. Short X-ray Transient detected by MAXI/GSC
  98. GRB 100131A: Fermi GBM detection
  99. GRB 100119A: Suzaku WAM observation of the prompt emission
  100. Konus-Wind observation of GRB 100119A

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