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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"

28048 results found.

  1. GRB 100212A: Fermi GBM detection
  2. GRB 100212A: Swift XRT refined analysis
  3. GRB 100212A: Swift-BAT refined analysis
  4. GRB 100212A: Enhanced Swift-XRT position
  5. GRB 100212A: candidate optical afterglow
  6. GRB 100212A: Swift detection of a burst
  7. GRB 091127: Detection of a Supernova
  8. GRB 100205A: Keck limits on an underlying host galaxy
  9. GRB 100205A: BOAO/LOAO zYJK observation
  10. GRB 100205B: Fermi GBM detection
  11. GRB 100206A: GROND upper limits
  12. GRB 100206A: Gemini-North observations
  13. GRB 100206A: Swift/UVOT Upper Limits
  14. GRB 100131A: MASTER-Net optical alert observations
  15. GRB 100206A: YNAO-GMG observations
  16. GRB 100206A: MASTER-Net optical alert observations
  17. GRB 100206A: PAIRITEL Photometry of Host Candidate
  18. GRB100206: MITSuME optical upper limits
  19. GRB 100206A: NOT NIR observations
  20. GRB 100206A, RIMOTS optical upper limits
  21. GRB 100205A: GROND upper limits
  22. GRB 100206A: Swift-XRT refined analysis
  23. GRB 100206A: Optical limit
  24. GRB 100206A: Swift-BAT refined analysis
  25. GRB 100206A: Enhanced Swift-XRT position
  26. GRB 100206A: Pre-explosion imaging and host candidate
  27. GRB 100206A: Swift detection of a short hard burst
  28. GRB100205A: CFHT z'-band observation
  29. GRB 100205A: Gemini-N + NIRI photometry
  30. GRB 100130B: Fermi GBM detection
  31. GRB 100113A: Fermi GBM detection
  32. GRB 100205A: Swift-BAT refined analysis
  33. GRB 100205A: Swift UVOT upper limits
  34. GRB 100205A: Swift XRT refined analysis
  35. GRB 100203A: Swift XRT and UVOT refined analyses
  36. GRB 100205A: Enhanced Swift-XRT position
  37. GRB 100205A Gemini-North IR afterglow candidate
  38. GRB 100205A: Gemini-South Observations
  39. GRB 100205A: Super-LOTIS early observations
  40. GRB 100131A: Suzaku WAM observation of the prompt emission
  41. GRB 100205A: NOT optical observations
  42. GRB 100205A: Swift detection of a burst
  43. Short X-ray Transient detected by MAXI/GSC
  44. GRB 100131A: Fermi GBM detection
  45. GRB 100119A: Suzaku WAM observation of the prompt emission
  46. GRB 100122A: Fermi GBM detection
  47. GRB 100122A: MASTER-Net optical observations
  48. GRB 100116A: Suzaku WAM observation of the prompt emission
  49. GRB 100115A: Swift-XRT refined analysis
  50. GRB 100119A: Swift-BAT refined analysis
  51. Swift/UVOT refined analysis of GRB100117A
  52. GRB 100117A: Swift-XRT refined analysis
  53. GRB 100117A: Gemini-North upper limit
  54. GRB 100117A: Magellan IMACS imaging
  55. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  56. GRB 100117A: Swift-BAT refined analysis
  57. GRB100117A: Possible afterglow from NOT observation
  58. GRB 100117A: Swift detection of a short hard burst
  59. GRB 100115A: Gemini-N photometry
  60. GRB 100115A: Enhanced Swift-XRT position
  61. GRB 100116A: Fermi LAT detection
  62. GRB 100115A: SARA Astrometry
  63. GRB 100116A: Fermi GBM detection
  64. GRB 100115A: SARA Afterglow Candidate
  65. GRB 100115A: Swift/UVOT Upper Limits
  66. GRB 100115A: Swift-XRT candidate afterglow
  67. GRB 100111A: PAIRITEL NIR Upper Limits
  68. GRB 100111A: Swift UVOT Refined Analysis
  69. GRB 100111A: Swift-BAT refined analysis
  70. GRB 100111A: Enhanced Swift-XRT position
  71. GRB100111A: Swift-XRT refined analysis
  72. GRB 100111A: Fermi GBM observation
  73. GRB 100111A: NOT optical observations
  74. GRB 100111A: Swift detection of a burst with an optical afterglow
  75. Swift/BAT Detects an Outburst from XTE J1901+014
  76. GRB 100103A: GROND Upper Limits
  77. GRB 100103A: Swift-XRT team refined analysis
  78. GRB 100103A - UVOT-enhanced XRT position
  79. GRB 100103A: Swift/XRT position
  80. GRB 100103A: a long GRB detected with INTEGRAL
  81. Swift Trigger 381591 is probably not a burst
  82. GRB 091231: GROND NIR observations
  83. Swift Trigger 381591: Uncatalogued UVOT Source
  84. GRB 091230: Swift/UVOT Observations
  85. Trigger 381591: Swift detection of a possible burst
  86. GRB 091230: Swift-XRT observation
  87. GRB 091230: GROND optical/NIR afterglow candidate
  88. Swift Trigger 381434 is not a GRB
  89. Trigger 381434: Swift detection of a possible burst
  90. GRB 091221: Skynet/PROMPT Detections
  91. GRB 091221: Fermi GBM Observation
  92. GRB 091117: Swift-XRT late time observations
  93. GRB 091221 Swift-BAT refined analysis
  94. GRB 091221: Swift/UVOT refined analysis
  95. GRB 091221: Swift-XRT refined analysis
  96. GRB 091221: Enhanced Swift-XRT position
  97. GRB 091221: UVOT Confirmation of an Optical Afterglow
  98. GRB 091221: ROTSE-III Detection of Optical Counterpart
  99. GRB 091221: Swift detection of a burst
  100. Swift trigger 379449 (possible GRB) is not a burst

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