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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"

28038 results found.

  1. GRB 100206A: GROND upper limits
  2. GRB 100206A: Gemini-North observations
  3. GRB 100206A: Swift/UVOT Upper Limits
  4. GRB 100131A: MASTER-Net optical alert observations
  5. GRB 100206A: YNAO-GMG observations
  6. GRB 100206A: MASTER-Net optical alert observations
  7. GRB 100206A: PAIRITEL Photometry of Host Candidate
  8. GRB100206: MITSuME optical upper limits
  9. GRB 100206A: NOT NIR observations
  10. GRB 100206A, RIMOTS optical upper limits
  11. GRB 100205A: GROND upper limits
  12. GRB 100206A: Swift-XRT refined analysis
  13. GRB 100206A: Optical limit
  14. GRB 100206A: Swift-BAT refined analysis
  15. GRB 100206A: Enhanced Swift-XRT position
  16. GRB 100206A: Pre-explosion imaging and host candidate
  17. GRB 100206A: Swift detection of a short hard burst
  18. GRB100205A: CFHT z'-band observation
  19. GRB 100205A: Gemini-N + NIRI photometry
  20. GRB 100130B: Fermi GBM detection
  21. GRB 100113A: Fermi GBM detection
  22. GRB 100205A: Swift-BAT refined analysis
  23. GRB 100205A: Swift UVOT upper limits
  24. GRB 100205A: Swift XRT refined analysis
  25. GRB 100203A: Swift XRT and UVOT refined analyses
  26. GRB 100205A: Enhanced Swift-XRT position
  27. GRB 100205A Gemini-North IR afterglow candidate
  28. GRB 100205A: Gemini-South Observations
  29. GRB 100205A: Super-LOTIS early observations
  30. GRB 100131A: Suzaku WAM observation of the prompt emission
  31. GRB 100205A: NOT optical observations
  32. GRB 100205A: Swift detection of a burst
  33. Short X-ray Transient detected by MAXI/GSC
  34. GRB 100131A: Fermi GBM detection
  35. GRB 100119A: Suzaku WAM observation of the prompt emission
  36. GRB 100122A: Fermi GBM detection
  37. GRB 100122A: MASTER-Net optical observations
  38. GRB 100116A: Suzaku WAM observation of the prompt emission
  39. GRB 100115A: Swift-XRT refined analysis
  40. GRB 100119A: Swift-BAT refined analysis
  41. Swift/UVOT refined analysis of GRB100117A
  42. GRB 100117A: Swift-XRT refined analysis
  43. GRB 100117A: Gemini-North upper limit
  44. GRB 100117A: Magellan IMACS imaging
  45. GRB 100117A: Gemini South Imaging and CFHT Pre-Explosion Images
  46. GRB 100117A: Swift-BAT refined analysis
  47. GRB100117A: Possible afterglow from NOT observation
  48. GRB 100117A: Swift detection of a short hard burst
  49. GRB 100115A: Gemini-N photometry
  50. GRB 100115A: Enhanced Swift-XRT position
  51. GRB 100116A: Fermi LAT detection
  52. GRB 100115A: SARA Astrometry
  53. GRB 100116A: Fermi GBM detection
  54. GRB 100115A: SARA Afterglow Candidate
  55. GRB 100115A: Swift/UVOT Upper Limits
  56. GRB 100115A: Swift-XRT candidate afterglow
  57. GRB 100111A: PAIRITEL NIR Upper Limits
  58. GRB 100111A: Swift UVOT Refined Analysis
  59. GRB 100111A: Swift-BAT refined analysis
  60. GRB 100111A: Enhanced Swift-XRT position
  61. GRB100111A: Swift-XRT refined analysis
  62. GRB 100111A: Fermi GBM observation
  63. GRB 100111A: NOT optical observations
  64. GRB 100111A: Swift detection of a burst with an optical afterglow
  65. Swift/BAT Detects an Outburst from XTE J1901+014
  66. GRB 100103A: GROND Upper Limits
  67. GRB 100103A: Swift-XRT team refined analysis
  68. GRB 100103A - UVOT-enhanced XRT position
  69. GRB 100103A: Swift/XRT position
  70. GRB 100103A: a long GRB detected with INTEGRAL
  71. Swift Trigger 381591 is probably not a burst
  72. GRB 091231: GROND NIR observations
  73. Swift Trigger 381591: Uncatalogued UVOT Source
  74. GRB 091230: Swift/UVOT Observations
  75. Trigger 381591: Swift detection of a possible burst
  76. GRB 091230: Swift-XRT observation
  77. GRB 091230: GROND optical/NIR afterglow candidate
  78. Swift Trigger 381434 is not a GRB
  79. Trigger 381434: Swift detection of a possible burst
  80. GRB 091221: Skynet/PROMPT Detections
  81. GRB 091221: Fermi GBM Observation
  82. GRB 091117: Swift-XRT late time observations
  83. GRB 091221 Swift-BAT refined analysis
  84. GRB 091221: Swift/UVOT refined analysis
  85. GRB 091221: Swift-XRT refined analysis
  86. GRB 091221: Enhanced Swift-XRT position
  87. GRB 091221: UVOT Confirmation of an Optical Afterglow
  88. GRB 091221: ROTSE-III Detection of Optical Counterpart
  89. GRB 091221: Swift detection of a burst
  90. Swift trigger 379449 (possible GRB) is not a burst
  91. GRB 091215: Faulkes Telescope North observations
  92. Trigger 379449: Swift detection of a possible burst
  93. GRB 091208A: Suzaku WAM observation of the prompt emission
  94. GRB 091208A: GAO 150cm telescope Optical Observation
  95. GRB091208A: Swift/UVOT refined analysis
  96. GRB 091208B: optical observations
  97. GRB 091208B: GROND observations
  98. GRB 091208A: Swift-XRT observations
  99. GRB091208B: NOT optical observations
  100. GRB 091208B: Swift-XRT refined analysis

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