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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. GRB081215A: Fermi-LAT observations
  2. GRB 081211B: Further Swift-XRT analysis
  3. GRB 081215B: Fermi GBM detection
  4. GRB 081216: Suzaku WAM observation of the prompt emission
  5. GRB 081216 : Fermi GBM observation
  6. GRB 081215A: Fermi GBM detection (correction to event fluence)
  7. GRB 081215A: Fermi GBM detection
  8. IPN localization of short hard GRB 081216
  9. GRB 081211B - possibly a short burst with extended emission
  10. GRB 081118: Zadko observations
  11. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  12. GRB 081215A: Gamma Repeater?
  13. GRB 0811215A: MASTER prompt optical observations
  14. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  15. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  16. Possible GRB 081211B: Swift/UVOT Upper Limits
  17. GRB 081213: Fermi GBM detection
  18. GRB 081210: optical observations
  19. Possible GRB 081211B - Swift-XRT analysis
  20. GRB 081207: Fermi GBM detection
  21. GRB 081209: Fermi GBM detection
  22. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  23. GRB 081007: Detection of a Supernova
  24. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  25. GRB 081210: Xinglong TNT R band Upper Limits
  26. GRB 081210, SMARTS optical/IR observations
  27. GRB 081211: Swift-BAT refined analysis
  28. GRB 081211: Swift XRT refined analysis
  29. GRB 081211: Swift/UVOT detection of an optical afterglow
  30. GRB 081211: Enhanced Swift-XRT position
  31. GRB 081210: Swift/UVOT refined analysis
  32. GRB 081211: Swift detection of a burst
  33. GRB 081210: Swift-XRT refined analysis
  34. GRB081203B: optical observations
  35. GRB 081210: Enhanced Swift-XRT position
  36. GRB 081210: Swift-BAT refined analysis
  37. GRB 081210: Swift detection of a burst with optical afterglow
  38. Konus-Wind observation of GRB 081209
  39. IPN triangulation of short hard GRB 081209
  40. GRB 081203A: optical observations
  41. GRB 081206C: Fermi GBM detection
  42. Radio observation of GRB 081121 with ATCA
  43. Radio observation of GRB 081118 with ATCA
  44. GRB 081206B: Fermi GBM detection
  45. GRB 081206: Fermi GBM detection
  46. GRB 081128: afterglow observations
  47. GRB 081203B: Suzaku WAM observation of the prompt emission
  48. GRB 081203B: Additional Gemini imaging
  49. Radio observation of GRB 081109 with ATCA
  50. Radio observation of GRB 081104 with ATCA
  51. Radio observation of GRB 081029 with ATCA
  52. Radio observation of GRB 081008 with ATCA
  53. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  54. GRB 081203B: Gemini observations
  55. GRB 081128: optical observation in CrAO
  56. GRB081203A: Optical observations at Ishigaki
  57. GRB 081128: Optical afterglow observations
  58. GRB 081204: GROND Observations
  59. GRB081203B: optical observations
  60. Radio detection of GRB 081203B with the VLA
  61. GRB 081204: Magellan observations
  62. GRB081203A: Radio upper limit at 15 GHz
  63. GRB 081204B: Fermi GBM detection
  64. GRB 081204: Swift/UVOT Upper Limits
  65. GRB 081204: Swift XRT afterglow confirmation
  66. GRB081203A: MITSuME optical observation
  67. GRB 081203A: Optical observations of Xinglong TNT telescope
  68. GRB 081203A: Skynet/GORT Detections
  69. GRB 081204: Swift XRT afterglow candidate
  70. GRB081203A: optical observation
  71. GRB 081204 : a long GRB localized by INTEGRAL
  72. VLA Radio upper limit on GRB 081203A
  73. Swift-XRT observations of GRB 081203B
  74. Konus-Wind observation of GRB 081203A
  75. Konus-Wind observation of GRB 081203B
  76. GRB081203A: Swift-XRT refined analysis
  77. GRB 081203B: optical observations
  78. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  79. Swift/UVOT detection of GRB081203B
  80. GRB 081203B: Swift-XRT candidate afterglow.
  81. GRB 081203A: optical observations
  82. Swift UVOT observations of GRB 081203A
  83. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  84. GRB081203A: Swift/UVOT grism redshift
  85. GRB 081203A: Burst detection from Swift-BAT slew data
  86. GRB 081203A: Swift-BAT refined analysis
  87. GRB 081203: Enhanced Swift-XRT position
  88. GRB 081130B: MASTER prompt optical observations
  89. GRB081203: optical observation
  90. GRB 081203: Swift detection of a burst with a bright optical counterpart
  91. GRB 081128: optical observation
  92. GRB 081130B: Fermi GBM detection
  93. GRB 081130: Fermi GBM detection
  94. Swift Trigger 335971: Swift/UVOT Observations
  95. GRB 081126: afterglow photometry
  96. GRB 081126: Fermi GBM detection
  97. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  98. VLA Radio upper limit on GRB 081126
  99. GRB 081129: Fermi GBM detection
  100. GRB 081130: MASTER VWF prompt optical observations Fermi GRB

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