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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"

22856 results found.

  1. GRB081203A: BTA observation
  2. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  3. GRB081222: REM candidate afterglow
  4. GRB 081222: Swift detection of a burst with a bright optical afterglow
  5. GRB 081221: Enhanced Swift-XRT position
  6. GRB 081221: further NOT observations
  7. GRB 081221: NOT observations
  8. GRB 081221: Swift detection of a burst
  9. GRB 081217: Fermi GBM detection
  10. GRB 081211B: Further Swift-XRT analysis
  11. GRB 081215B: Fermi GBM detection
  12. GRB 081216 : Fermi GBM observation
  13. GRB 081215A: Fermi GBM detection
  14. IPN localization of short hard GRB 081216
  15. GRB 081118: Zadko observations
  16. Fermi Trig Num 251059717 = SGR 0044+42: MASTER prompt optical observations
  17. GRB 0811215A: MASTER prompt optical observations
  18. GRB 081215A: Andromeda inside Fermi error box: MASTER observations
  19. GRB 0811215A: Andromeda inside Fermi error box: MASTER observations
  20. Possible GRB 081211B: Swift/UVOT Upper Limits
  21. GRB 081213: Fermi GBM detection
  22. GRB 081210: optical observations
  23. Possible GRB 081211B - Swift-XRT analysis
  24. GRB 081207: Fermi GBM detection
  25. GRB 081209: Fermi GBM detection
  26. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  27. GRB 081210: Xinglong TNT R band Upper Limits
  28. GRB 081210, SMARTS optical/IR observations
  29. GRB 081211: Swift-BAT refined analysis
  30. GRB 081211: Swift/UVOT detection of an optical afterglow
  31. GRB 081211: Enhanced Swift-XRT position
  32. GRB 081210: Swift/UVOT refined analysis
  33. GRB 081211: Swift detection of a burst
  34. GRB081203B: optical observations
  35. GRB 081210: Enhanced Swift-XRT position
  36. GRB 081210: Swift detection of a burst with optical afterglow
  37. Konus-Wind observation of GRB 081209
  38. IPN triangulation of short hard GRB 081209
  39. GRB 081203A: optical observations
  40. GRB 081206C: Fermi GBM detection
  41. GRB 081206B: Fermi GBM detection
  42. GRB 081206: Fermi GBM detection
  43. GRB 081128: afterglow observations
  44. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  45. GRB 081128: optical observation in CrAO
  46. GRB081203A: Optical observations at Ishigaki
  47. GRB 081204: GROND Observations
  48. Radio detection of GRB 081203B with the VLA
  49. GRB081203A: Radio upper limit at 15 GHz
  50. GRB 081204B: Fermi GBM detection
  51. GRB 081204: Swift/UVOT Upper Limits
  52. GRB081203A: MITSuME optical observation
  53. GRB081203A: optical observation
  54. VLA Radio upper limit on GRB 081203A
  55. Konus-Wind observation of GRB 081203A
  56. GRB081203A: Swift-XRT refined analysis
  57. GRB 081203B: optical observations
  58. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  59. Swift/UVOT detection of GRB081203B
  60. GRB 081203B: Swift-XRT candidate afterglow.
  61. GRB 081203A: optical observations
  62. Swift UVOT observations of GRB 081203A
  63. GRB 081203: Enhanced Swift-XRT position
  64. GRB 081130B: MASTER prompt optical observations
  65. GRB081203: optical observation
  66. GRB 081203: Swift detection of a burst with a bright optical counterpart
  67. GRB 081128: optical observation
  68. GRB 081130B: Fermi GBM detection
  69. GRB 081130: Fermi GBM detection
  70. Swift Trigger 335971: Swift/UVOT Observations
  71. GRB 081126: afterglow photometry
  72. VLA Radio upper limit on GRB 081126
  73. GRB 081129: Fermi GBM detection
  74. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  75. GRB 081128A: optical observations
  76. Swift Trigger 335971 is probably not a real source
  77. Trigger 335971: Swift possible detection of a burst
  78. GRB081128: Swift/UVOT Upper Limits
  79. GRB 081122B: Fermi GBM Detection
  80. GRB 081128: Swift-XRT refined analysis
  81. GRB 081128: Liverpool Telescope afterglow confirmation
  82. GRB081128: optical observations
  83. GRB 081128: Enhanced Swift-XRT position
  84. GRB 081128: Optical observation of xinglong TNT
  85. GRB 081128: Swift detection of a burst
  86. GRB 081126: GRT Optical Observation
  87. GRB 081127: Swift/UVOT Upper Limits
  88. GRB 081127: Enhanced Swift-XRT position
  89. GRB 081126: Confirmation of the Optical Afterglow
  90. Konus-Wind observation of GRB 081126
  91. GRB 081126: Swift-XRT refined analysis
  92. GRB 081127: Swift detection of a burst
  93. GRB 081126: Swift/UVOT Observations
  94. GRB 081126: optical observations
  95. GRB 081126: Enhanced Swift-XRT position
  96. GRB 081126: TAROT Calern observatory optical observations
  97. GRB 081126: Swift detection of a burst
  98. GRB 081125: Fermi GBM detection
  99. GRB 081124: Fermi GBM detection
  100. GRB 081120: Fermi GBM detection

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