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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"

22917 results found.

  1. GRB 081206C: Fermi GBM detection
  2. GRB 081206B: Fermi GBM detection
  3. GRB 081206: Fermi GBM detection
  4. GRB 081128: afterglow observations
  5. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  6. GRB 081128: optical observation in CrAO
  7. GRB081203A: Optical observations at Ishigaki
  8. GRB 081204: GROND Observations
  9. Radio detection of GRB 081203B with the VLA
  10. GRB081203A: Radio upper limit at 15 GHz
  11. GRB 081204B: Fermi GBM detection
  12. GRB 081204: Swift/UVOT Upper Limits
  13. GRB081203A: MITSuME optical observation
  14. GRB081203A: optical observation
  15. VLA Radio upper limit on GRB 081203A
  16. Konus-Wind observation of GRB 081203A
  17. GRB081203A: Swift-XRT refined analysis
  18. GRB 081203B: optical observations
  19. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  20. Swift/UVOT detection of GRB081203B
  21. GRB 081203B: Swift-XRT candidate afterglow.
  22. GRB 081203A: optical observations
  23. Swift UVOT observations of GRB 081203A
  24. GRB 081203: Enhanced Swift-XRT position
  25. GRB 081130B: MASTER prompt optical observations
  26. GRB081203: optical observation
  27. GRB 081203: Swift detection of a burst with a bright optical counterpart
  28. GRB 081128: optical observation
  29. GRB 081130B: Fermi GBM detection
  30. GRB 081130: Fermi GBM detection
  31. Swift Trigger 335971: Swift/UVOT Observations
  32. GRB 081126: afterglow photometry
  33. VLA Radio upper limit on GRB 081126
  34. GRB 081129: Fermi GBM detection
  35. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  36. GRB 081128A: optical observations
  37. Swift Trigger 335971 is probably not a real source
  38. Trigger 335971: Swift possible detection of a burst
  39. GRB081128: Swift/UVOT Upper Limits
  40. GRB 081122B: Fermi GBM Detection
  41. GRB 081128: Swift-XRT refined analysis
  42. GRB 081128: Liverpool Telescope afterglow confirmation
  43. GRB081128: optical observations
  44. GRB 081128: Enhanced Swift-XRT position
  45. GRB 081128: Optical observation of xinglong TNT
  46. GRB 081128: Swift detection of a burst
  47. GRB 081126: GRT Optical Observation
  48. GRB 081127: Swift/UVOT Upper Limits
  49. GRB 081127: Enhanced Swift-XRT position
  50. GRB 081126: Confirmation of the Optical Afterglow
  51. Konus-Wind observation of GRB 081126
  52. GRB 081126: Swift-XRT refined analysis
  53. GRB 081127: Swift detection of a burst
  54. GRB 081126: Swift/UVOT Observations
  55. GRB 081126: optical observations
  56. GRB 081126: Enhanced Swift-XRT position
  57. GRB 081126: TAROT Calern observatory optical observations
  58. GRB 081126: Swift detection of a burst
  59. GRB 081125: Fermi GBM detection
  60. GRB 081124: Fermi GBM detection
  61. GRB 081120: Fermi GBM detection
  62. GRB 081118: Fermi GBM detection.
  63. GRB 081122: Fermi GBM detection
  64. GRB 081121, SMARTS optical/IR afterglow observations
  65. GRB081121: Refined Swift/UVOT observations
  66. GRB 081121: Swift-XRT refined analysis
  67. GRB 081121: Enhanced Swift-XRT position
  68. GRB 081121: GROND observations
  69. GRB081121: Swift/UVOT observations
  70. GRB 081121: Swift detection of a burst
  71. GRB081118 : optical upper limit
  72. GRB 081119: Fermi GBM detection
  73. VLA Radio upper limit on GRB 081118
  74. GRB 081118: Swift-XRT refined analysis
  75. GRB 081118: GROND detection of afterglow
  76. GRB 081118: optical afterglow candidate
  77. GRB 081118: Swift UVOT Upper Limits
  78. GRB 081118: Enhanced Swift-XRT position
  79. GRB 081118: Swift detection of a burst
  80. GRB 081109A: confirmation of possible detection host galaxy
  81. Further Swift-XRT observations of the probable GRB 081105.
  82. GRB 081113: Fermi GBM detection
  83. GRB 081102: RTT150 Optical observations
  84. GRB 081110: Fermi GBM detection
  85. GRB 081109: TAROT La Silla observatory optical observations
  86. GRB 081102: MASTER refind and final results
  87. GRB 081109: GROND redshift limit and host extinction
  88. GRB 081025: Swift-XRT further analysis
  89. GRB 081024B: Swift-XRT late-time observations
  90. GRB 081109: GROND Detection of the Optical/NIR Afterglow Candidate
  91. GRB 081109A: Possible Swift-UVOT detection
  92. GRB 081109A: Swift-XRT refined analysis
  93. GRB 081109: Swift/UVOT upper limits
  94. Swift-BAT Trigger 334129: possible burst
  95. GRB 081109: REM NIR afterglow detection
  96. GRB 081109: Swift detection of a burst
  97. GRB 081024C: Fermi Gamma-ray Burst Monitor detection
  98. GRB 081102B: Fermi GBM detection
  99. GRB 081105B: Fermi GBM detection
  100. GRB 081107: Fermi GBM detection

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