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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"

28081 results found.

  1. GRB 081210: Swift-XRT refined analysis
  2. GRB081203B: optical observations
  3. GRB 081210: Enhanced Swift-XRT position
  4. GRB 081210: Swift-BAT refined analysis
  5. GRB 081210: Swift detection of a burst with optical afterglow
  6. IPN triangulation of short hard GRB 081209
  7. GRB 081203A: optical observations
  8. GRB 081206C: Fermi GBM detection
  9. Radio observation of GRB 081121 with ATCA
  10. Radio observation of GRB 081118 with ATCA
  11. GRB 081206B: Fermi GBM detection
  12. GRB 081206: Fermi GBM detection
  13. GRB 081128: afterglow observations
  14. GRB 081203B: Suzaku WAM observation of the prompt emission
  15. Radio observation of GRB 081109 with ATCA
  16. Radio observation of GRB 081104 with ATCA
  17. Radio observation of GRB 081029 with ATCA
  18. Radio observation of GRB 081008 with ATCA
  19. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  20. GRB081203A: Optical observations at Ishigaki
  21. GRB 081204: GROND Observations
  22. Radio detection of GRB 081203B with the VLA
  23. GRB081203A: Radio upper limit at 15 GHz
  24. GRB 081204B: Fermi GBM detection
  25. GRB 081204: Swift/UVOT Upper Limits
  26. GRB 081204: Swift XRT afterglow confirmation
  27. GRB081203A: MITSuME optical observation
  28. GRB081203A: optical observation
  29. GRB 081204 : a long GRB localized by INTEGRAL
  30. VLA Radio upper limit on GRB 081203A
  31. Swift-XRT observations of GRB 081203B
  32. GRB081203A: Swift-XRT refined analysis
  33. GRB 081203B: optical observations
  34. Swift/UVOT detection of GRB081203B
  35. GRB 081203B: Swift-XRT candidate afterglow.
  36. GRB 081203A: optical observations
  37. GRB081203A: Swift/UVOT grism redshift
  38. GRB 081203A: Burst detection from Swift-BAT slew data
  39. GRB 081203A: Swift-BAT refined analysis
  40. GRB 081203: Enhanced Swift-XRT position
  41. GRB 081130B: MASTER prompt optical observations
  42. GRB081203: optical observation
  43. GRB 081203: Swift detection of a burst with a bright optical counterpart
  44. GRB 081130B: Fermi GBM detection
  45. GRB 081130: Fermi GBM detection
  46. Swift Trigger 335971: Swift/UVOT Observations
  47. GRB 081126: afterglow photometry
  48. GRB 081126: Fermi GBM detection
  49. VLA Radio upper limit on GRB 081126
  50. GRB 081129: Fermi GBM detection
  51. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  52. GRB 081128A: optical observations
  53. Trigger 335971: Swift possible detection of a burst
  54. GRB081128: Swift/UVOT Upper Limits
  55. GRB 081122B: Fermi GBM Detection
  56. GRB 081128: Swift-XRT refined analysis
  57. GRB 081128: Liverpool Telescope afterglow confirmation
  58. GRB081128: optical observations
  59. GRB 081128: Swift-BAT refined analysis
  60. GRB 081128: Enhanced Swift-XRT position
  61. GRB 081128: Optical observation of xinglong TNT
  62. GRB 081128: Swift detection of a burst
  63. GRB081126: Afterglow photometry from Crni Vrh
  64. GRB 081126: GRT Optical Observation
  65. GRB 081127: Swift/UVOT Upper Limits
  66. GRB 081127: Swift-XRT refined analysis
  67. GRB 081127: Enhanced Swift-XRT position
  68. GRB 081127: Swift-BAT refined analysis
  69. GRB 081126: Swift-XRT refined analysis
  70. GRB 081127: Swift detection of a burst
  71. GRB 081126: Swift/UVOT Observations
  72. GRB 081126: optical observations
  73. GRB 081126: Swift-BAT refined analysis
  74. GRB 081126: Enhanced Swift-XRT position
  75. GRB 081126: TAROT Calern observatory optical observations
  76. GRB 081126: Swift detection of a burst
  77. GRB 081125: Fermi GBM detection
  78. GRB 081124: Fermi GBM detection
  79. GRB 081120: Fermi GBM detection
  80. GRB 081118: Fermi GBM detection.
  81. GRB 081122: Fermi GBM detection
  82. GRB 081121, SMARTS optical/IR afterglow observations
  83. Fermi GBM detection of a weak source
  84. GRB081121: Refined Swift/UVOT observations
  85. GRB 081121: Swift-XRT refined analysis
  86. GRB 081121: Enhanced Swift-XRT position
  87. GRB 081121: GROND observations
  88. GRB 081121: Swift-BAT refined analysis
  89. GRB081121: Swift/UVOT observations
  90. GRB 081121: ROTSE-III Detection of Optical Counterpart
  91. GRB081118 : optical upper limit
  92. GRB 081119: Fermi GBM detection
  93. VLA Radio upper limit on GRB 081118
  94. GRB 081118: Swift-XRT refined analysis
  95. GRB 081118: GROND detection of afterglow
  96. GRB 081118: optical afterglow candidate
  97. GRB 081118: Swift UVOT Upper Limits
  98. GRB 081118: Swift-BAT refined analysis
  99. GRB 081118: Enhanced Swift-XRT position
  100. GRB 081118: Swift detection of a burst

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