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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. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  2. GRB 090814: Swift detection of a burst
  3. GRB 090813: Fermi GBM observation
  4. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  5. GRB 090813: Swift-XRT refined analysis
  6. Fermi Gamma-ray Burst Monitor trigger 271833016 is not a GRB
  7. GRB 090813, Swift-BAT refined analysis
  8. Konus-Wind observations of GRB090813
  9. GRB090813: Swift/UVOT upper limits
  10. GRB 090813: Enhanced Swift-XRT position
  11. GRB 090813: Liverpool Telescope afterglow confirmation
  12. GRB 090813: P60 Optical Afterglow Confirmation
  13. GRB 090813: optical candidate from 1.23m CAHA telescope
  14. GRB 090813: Swift detection of a burst
  15. GRB 090812: WIRO NIR upper limit
  16. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  17. GRB 090812: RAPTOR detections during the burst
  18. GRB 090812: Swift XRT refined analysis
  19. GRB 090812, RIMOTS optical upper limits
  20. GRB 090812 Swift-BAT Refined Analysis
  21. GRB090812: Swift/UVOT observations
  22. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  23. GRB 090812: Enhanced Swift-XRT position
  24. GRB 090812 VLT redshift
  25. GRB 090812: Liverpool Telescope afterglow confirmation
  26. GRB 090812: P60 Confirmation of Optical Afterglow
  27. GRB 090812: Swift detection of a burst with an optical counterpart
  28. GRB 090807B: Fermi GBM detection
  29. GRB 090809: Further NOT optical observations
  30. VLA radio upper limit on GRB 090809
  31. GRB 090621B: MAGIC telescope GeV observation
  32. GRB 090621A: MAGIC telescope GeV observation
  33. GRB 090809: WHT observations
  34. GRB 090809 X-shooter redshift
  35. GRB 090809B: Fermi GBM detection
  36. GRB 090809: Swift-XRT refined analysis
  37. GRB090809: Swift/UVOT observations
  38. GRB 090809: Enhanced Swift-XRT position
  39. GRB 090809: Swift-BAT refined analysis
  40. GRB 090809: afterglow confirmation at the NOT
  41. GRB 090809: Swift detection of a burst with a possible optical counterpart
  42. GRB 090807: Liverpool Telescope observations
  43. GRB 090807: MITSuME optical upper limit
  44. GRB 090807: Swift/UVOT Upper Limits
  45. GRB 090807: Swift-XRT refined analysis
  46. GRB 090807, Swift-BAT refined analysis
  47. GRB 090807: Enhanced Swift-XRT position
  48. GRB 090807, RIMOTS optical upper limits
  49. GRB 090807: Swift detection of a burst
  50. Fermi Gamma-ray Burst Monitor trigger 271275771 is not a GRB
  51. GRB 090802B: Fermi GBM detection
  52. IPN Triangulation and Konus-Wind observaions of GRB090727B
  53. GRB 090802: Fermi GBM detection
  54. GRB 090726: optical observation
  55. Swift-BAT trigger 358760 is most likely not a GRB
  56. Swift trigger 358760 is probably a noise event
  57. GRB 090717A: Suzaku WAM observation of the prompt emission
  58. GRB 090709A : Quick look analysis of the Suzaku observation
  59. GRB 090728: Swift-BAT refined analysis
  60. GRB 090727: GRT Optical Observation
  61. GRB 090728: Swift XRT refined analysis
  62. GRB 090727: optical observations
  63. GRB 090726: GRT Optical Observation
  64. GRB 090727: Swift/UVOT Upper Limits
  65. GRB 090728: Swift/UVOT Upper Limits
  66. GRB 090728: Enhanced Swift-XRT position
  67. GRB 090727: I-band observations from 1.23m CAHA
  68. GRB 090728, RIMOTS optical upper limits
  69. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  70. GRB 090728: Swift detection of a burst
  71. GRB 090727: Swift-BAT refined analysis
  72. GRB 090727: Swift-XRT refined analysis
  73. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  74. GRB 090727: Enhanced Swift-XRT position
  75. GRB 090715B: Late-time Lick 3m observations
  76. GRB 090727: Liverpool Telescope possible OT candidate
  77. GRB 090727: Swift detection of a burst
  78. GRB090726: Swift/UVOT observations
  79. GRB 090726, Swift-BAT refined analysis
  80. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  81. GRB 090726: D50 optical observations
  82. GRB 090711: Fermi GBM detection
  83. GRB090726: 6-meter telescope redshift
  84. GRB 090726: Swift-XRT Team refined analysis
  85. GRB 090726: Enhanced Swift-XRT position
  86. GRB 090726: optical transient candidate
  87. GRB 090726: Swift/UVOT Finding Chart Observation
  88. GRB 090726: Swift-XRT position of probable counterpart
  89. GRB 090726: Swift detection of a burst
  90. Swift Trigger 358354 is not a GRB
  91. Konus-Wind and Konus-RF observations of GRB 090719
  92. Konus-RF and Konus-Wind observations of GRB 090718B
  93. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  94. Konus-Wind observations of bright hard GRB 090720B
  95. IPN Triangulation of bright GRB 090720B
  96. GRB 090720: Gemini-North Imaging and Optical Afterglow
  97. GRB 090720B: Fermi GBM detection
  98. Swift XRT and UVOT refned analysis of GRB 090720
  99. GRB 090709A: Swift XRT Timing Analysis
  100. GRB 090715B: VLA radio detection

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