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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 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
  2. GRB 090820B: Fermi GBM detection
  3. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  4. GRB 090820: MASTER-Net optical polarization observations
  5. GRB 090820: Fermi GBM Detection of a bright burst.
  6. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  7. GRB 090817: Liverpool Telescope Observations
  8. GRB 090817: optical upper limit
  9. GRB 090817: Confirmation of the X-ray afterglow
  10. GRB 090815C: Swift refined analysis
  11. GRB 090817: Fermi GBM observation
  12. GRB 090817: Swift/UVOT Upper Limits
  13. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  14. GRB 090813: I-band observations from 1.5m OSN telescope
  15. GRB 090817: Swift-XRT observations
  16. GRB 090814A: optical observations
  17. GRB 090813: Suzaku WAM observation of the prompt emission
  18. GRB 090812: Suzaku WAM observation of the prompt emission
  19. GRB 090817: a long GRB localized by INTEGRAL
  20. VLA radio non-detection of GRB 090812
  21. GRB 090815B: Fermi GBM detection
  22. GRB 090815: Fermi GBM detection
  23. GRB 090813: CrAO optical obsevations
  24. GRB 090814B: Confirmation of the X-ray afterglow
  25. GRB090814A: NOT optical follow-ups
  26. GRB 090814B: I-band observations from 1.23m CAHA telescope
  27. GRB 090814B: Swift/UVOT Upper Limits
  28. GRB 090814B: Liverpool Telescope Observations
  29. Fermi Gamma-ray Burst Monitor trigger 271934815 is not a GRB
  30. GRB 090814C: Fermi GBM detection
  31. GRB 090814B: Swift-XRT detection of a possible afterglow.
  32. GRB 090814A: Swift/UVOT Observations
  33. GRB 090814A: Swift-XRT Team Refined Analysis
  34. GRB 090814A, RIMOTS optical upper limits
  35. GRB 090814A: Swift-BAT refined analysis
  36. GRB 090813: correction to GCN 9787
  37. GRB090814A: VLT spectroscopy
  38. GRB 090814: Enhanced Swift-XRT position
  39. GRB 090814B: a long GRB localized by INTEGRAL
  40. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  41. GRB 090814: Swift detection of a burst
  42. GRB 090813: Fermi GBM observation
  43. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  44. GRB 090813: Swift-XRT refined analysis
  45. Fermi Gamma-ray Burst Monitor trigger 271833016 is not a GRB
  46. GRB 090813, Swift-BAT refined analysis
  47. Konus-Wind observations of GRB090813
  48. GRB090813: Swift/UVOT upper limits
  49. GRB 090813: Enhanced Swift-XRT position
  50. GRB 090813: Liverpool Telescope afterglow confirmation
  51. GRB 090813: P60 Optical Afterglow Confirmation
  52. GRB 090813: optical candidate from 1.23m CAHA telescope
  53. GRB 090813: Swift detection of a burst
  54. GRB 090812: WIRO NIR upper limit
  55. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  56. GRB 090812: RAPTOR detections during the burst
  57. GRB 090812: Swift XRT refined analysis
  58. GRB 090812, RIMOTS optical upper limits
  59. GRB 090812 Swift-BAT Refined Analysis
  60. GRB090812: Swift/UVOT observations
  61. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  62. GRB 090812: Enhanced Swift-XRT position
  63. GRB 090812 VLT redshift
  64. GRB 090812: Liverpool Telescope afterglow confirmation
  65. GRB 090812: P60 Confirmation of Optical Afterglow
  66. GRB 090812: Swift detection of a burst with an optical counterpart
  67. GRB 090807B: Fermi GBM detection
  68. GRB 090809: Further NOT optical observations
  69. VLA radio upper limit on GRB 090809
  70. GRB 090621B: MAGIC telescope GeV observation
  71. GRB 090621A: MAGIC telescope GeV observation
  72. GRB 090809: WHT observations
  73. GRB 090809 X-shooter redshift
  74. GRB 090809B: Fermi GBM detection
  75. GRB 090809: Swift-XRT refined analysis
  76. GRB090809: Swift/UVOT observations
  77. GRB 090809: Enhanced Swift-XRT position
  78. GRB 090809: Swift-BAT refined analysis
  79. GRB 090809: afterglow confirmation at the NOT
  80. GRB 090809: Swift detection of a burst with a possible optical counterpart
  81. GRB 090807: Liverpool Telescope observations
  82. GRB 090807: MITSuME optical upper limit
  83. GRB 090807: Swift/UVOT Upper Limits
  84. GRB 090807: Swift-XRT refined analysis
  85. GRB 090807, Swift-BAT refined analysis
  86. GRB 090807: Enhanced Swift-XRT position
  87. GRB 090807, RIMOTS optical upper limits
  88. GRB 090807: Swift detection of a burst
  89. Fermi Gamma-ray Burst Monitor trigger 271275771 is not a GRB
  90. GRB 090802B: Fermi GBM detection
  91. IPN Triangulation and Konus-Wind observaions of GRB090727B
  92. GRB 090802: Fermi GBM detection
  93. GRB 090726: optical observation
  94. Swift-BAT trigger 358760 is most likely not a GRB
  95. Swift trigger 358760 is probably a noise event
  96. GRB 090717A: Suzaku WAM observation of the prompt emission
  97. GRB 090709A : Quick look analysis of the Suzaku observation
  98. GRB 090728: Swift-BAT refined analysis
  99. GRB 090727: GRT Optical Observation
  100. GRB 090728: Swift XRT refined analysis

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