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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"

23410 results found.

  1. GRB 090902B: GROND NIR Afterglow Observations
  2. GRB 090902B: Enhanced Swift-XRT position
  3. GRB090902B: Swift/UVOT observations
  4. GRB 090902B: Swift/XRT Afterglow Candidate
  5. GRB 090902B: Fermi LAT detection
  6. GRB 090902B: Fermi GBM detection of a bright burst
  7. GRB 090902: Fermi GBM detection
  8. GRB 090831A: IPN Triangulation
  9. GRB 090831C: GROND upper limits
  10. Swift Trigger 361477, called GRB090831B, is probably not real.
  11. GRB090831C: Swift/UVOT upper limits
  12. GRB 090831B: MITSuME optical upper limits
  13. GRB 090829B: Fermi GBM Detection
  14. GRB 090831C: Enhanced Swift-XRT position
  15. GRB 090831C: Swift detection of a burst
  16. GRB 090831B, RIMOTS optical upper limits
  17. GRB 090831: MAXI GSC detection
  18. GRB 090831B: Swift detection of a possible burst
  19. GRB 090831: Fermi GBM detection
  20. GRB090829: Fermi GBM Detection
  21. GRB 090827: Swift XRT and UVOT observations
  22. GRB 090827 Burst discovered in BAT ground analysis
  23. GRB 090826: Fermi GBM detection
  24. GRB 090828: Fermi GBM detection
  25. GRB 090817 - TLS Observations
  26. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  27. GRB 090823 Long burst with IPN triangulation and BAT position
  28. GRB 090820B: Fermi GBM detection
  29. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  30. GRB 090820: MASTER-Net optical polarization observations
  31. GRB 090820: Fermi GBM Detection of a bright burst.
  32. GRB 090817: optical upper limit
  33. GRB 090817: Confirmation of the X-ray afterglow
  34. GRB 090815C: Swift refined analysis
  35. GRB 090817: Swift/UVOT Upper Limits
  36. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  37. GRB 090817: Swift-XRT observations
  38. GRB 090814A: optical observations
  39. VLA radio non-detection of GRB 090812
  40. GRB 090815B: Fermi GBM detection
  41. GRB 090815: Fermi GBM detection
  42. GRB 090813: CrAO optical obsevations
  43. GRB090814A: NOT optical follow-ups
  44. GRB 090814B: I-band observations from 1.23m CAHA telescope
  45. GRB 090814B: Swift/UVOT Upper Limits
  46. GRB 090814C: Fermi GBM detection
  47. GRB 090814B: Swift-XRT detection of a possible afterglow.
  48. GRB 090814A: Swift/UVOT Observations
  49. GRB 090814A: Swift-XRT Team Refined Analysis
  50. GRB 090814A, RIMOTS optical upper limits
  51. GRB 090814A: Swift-BAT refined analysis
  52. GRB090814A: VLT spectroscopy
  53. GRB 090814: Enhanced Swift-XRT position
  54. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  55. GRB 090814: Swift detection of a burst
  56. GRB090813: Swift/UVOT upper limits
  57. GRB 090813: Enhanced Swift-XRT position
  58. GRB 090813: P60 Optical Afterglow Confirmation
  59. GRB 090813: Swift detection of a burst
  60. GRB 090812: WIRO NIR upper limit
  61. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  62. GRB 090812: RAPTOR detections during the burst
  63. GRB 090812, RIMOTS optical upper limits
  64. GRB 090812 Swift-BAT Refined Analysis
  65. GRB090812: Swift/UVOT observations
  66. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  67. GRB 090812: Enhanced Swift-XRT position
  68. GRB 090812: P60 Confirmation of Optical Afterglow
  69. GRB 090812: Swift detection of a burst with an optical counterpart
  70. GRB 090807B: Fermi GBM detection
  71. GRB 090809: Further NOT optical observations
  72. VLA radio upper limit on GRB 090809
  73. GRB 090809: WHT observations
  74. GRB 090809B: Fermi GBM detection
  75. GRB090809: Swift/UVOT observations
  76. GRB 090809: Enhanced Swift-XRT position
  77. GRB 090809: Swift-BAT refined analysis
  78. GRB 090809: afterglow confirmation at the NOT
  79. GRB 090809: Swift detection of a burst with a possible optical counterpart
  80. GRB 090807: MITSuME optical upper limit
  81. GRB 090807: Swift/UVOT Upper Limits
  82. GRB 090807: Enhanced Swift-XRT position
  83. GRB 090807, RIMOTS optical upper limits
  84. GRB 090807: Swift detection of a burst
  85. GRB 090802B: Fermi GBM detection
  86. IPN Triangulation and Konus-Wind observaions of GRB090727B
  87. GRB 090802: Fermi GBM detection
  88. GRB 090726: optical observation
  89. Swift trigger 358760 is probably a noise event
  90. GRB 090727: GRT Optical Observation
  91. GRB 090726: GRT Optical Observation
  92. GRB 090727: Swift/UVOT Upper Limits
  93. GRB 090728: Swift/UVOT Upper Limits
  94. GRB 090728: Enhanced Swift-XRT position
  95. GRB 090728, RIMOTS optical upper limits
  96. GRB 090728: Swift detection of a burst
  97. GRB 090727: Enhanced Swift-XRT position
  98. GRB 090715B: Late-time Lick 3m observations
  99. GRB 090727: Swift detection of a burst
  100. GRB090726: Swift/UVOT observations

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