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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"

21206 results found.

  1. GRB 090927: Enhanced Swift-XRT position
  2. GRB090926B: Swift/UVOT Upper Limits
  3. GRB090926A: Swift/UVOT observations
  4. GRB 090926B: optical object in error circle
  5. GRB 090926B: NOT optical observation
  6. GRB 090926B: Swift XRT refined analysis
  7. GRB 090926A: Swift/UVOT detection of an optical afterglow
  8. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  9. GRB090926A: UVOT-enhanced XRT position
  10. GRB 090926B: Swift detection of a burst
  11. GRB 090926: Fermi LAT detection
  12. GRB 090715B: Skynet/PROMPT Detections
  13. GRB 090916: Swift-XRT upper limit
  14. GRB 090915: GROND upper limits
  15. Short-Duration GRB 090916: Skynet/PROMPT Observations
  16. GRB 090915: SARA detection of afterglow candidate
  17. GRB 090912: optical observation
  18. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  19. GRB 090902B: Skynet/PROMPT Observations
  20. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  21. GRB 090915 Swift-BAT detection of a burst in ground analysis
  22. GRB 090827: Confirmation of the X-ray afterglow
  23. GRB 090912: Swift/UVOT Upper Limits
  24. GRB 090912 optical upper limit
  25. GRB 090912: Enhanced Swift-XRT position
  26. GRB 090912: Swift detection of a burst
  27. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  28. GRB 090904B: GROND detection of the optical afterglow
  29. GRB 090831A: Suzaku WAM observation of the prompt emission
  30. GRB 090904B: Swift/UVOT Refined Analysis
  31. GRB 090902B: Suzaku WAM observation of the prompt emission
  32. GRB 090829A: Suzaku WAM observation of the prompt emission
  33. GRB 090904A: Enhanced Swift XRT position
  34. GRB 090904B: Swift-BAT refined analysis
  35. GRB 090902B: VLA radio detection
  36. GRB 090904A: Swift-BAT refined analysis
  37. GRB 090904B: Enhanced Swift-XRT position
  38. GRB 090904A: Enhanced Swift-XRT position
  39. GRB 090904A: NOT observations
  40. GRB090904B: REM observations
  41. GRB 090904B: Swift detection of a burst
  42. GRB 090904A: ROTSE-III Optical Limits
  43. GRB 090904: Swift detection of a burst
  44. GRB 090902B: Swift/UVOT refined analysis
  45. GRB 090902B: GROND NIR Afterglow Observations
  46. GRB 090902B: Enhanced Swift-XRT position
  47. GRB090902B: Swift/UVOT observations
  48. GRB 090902B: Swift/XRT Afterglow Candidate
  49. GRB 090902B: Fermi LAT detection
  50. GRB 090831C: GROND upper limits
  51. Konus-Wind observations of GRB 090831A
  52. Swift Trigger 361477, called GRB090831B, is probably not real.
  53. GRB090831C: Swift/UVOT upper limits
  54. GRB 090831B: MITSuME optical upper limits
  55. GRB 090831C: Enhanced Swift-XRT position
  56. GRB 090831C: Swift detection of a burst
  57. GRB 090831B, RIMOTS optical upper limits
  58. GRB 090831B: Swift detection of a possible burst
  59. GRB 090827: Swift XRT and UVOT observations
  60. GRB 090828: Fermi GBM detection
  61. GRB 090817 - TLS Observations
  62. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  63. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  64. GRB 090820: MASTER-Net optical polarization observations
  65. GRB 090820: Fermi GBM Detection of a bright burst.
  66. GRB 090817: optical upper limit
  67. GRB 090817: Confirmation of the X-ray afterglow
  68. GRB 090817: Swift/UVOT Upper Limits
  69. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  70. GRB 090817: Swift-XRT observations
  71. GRB 090814A: optical observations
  72. GRB 090813: Suzaku WAM observation of the prompt emission
  73. GRB 090812: Suzaku WAM observation of the prompt emission
  74. VLA radio non-detection of GRB 090812
  75. GRB 090813: CrAO optical obsevations
  76. GRB090814A: NOT optical follow-ups
  77. GRB 090814B: I-band observations from 1.23m CAHA telescope
  78. GRB 090814B: Swift/UVOT Upper Limits
  79. GRB 090814B: Swift-XRT detection of a possible afterglow.
  80. GRB 090814A: Swift/UVOT Observations
  81. GRB 090814A, RIMOTS optical upper limits
  82. GRB090814A: VLT spectroscopy
  83. GRB 090814: Enhanced Swift-XRT position
  84. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  85. GRB 090814: Swift detection of a burst
  86. GRB090813: Swift/UVOT upper limits
  87. GRB 090813: Enhanced Swift-XRT position
  88. GRB 090813: P60 Optical Afterglow Confirmation
  89. GRB 090813: Swift detection of a burst
  90. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  91. GRB 090812: RAPTOR detections during the burst
  92. GRB 090812, RIMOTS optical upper limits
  93. GRB 090812 Swift-BAT Refined Analysis
  94. GRB090812: Swift/UVOT observations
  95. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  96. GRB 090812: Enhanced Swift-XRT position
  97. GRB 090812: P60 Confirmation of Optical Afterglow
  98. GRB 090812: Swift detection of a burst with an optical counterpart
  99. GRB 090807B: Fermi GBM detection
  100. GRB 090809: Further NOT optical observations

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