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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"

15743 results found.

  1. GRB 091018, SMARTS optical/IR afterglow observations
  2. GRB091029: Swift/UVOT observations
  3. GRB 091029: Skynet/PROMPT Continued Observations of Fading
  4. GRB091024 optical observations
  5. GRB 091029: Gemini-South Redshift
  6. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  7. GRB 091029: Swift detection of a burst with an optical counterpart
  8. GRB 091024: Keck/LRIS Spectroscopy
  9. GRB 091024: YNAO-GMG observations
  10. GRB 091026: Swift/UVOT Upper Limits
  11. Konus-Wind and Konus-RF observations of GRB 091024
  12. GRB 091020 : Xinglong TNT upper limit
  13. GRB091024 Swift/UVOT Upper Limits
  14. GRB 091024: KAIT optical afterglow observations
  15. GRB 091024: Super-LOTIS early observations
  16. GRB091024: VRcIc Afterglow Observations
  17. GRB 091024: Swift-XRT team refined analysis
  18. GRB 091024: Xinglong TNT optical observation
  19. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  20. GRB 091024: GRAS004 optical observations
  21. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  22. GRB091020 Swift/UVOT observations
  23. GRB 091020: NOT spectroscopic redshift
  24. GRB 091020: MASTER optical transient polarimetry
  25. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  26. GRB 091020: Swift detection of a burst with an optical afterglow
  27. GRB 091018: ROTSE-III Detection of Optical Counterpart
  28. GRB 091018: Swift detection of a burst with optical afterglow
  29. GRB 091003: Possible Supernova Component
  30. GRB 091010: optical obsevation
  31. GRB 091015: RTT150 optical observations
  32. GRB 091010: optical afterglow candidate rejection
  33. GRB 091010: Enhanced XRT position
  34. GRB 091010 optical upper limits
  35. GRB 091010: Swift/UVOT Upper Limits
  36. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  37. GRB 090904A: afterglow confirmation
  38. GRB 090812: Skynet/PROMPT and GORT Observations
  39. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  40. GRB 090926A: Skynet/PROMPT Observations of Day 4 - 6 Fading Rate
  41. GRB 090926A: Skynet/PROMPT Observations of Post-Peak Fading
  42. GRB 090929B: Swift/UVOT Observations
  43. GRB 090929B: RAPTOR Discovery of Optical Counterpart
  44. GRB 090927: Faulkes Telescope South Detection of the Optical Afterglow
  45. GRB 090927: VLT redshift
  46. GRB 090927: Zadko Telescope observations
  47. Swift/UVOT observations of GRB 090927
  48. GRB 090926A: Skynet/PROMPT Continued Observations
  49. GRB090926A: Swift/UVOT observations
  50. GRB 090926B: VLT spectroscopy
  51. GRB 090927: Swift/UVOT detection of an optical afterglow
  52. GRB 090926B: optical object in error circle
  53. GRB 090926B: NOT optical observation
  54. GRB 090926A: Swift/UVOT detection of an optical afterglow
  55. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  56. GRB 090912: optical observation
  57. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  58. GRB 090912: Swift/UVOT Upper Limits
  59. GRB 090912 optical upper limit
  60. GRB 090814A: Skynet/DSO & GORT Observations
  61. GRB 090904B: GROND detection of the optical afterglow
  62. GRB 090904B: MOA-II Optical observation
  63. GRB 090904A: NOT observations
  64. GRB 090902B: WSRT Radio Observation
  65. GRB090904B: REM observations
  66. GRB 090904A: ROTSE-III Optical Limits
  67. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  68. GRB 090902B: Swift/UVOT refined analysis
  69. GRB 090902B: GROND NIR Afterglow Observations
  70. GRB 090902B: Optical afterglow candidate
  71. GRB 090831B: MITSuME optical upper limits
  72. GRB 090831B, RIMOTS optical upper limits
  73. GRB 090823: Swift XRT possible detection of the X-ray afterglow
  74. GRB 090820: MASTER-Net optical polarization observations
  75. GRB 090817: optical upper limit
  76. GRB 090813: I-band observations from 1.5m OSN telescope
  77. GRB 090817: Swift-XRT observations
  78. GRB 090814A: optical observations
  79. VLA radio non-detection of GRB 090812
  80. GRB 090813: CrAO optical obsevations
  81. GRB090814A: NOT optical follow-ups
  82. GRB 090814B: I-band observations from 1.23m CAHA telescope
  83. GRB 090814B: Swift/UVOT Upper Limits
  84. GRB 090814A: Swift/UVOT Observations
  85. GRB 090814A, RIMOTS optical upper limits
  86. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  87. GRB090813: Swift/UVOT upper limits
  88. GRB 090813: Liverpool Telescope afterglow confirmation
  89. GRB 090813: P60 Optical Afterglow Confirmation
  90. GRB 090813: optical candidate from 1.23m CAHA telescope
  91. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  92. GRB 090812: RAPTOR detections during the burst
  93. GRB 090812: Swift XRT refined analysis
  94. GRB 090812, RIMOTS optical upper limits
  95. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  96. GRB 090812: Liverpool Telescope afterglow confirmation
  97. GRB 090812: P60 Confirmation of Optical Afterglow
  98. GRB 090812: Swift detection of a burst with an optical counterpart
  99. GRB 090809: Further NOT optical observations
  100. VLA radio upper limit on GRB 090809

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