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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"

17810 results found.

  1. GRB 091202: Swift/UVOT Upper Limits
  2. GRB 091202 - UVOT-enhanced XRT position
  3. GRB 091127: Zadko Telescope Observations
  4. GRB 091202: TAROT Calern observatory optical observations
  5. GRB 091117: Chandra Observations
  6. GRB 091130B: Swift/UVOT Upper Limits
  7. GRB 091127: Skynet/PROMPT Observations of Fading
  8. GRB 091130B: Enhanced Swift-XRT position
  9. GRB 091130B: Swift detection of a burst
  10. GRB 091127: Radio observations
  11. GRB 091127: TAROT La Silla observatory optical observations
  12. GRB 091127: LABOCA/APEX submm observations
  13. GRB 091127: Further NOT optical observations
  14. GRB 091127: Fermi GBM detection
  15. GRB 091127: MASTER early optical transient polarimetry
  16. GRB 091127: Swift-XRT afterglow detection and analysis
  17. GRB 091127: TAROT La Silla observatory optical decay
  18. GRB 091127: Swift/UVOT observations
  19. GRB 091127: NOT observations
  20. GRB 091127 : GROND observations
  21. GRB 091127: REM NIR afterglow detection
  22. GRB 091117: TNG optical observations
  23. GRB 091117A: Swift/UVOT followup observations
  24. GRB 091117: Evidence for Variability of XRT Source #1
  25. GRB091117: Gemini South Observations
  26. GRB 091117: Swift XRT refined analysis
  27. GRB091111: Swift XRT refined analysis
  28. GRB 091031: Fermi LAT detection of a faint burst
  29. GRB 091111: BOOTES-3 contemporaneous imaging
  30. GRB 091111: BOOTES-3 observations
  31. GRB 091109A: GROND and VLT observations
  32. GRB 091109B: Swift/UVOT Upper Limits
  33. GRB 091109B: Enhanced Swift-XRT position
  34. GRB 091109B: Optical limits from Watcher
  35. GRB 091109B: ROTSE-III Optical Limits
  36. GRB 091109B: Swift detection of a short burst
  37. GRB 091109: BOOTES-3 observations
  38. GRB 091109: Swift/UVOT observations
  39. GRB 091109: Faulkes Telescope South observations
  40. GRB 091109: Enhanced Swift-XRT position
  41. GRB091109: REM detection of the NIR afterglow
  42. GRB 091109: Swift detection of a burst with optical afterglow
  43. GRB 091029: Observations from Stardome Observatory
  44. GRB 091104: Swift/UVOT Upper Limits
  45. GRB 091104: Enhanced Swift-XRT position
  46. GRB 091104: Swift detection of a burst
  47. GRB 091102: LABOCA/APEX submm observations
  48. Fermi LAT Upper Limits on GRB 091010
  49. GRB 091102 : Faulkes Telescope South Upper Limits
  50. GRB 091102: Swift/UVOT Upper Limits
  51. GRB 091102: GROND Upper Limits
  52. GRB 091102: BOOTES-3 observations
  53. GRB 091102: Swift/XRT localization
  54. GRB 091024: optical observations
  55. GRB 091024: Fermi LAT upper limits
  56. GRB 091018, SMARTS optical/IR afterglow observations
  57. GRB091029: Swift/UVOT observations
  58. GRB 091029: Enhanced Swift-XRT position
  59. GRB091024 optical observations
  60. GRB 091029: GROND Detection of the Optical/NIR Afterglow
  61. GRB 091029: Swift detection of a burst with an optical counterpart
  62. GRB 091026: Suzaku WAM observation of the prompt emission
  63. GRB 091026: GROND Upper Limits
  64. Radio afterglow detection from GRB 091020
  65. GRB 091026: Swift/UVOT Upper Limits
  66. GRB 091026: Enhanced Swift-XRT position
  67. GRB 091026: Swift detection of a Gamma Ray Burst
  68. GRB091024 Swift/UVOT Upper Limits
  69. GRB 091024: Super-LOTIS early observations
  70. GRB091024: VRcIc Afterglow Observations
  71. GRB 091024: Fermi GBM Observations
  72. GRB 091024: Swift-XRT team refined analysis
  73. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  74. GRB 091024: GRAS004 optical observations
  75. GRB091020 Swift/UVOT observations
  76. GRB 091020: Enhanced Swift-XRT position
  77. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  78. GRB 091020: Swift detection of a burst with an optical afterglow
  79. GRB 091018: Skynet/PROMPT Observations of Fading
  80. GRB 091018 : Faulkes Telescope South Observations
  81. GRB091018: Swift/UVOT observations
  82. GRB 091018: Enhanced Swift-XRT position
  83. GRB 091018: Swift detection of a burst with optical afterglow
  84. GRB 091010: optical obsevation
  85. GRB 091010: Swift-XRT refined analysis
  86. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  87. Radio observation of GRB090927 with ATCA
  88. Radio observation of GRB090926a with ATCA
  89. Radio observation of GRB080916c with ATCA
  90. GRB 091010: Enhanced XRT position
  91. GRB 091010 optical upper limits
  92. GRB 091010: GROND afterglow candidate
  93. GRB 091010: Swift/UVOT Upper Limits
  94. GRB 090904A: afterglow confirmation
  95. GRB 090812: Skynet/PROMPT and GORT Observations
  96. GRB 091003: WHT ACAM observations
  97. GRB 091003: Swift/UVOT Detection of an Optical Afterglow
  98. GRB 091003: UVOT-enhanced XRT position
  99. GRB 091003: Swift UVOT Detection of a Candidate UV Afterglow
  100. GRB 091003A: Fermi LAT detection

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