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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 091127: CAHA 1.23m I-band observations
  2. GRB 091127: Swift-BAT refined analysis
  3. GRB 091127: NOT observations
  4. GRB 091127 : GROND observations
  5. GRB 091127: REM NIR afterglow detection
  6. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  7. GRB 091127: Liverpool Telescope afterglow candidate
  8. GRB 091127: Swift detection of a burst
  9. IPN Triangulation of GRB091120
  10. Konus-Wind observation of GRB 091120
  11. GRB 091120: MAXI GSC detection
  12. GRB 091120: Fermi GBM observation
  13. GRB 091117A: Suzaku WAM observation of the prompt emission
  14. GRB 091117: TNG optical observations
  15. GRB 091117A: Swift/UVOT followup observations
  16. GRB 091117: 2nd epoch of Magellan optical observations
  17. GRB 091117: VLA radio observations
  18. GRB 091117: Swift-XRT observations
  19. GRB 091117 BAT refined analysis
  20. GRB 091117: Evidence for Variability of XRT Source #1
  21. GRB091117: Gemini South Observations
  22. GRB 091117: Swift XRT refined analysis
  23. GRB 091117: Gemini-North spectroscopy of DSS galaxy
  24. Konus-Wind observations of GRB 091117A
  25. GRB 091117: Magellan optical observations
  26. GRB 091117: XRT source coincident with a DSS galaxy
  27. GRB 091117: OSN I-band observations
  28. GRB 091117A Detected in ground analysis of BAT data and IPN triangulation
  29. GRB 091112: Suzaku WAM observation of the prompt emission
  30. GRB 091102A: Suzaku WAM observation of the prompt emission
  31. GRB 091109B: Suzaku WAM observation of the prompt emission
  32. GRB091111: Swift XRT refined analysis
  33. Konus-Wind and Konus-RF observations of GRB 091031
  34. GRB 091112: Swift-BAT refined analysis
  35. GRB 091112: Fermi GBM observation
  36. GRB 091031: Fermi LAT detection of a faint burst
  37. GRB 091112: Swift detection of a possible burst
  38. GRB 091111: BOOTES-3 contemporaneous imaging
  39. GRB 091111: BOOTES-3 observations
  40. GRB 091111: a faint long GRB detected with INTEGRAL
  41. GRB 091109A: GROND and VLT observations
  42. GRB 091109B: Swift/UVOT Upper Limits
  43. GRB 091109B: VLT afterglow confirmation
  44. GRB 091109B: Swift-XRT Team refined analysis
  45. GRB 091109B: VLT observations
  46. GRB 091109b: Magellan Observations
  47. GRB 091109B: Swift-BAT refined analysis
  48. GRB 091109B: Enhanced Swift-XRT position
  49. GRB 091109B: Optical limits from Watcher
  50. GRB 091109B: ROTSE-III Optical Limits
  51. GRB 091109B: Swift detection of a short burst
  52. GRB091109: Correction to GCN 10139
  53. GRB 091030: Fermi GBM detection
  54. GRB 091109: Swift-XRT refined analysis
  55. GRB 091109: BOOTES-3 observations
  56. GRB 091109: Swift/UVOT observations
  57. GRB 091109: Faulkes Telescope South observations
  58. GRB 091109: Swift-BAT refined analysis
  59. GRB 091109: Enhanced Swift-XRT position
  60. GRB091109: REM detection of the NIR afterglow
  61. GRB 091109: Swift detection of a burst with optical afterglow
  62. GRB 091029: Observations from Stardome Observatory
  63. GRB 091104: Swift-BAT refined analysis
  64. GRB 091104: Swift XRT Refined Analysis
  65. GRB 091104: Swift/UVOT Upper Limits
  66. GRB091026 : IRSF NIR upper limit
  67. GRB091102 : MOA optical upper limit
  68. GRB 091104: Enhanced Swift-XRT position
  69. GRB 091104: Swift detection of a burst
  70. GRB 091102: LABOCA/APEX submm observations
  71. Fermi LAT Upper Limits on GRB 091010
  72. GRB 091102 : Faulkes Telescope South Upper Limits
  73. GRB 091102A: Fermi GBM observation
  74. GRB 091102: Swift-XRT refined analysis
  75. GRB 091102: Swift/UVOT Upper Limits
  76. GRB 091102: GROND Upper Limits
  77. GRB 091102: BOOTES-3 observations
  78. GRB 091102: Swift-BAT refined analysis
  79. GRB 091102: Swift/XRT localization
  80. GRB 091102: ROTSE-III Optical Limits
  81. GRB 091102: Swift/UVOT Finding Chart Observation
  82. GRB 091102: Swift detection of a burst
  83. GRB 091024: optical observations
  84. GRB 091031: Fermi GBM detection
  85. GRB 091024: Fermi LAT upper limits
  86. GRB 090926a, SMARTS optical/IR afterglow observations
  87. GRB 091018: Skynet/PROMPT Observations of Possible Host Galaxy
  88. GRB 091029, SMARTS optical/IR afterglow observations
  89. GRB 091018, SMARTS optical/IR afterglow observations
  90. GRB 090920: Skynet/DSO Detection
  91. GRB091029: Swift/UVOT observations
  92. GRB 091029: Skynet/PROMPT Continued Observations of Fading
  93. GRB 091029: Swift XRT refined analysis
  94. Fermi Gamma-ray Burst Monitor trigger 091028818 is not a GRB
  95. GRB 091029: BOOTES-3 observations
  96. GRB 091029: Swift-BAT refined analysis
  97. GRB 091029: Enhanced Swift-XRT position
  98. GRB091024 optical observations
  99. GRB 091029: Gemini-South Redshift
  100. GRB 091029: Skynet/PROMPT Observations of Peak and Fading

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