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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 090927: Zadko Telescope observations
  2. GRB 090927, Swift-BAT refined analysis of the possibly short burst
  3. Swift/UVOT observations of GRB 090927
  4. GRB 090926A: Skynet/PROMPT Continued Observations
  5. GRB 090927: Swift XRT refined analysis
  6. GRB 090926A: Suzaku WAM observation of the prompt emission
  7. GRB 090927: Enhanced Swift-XRT position
  8. GRB090926B: Swift/UVOT Upper Limits
  9. GRB090926A: Swift/UVOT observations
  10. GRB 090926B: VLT spectroscopy
  11. GRB 090927: Swift/UVOT detection of an optical afterglow
  12. GRB 090927: Swift detection of a short burst
  13. GRB 090926B: optical object in error circle
  14. GRB 090926B: MAXI GSC detection
  15. GRB 090926A: VLT/X-shooter redshift
  16. GRB 090926B: NOT optical observation
  17. GRB 090926B: Swift XRT refined analysis
  18. GRB 090926B: Swift-BAT refined analysis
  19. GRB 090926A: Swift/UVOT detection of an optical afterglow
  20. GRB 090926A: Skynet/PROMPT Discovery of the Optical Afterglow
  21. GRB090926A: UVOT-enhanced XRT position
  22. GRB 090926B: Swift detection of a burst
  23. GRB 090926: Fermi LAT detection
  24. GRB 090926: Fermi GBM detection
  25. GRB 090925: Fermi GBM detection
  26. GRB090904B : IRSF NIR upper limit
  27. GRB090922A: correction to Fermi location
  28. GRB 090922A: Fermi GBM detection
  29. Swift returns to normal operations
  30. GRB 090715B: Skynet/PROMPT Detections
  31. GRB 090726: Skynet/GORT Observations
  32. GRB 090916: Swift-XRT upper limit
  33. GRB 090807: Skynet/DSO Observations
  34. GRB 090915: GROND upper limits
  35. Swift-BAT temporarily off-line for a few days
  36. Short-Duration GRB 090916: Skynet/PROMPT Observations
  37. GRB 090915: SARA detection of afterglow candidate
  38. GRB 090912: optical observation
  39. GRB 090915: Swift/UVOT detection of an optical afterglow candidate
  40. GRB 090702: Skynet/GORT Observations
  41. GRB 090902B: Skynet/PROMPT Observations
  42. GRB 090916, Swift-BAT refined analysis
  43. GRB 090915: Swift-XRT detection of a fading X-ray counterpart
  44. GRB 090916: Swift detection of a short burst
  45. GRB 090915 Swift-BAT detection of a burst in ground analysis
  46. GRB 090827: Confirmation of the X-ray afterglow
  47. GRB 090912: Swift-XRT refined analysis
  48. GRB 090912, Swift-BAT refined analysis
  49. GRB 090912: Swift/UVOT Upper Limits
  50. GRB 090912 optical upper limit
  51. GRB 090912: Enhanced Swift-XRT position
  52. GRB 090912: Swift detection of a burst
  53. GRB 090910: Fermi GBM detection
  54. GRB 090814A: Skynet/DSO & GORT Observations
  55. GRB 090823: Swift XRT confirmation of the X-ray afterglow
  56. GRB 090904B: GROND detection of the optical afterglow
  57. GRB 090831A: Suzaku WAM observation of the prompt emission
  58. GRB 090904A: Swift/UVOT Refined Analysis
  59. GRB 090904B: Swift/UVOT Refined Analysis
  60. GRB 090902B: Suzaku WAM observation of the prompt emission
  61. GRB 090829A: Suzaku WAM observation of the prompt emission
  62. GRB 090904B: Fermi GBM detection
  63. GRB 090904A: Swift-XRT refined analysis
  64. GRB 090904B: Swift XRT Refined Analysis
  65. GRB 090904B: MOA-II Optical observation
  66. GRB 090904A: Enhanced Swift XRT position
  67. GRB 090904B: Swift-BAT refined analysis
  68. GRB 090902B: VLA radio detection
  69. GRB 090904A: Swift-BAT refined analysis
  70. GRB 090904B: Enhanced Swift-XRT position
  71. GRB090904A: Correction to enhanced XRT position
  72. GRB 090904A: Enhanced Swift-XRT position
  73. GRB 090904A: NOT observations
  74. GRB 090902B: WSRT Radio Observation
  75. GRB090904B: REM observations
  76. GRB 090904B: Swift detection of a burst
  77. GRB 090904A: ROTSE-III Optical Limits
  78. GRB 090904: Swift detection of a burst
  79. GRB 090902B: ROTSE-III Detection of Optical Afterglow
  80. GRB 090902B: Swift/UVOT refined analysis
  81. GRB090902B: Swift XRT refined analysis
  82. GRB 090902B: Faulkes Telescope North observations
  83. GRB 090902B: GROND NIR Afterglow Observations
  84. GRB 090902B: Gemini-N absorption redshift
  85. GRB 090902B: Fermi LAT and GBM refined analysis.
  86. GRB 090902B: Enhanced Swift-XRT position
  87. GRB 090902B: Optical afterglow candidate
  88. GRB090902B: Swift/UVOT observations
  89. GRB 090902B: Swift/XRT Afterglow Candidate
  90. GRB 090902B: Fermi LAT detection
  91. GRB 090902B: Fermi GBM detection of a bright burst
  92. GRB 090902: Fermi GBM detection
  93. GRB 090831A: IPN Triangulation
  94. GRB 090831C BAT refined analysis
  95. GRB 090831C: GROND upper limits
  96. Konus-Wind observations of GRB 090831A
  97. Swift Trigger 361477, called GRB090831B, is probably not real.
  98. GRB090831C: Swift/UVOT upper limits
  99. GRB 090831B: MITSuME optical upper limits
  100. GRB 090831C: Swift XRT Refined Analysis

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