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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 091024: Keck/LRIS Spectroscopy
  2. GRB 091024: YNAO-GMG observations
  3. GRB 091026: GROND Upper Limits
  4. GRB 091020: Late TLS detection
  5. GRB 091026: Swift-BAT refined analysis
  6. Radio afterglow detection from GRB 091020
  7. GRB 091026: Swift/UVOT Upper Limits
  8. GRB 091024: Burst was outside the Swift-BAT FOV after T0(BAT)+460sec
  9. GRB 091026: Swift-XRT refined analysis
  10. GRB 091026: Enhanced Swift-XRT position
  11. Konus-Wind and Konus-RF observations of GRB 091024
  12. GRB 091026: Updated Swift-XRT position
  13. GRB 091026: Swift detection of a Gamma Ray Burst
  14. GRB 091020 : Xinglong TNT upper limit
  15. Swift-BAT Triggers 373776-373778 are not real
  16. GRB091024 Swift/UVOT Upper Limits
  17. GRB 091024: TLS Upper Limit
  18. GRB 091020: Early TLS Multicolor detections, red afterglow
  19. GRB 091024: KAIT optical afterglow observations
  20. GRB 091024: Super-LOTIS early observations
  21. GRB091024: VRcIc Afterglow Observations
  22. GRB 091024: Swift-BAT refined analysis
  23. Swift-BAT Triggers 373679-373684 are not real
  24. GRB 091024: Fermi GBM Observations
  25. GRB 091024: Swift-XRT team refined analysis
  26. Swift-BAT trigger 373691 is a galactic bulge transient
  27. GRB 091024: Xinglong TNT optical observation
  28. GRB 091024 : Faulkes Telescope North - Afterglow Confirmation
  29. GRB 091024 Gemini-North redshift
  30. GRB 091024: GRAS004 optical observations
  31. GRB 091024: Faulkes Telescope North Afterglow Candidate
  32. GRB 091024: Swift detection of a burst
  33. GRB 091018: Skynet/PROMPT Continued Observations of Fading
  34. GRB 091020: Additional Lick observations
  35. Konus-Wind observations of GRB 091020 (correction to GCN 10057)
  36. GRB 091020: Lick observations
  37. Konus-Wind observations of GRB 091010
  38. GRB 091020: Swift-XRT refined analysis
  39. GRB 091018: Swift XRT refined analysis
  40. GRB091020 Swift/UVOT observations
  41. GRB 091020: NOT spectroscopic redshift
  42. GRB 091020: MASTER optical transient polarimetry
  43. GRB 091020, Swift-BAT refined analysis
  44. GRB 091020: Enhanced Swift-XRT position
  45. GRB 090926A: Late-time Gemini South Observations and Possible Jet Break
  46. GRB 091020: Swift detection of a burst with an optical afterglow
  47. GRB 091018: miniTAO/ANIR Observations
  48. GRB 091018: Skynet/PROMPT Observations of Fading
  49. Konus-RF observation of GRB 091018
  50. GRB 091018 : Faulkes Telescope South Observations
  51. GRB 091018: BOOTES-3 observations
  52. GRB 091018: VLT/X-shooter spectra
  53. GRB091018: Swift/UVOT observations
  54. GRB 091018: Swift-BAT refined analysis
  55. GRB 091018: GROND observations
  56. GRB091018: Magellan Echellette Observations
  57. GRB 091018: Enhanced Swift-XRT position
  58. GRB 091018: ROTSE-III Detection of Optical Counterpart
  59. GRB 091015: Skynet/PROMPT Observations
  60. GRB 091018: Swift detection of a burst with optical afterglow
  61. Fwd: GRB 091003: Possible Supernova Component Retraction
  62. GRB 091003: Possible Supernova Component
  63. GRB 091003: Gemini-N redshift of possible host galaxy
  64. GRB 091010: optical obsevation
  65. GRB 091015: RTT150 optical observations
  66. GRB 090726 R band observations
  67. GRB 091010: optical afterglow candidate rejection
  68. GRB 091015: correction to GCN 10025
  69. GRB 090815: a faint long GRB localized by INTEGRAL
  70. GRB 091010: Swift-XRT refined analysis
  71. GRB 091010: Suzaku WAM observation of the prompt emission
  72. GRB 091010: AGILE-MCAL measurement and GRID upper limit
  73. Radio observation of GRB090927 with ATCA
  74. Radio observation of GRB090926a with ATCA
  75. Radio observation of GRB080916c with ATCA
  76. GRB 091010: Fermi GBM observation
  77. GRB 091010: Faulkes Telescope North observations
  78. GRB 090531A: Skynet/PROMPT Observations
  79. GRB 090530A: Skynet/DSO Detections
  80. GRB 091010: RXTE detection
  81. Konus-Wind observations of GRB 091010
  82. GRB 091010: Enhanced XRT position
  83. GRB 091010 optical upper limits
  84. Detection of a short GRB 090929A by RT-2 Experiment
  85. RT-2 observation of the bright GRB 090926A
  86. GRB 091010: GROND afterglow candidate
  87. GRB 091010: Swift/UVOT Upper Limits
  88. GRB 091010: Swift-XRT position
  89. SuperAGILE GRB is 091010 and not 090910
  90. GRB 090910: SuperAGILE Localization of a Long GRB
  91. GRB 090926A: Skynet/PROMPT Observations of Day 6 - 11 Fading
  92. GRB 090518: Skynet/PROMPT Observations
  93. Short-Duration GRB 090621: Skynet/Dolomiti Observations
  94. GRB 090904A: afterglow confirmation
  95. GRB 090812: Skynet/PROMPT and GORT Observations
  96. GRB 091003A: Suzaku WAM observation of the prompt emission
  97. GRB 091003: Lick observations and possible SDSS host galaxy
  98. GRB 090926B: Skynet/PROMPT Observations
  99. GRB 091003: WHT ACAM observations
  100. Konus-Wind observation of GRB 091003A

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