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

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