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

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