Skip to main content
New! CHIME and DSA-110 FRB Notices, IceCube Notices and Schema v6.1.1. See news and announcements

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. Possible GRB 081211B - Swift-XRT analysis
  2. GRB 081207: Fermi GBM detection
  3. GRB 081209: Fermi GBM detection
  4. Fermi Gamma-ray Burst Monitor trigger 250533995 is not a GRB
  5. GRB 081007: Detection of a Supernova
  6. GRB 081211B(?): Possible burst detection from Swift-BAT slew data
  7. GRB 081210: Xinglong TNT R band Upper Limits
  8. GRB 081210, SMARTS optical/IR observations
  9. GRB 081211: Swift-BAT refined analysis
  10. GRB 081211: Swift XRT refined analysis
  11. GRB 081211: Swift/UVOT detection of an optical afterglow
  12. GRB 081211: Enhanced Swift-XRT position
  13. GRB 081210: Swift/UVOT refined analysis
  14. GRB 081211: Swift detection of a burst
  15. GRB 081210: Swift-XRT refined analysis
  16. GRB081203B: optical observations
  17. GRB 081210: Enhanced Swift-XRT position
  18. GRB 081210: Swift-BAT refined analysis
  19. GRB 081210: Swift detection of a burst with optical afterglow
  20. Konus-Wind observation of GRB 081209
  21. IPN triangulation of short hard GRB 081209
  22. GRB 081203A: optical observations
  23. GRB 081206C: Fermi GBM detection
  24. Radio observation of GRB 081121 with ATCA
  25. Radio observation of GRB 081118 with ATCA
  26. GRB 081206B: Fermi GBM detection
  27. GRB 081206: Fermi GBM detection
  28. GRB 081128: afterglow observations
  29. GRB 081203B: Suzaku WAM observation of the prompt emission
  30. GRB 081203B: Additional Gemini imaging
  31. Radio observation of GRB 081109 with ATCA
  32. Radio observation of GRB 081104 with ATCA
  33. Radio observation of GRB 081029 with ATCA
  34. Radio observation of GRB 081008 with ATCA
  35. GRB081203A: Ashra-1 observation of early optical and VHE-neutrino emission
  36. GRB 081203B: Gemini observations
  37. GRB 081128: optical observation in CrAO
  38. GRB081203A: Optical observations at Ishigaki
  39. GRB 081128: Optical afterglow observations
  40. GRB 081204: GROND Observations
  41. GRB081203B: optical observations
  42. Radio detection of GRB 081203B with the VLA
  43. GRB 081204: Magellan observations
  44. GRB081203A: Radio upper limit at 15 GHz
  45. GRB 081204B: Fermi GBM detection
  46. GRB 081204: Swift/UVOT Upper Limits
  47. GRB 081204: Swift XRT afterglow confirmation
  48. GRB081203A: MITSuME optical observation
  49. GRB 081203A: Optical observations of Xinglong TNT telescope
  50. GRB 081203A: Skynet/GORT Detections
  51. GRB 081204: Swift XRT afterglow candidate
  52. GRB081203A: optical observation
  53. GRB 081204 : a long GRB localized by INTEGRAL
  54. VLA Radio upper limit on GRB 081203A
  55. Swift-XRT observations of GRB 081203B
  56. Konus-Wind observation of GRB 081203A
  57. Konus-Wind observation of GRB 081203B
  58. GRB081203A: Swift-XRT refined analysis
  59. GRB 081203B: optical observations
  60. GRB 081203B: SDSS upper limits at the position of the optical afterglow
  61. Swift/UVOT detection of GRB081203B
  62. GRB 081203B: Swift-XRT candidate afterglow.
  63. GRB 081203A: optical observations
  64. Swift UVOT observations of GRB 081203A
  65. GRB 081203B: Naming correction for burst detected in Swift-BAT slew data
  66. GRB081203A: Swift/UVOT grism redshift
  67. GRB 081203A: Burst detection from Swift-BAT slew data
  68. GRB 081203A: Swift-BAT refined analysis
  69. GRB 081203: Enhanced Swift-XRT position
  70. GRB 081130B: MASTER prompt optical observations
  71. GRB081203: optical observation
  72. GRB 081203: Swift detection of a burst with a bright optical counterpart
  73. GRB 081128: optical observation
  74. GRB 081130B: Fermi GBM detection
  75. GRB 081130: Fermi GBM detection
  76. Swift Trigger 335971: Swift/UVOT Observations
  77. GRB 081126: afterglow photometry
  78. GRB 081126: Fermi GBM detection
  79. Fermi Gamma-ray Burst Monitor trigger 249166723 reclassification
  80. VLA Radio upper limit on GRB 081126
  81. GRB 081129: Fermi GBM detection
  82. GRB 081130: MASTER VWF prompt optical observations Fermi GRB
  83. GRB 081128A: optical observations
  84. Swift Trigger 335971 is probably not a real source
  85. Trigger 335971: Swift possible detection of a burst
  86. GRB081128: Swift/UVOT Upper Limits
  87. SGR 1806-20: Fermi GBM detection.
  88. GRB 081122B: Fermi GBM Detection
  89. GRB 081128: Swift-XRT refined analysis
  90. GRB 081128: Liverpool Telescope afterglow confirmation
  91. GRB081128: optical observations
  92. GRB081128 : Lulin optical follow-ups
  93. GRB 081128: Swift-BAT refined analysis
  94. GRB 081128: Enhanced Swift-XRT position
  95. GRB 081128: Optical observation of xinglong TNT
  96. GRB 081128: Swift detection of a burst
  97. GRB 081126: Swift observations continuing
  98. GRB081126: Afterglow photometry from Crni Vrh
  99. GRB 081126: GRT Optical Observation
  100. GRB 081127: Swift/UVOT Upper Limits

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov