Skip to main content
Retirement of GCN Classic VOEvent Brokers. 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. GRB 090823 Correction to BAT position
  2. GRB 090817: No host galaxy, no supernova
  3. Konus-Wind observations of GRB 090823
  4. GRB 090823 Long burst with IPN triangulation and BAT position
  5. GRB 090817: Swift/UVOT Observations of a Possible Late-Time Brightening
  6. GRB 090820: detection of a strong burst by RT-2 on board CORONAS PHOTON
  7. GRB 090820B: Fermi GBM detection
  8. GRB 090817: Swift/UVOT Observations of a Host Galaxy Candidate
  9. GRB 090820: MASTER-Net optical polarization observations
  10. GRB 090820: Fermi GBM Detection of a bright burst.
  11. GRB 090817: aphotometry of USNO-B1.0 341-0096763
  12. GRB 090817: Liverpool Telescope Observations
  13. GRB 090817: optical upper limit
  14. GRB 090817: Confirmation of the X-ray afterglow
  15. GRB 090815C: Swift refined analysis
  16. GRB 090817: Fermi GBM observation
  17. GRB 090817: Swift/UVOT Upper Limits
  18. GRB 090812: Konus-Wind and Swift/BAT joint spectral analysis
  19. GRB 090813: I-band observations from 1.5m OSN telescope
  20. GRB 090817: Swift-XRT observations
  21. GRB 090814A: optical observations
  22. GRB 090813: Suzaku WAM observation of the prompt emission
  23. GRB 090812: Suzaku WAM observation of the prompt emission
  24. GRB 090817: a long GRB localized by INTEGRAL
  25. VLA radio non-detection of GRB 090812
  26. GRB 090815B: Fermi GBM detection
  27. GRB 090815: Fermi GBM detection
  28. GRB 090813: CrAO optical obsevations
  29. GRB 090814B: Confirmation of the X-ray afterglow
  30. GRB090814A: NOT optical follow-ups
  31. GRB 090814B: I-band observations from 1.23m CAHA telescope
  32. GRB 090814B: Swift/UVOT Upper Limits
  33. GRB 090814B: Liverpool Telescope Observations
  34. Fermi Gamma-ray Burst Monitor trigger 271934815 is not a GRB
  35. GRB 090814C: Fermi GBM detection
  36. GRB 090814B: Swift-XRT detection of a possible afterglow.
  37. GRB 090814A: Swift/UVOT Observations
  38. GRB 090814A: Swift-XRT Team Refined Analysis
  39. GRB 090814A, RIMOTS optical upper limits
  40. GRB 090814A: Swift-BAT refined analysis
  41. GRB 090813: correction to GCN 9787
  42. GRB090814A: VLT spectroscopy
  43. GRB 090814: Enhanced Swift-XRT position
  44. GRB 090814B: a long GRB localized by INTEGRAL
  45. GRB 090814: GROND Detection of an Optical Afterglow Candidate
  46. GRB 090814: Swift detection of a burst
  47. GRB 090813: Fermi GBM observation
  48. Fermi Gamma-ray Burst Monitor trigger 271446248 is not a GRB
  49. GRB 090813: Swift-XRT refined analysis
  50. Fermi Gamma-ray Burst Monitor trigger 271833016 is not a GRB
  51. GRB 090813, Swift-BAT refined analysis
  52. Konus-Wind observations of GRB090813
  53. GRB090813: Swift/UVOT upper limits
  54. GRB 090813: Enhanced Swift-XRT position
  55. GRB 090813: Liverpool Telescope afterglow confirmation
  56. GRB 090813: P60 Optical Afterglow Confirmation
  57. GRB 090813: optical candidate from 1.23m CAHA telescope
  58. GRB 090813: Swift detection of a burst
  59. GRB 090812: WIRO NIR upper limit
  60. GRB 090812: Faulkes Telescope South Continued Optical Monitoring
  61. GRB 090812: RAPTOR detections during the burst
  62. GRB 090812: Swift XRT refined analysis
  63. GRB 090812, RIMOTS optical upper limits
  64. GRB 090812 Swift-BAT Refined Analysis
  65. GRB090812: Swift/UVOT observations
  66. GRB 090812: GROND Observations of the Optical/NIR Afterglow
  67. GRB 090812: Enhanced Swift-XRT position
  68. GRB 090812 VLT redshift
  69. GRB 090812: Liverpool Telescope afterglow confirmation
  70. GRB 090812: P60 Confirmation of Optical Afterglow
  71. GRB 090812: Swift detection of a burst with an optical counterpart
  72. GRB 090807B: Fermi GBM detection
  73. GRB 090809: Further NOT optical observations
  74. VLA radio upper limit on GRB 090809
  75. GRB 090621B: MAGIC telescope GeV observation
  76. GRB 090621A: MAGIC telescope GeV observation
  77. GRB 090809: WHT observations
  78. GRB 090809 X-shooter redshift
  79. GRB 090809B: Fermi GBM detection
  80. GRB 090809: Swift-XRT refined analysis
  81. GRB090809: Swift/UVOT observations
  82. GRB 090809: Enhanced Swift-XRT position
  83. GRB 090809: Swift-BAT refined analysis
  84. GRB 090809: afterglow confirmation at the NOT
  85. GRB 090809: Swift detection of a burst with a possible optical counterpart
  86. GRB 090807: Liverpool Telescope observations
  87. GRB 090807: MITSuME optical upper limit
  88. GRB 090807: Swift/UVOT Upper Limits
  89. GRB 090807: Swift-XRT refined analysis
  90. GRB 090807, Swift-BAT refined analysis
  91. GRB 090807: Enhanced Swift-XRT position
  92. GRB 090807, RIMOTS optical upper limits
  93. GRB 090807: Swift detection of a burst
  94. Fermi Gamma-ray Burst Monitor trigger 271275771 is not a GRB
  95. GRB 090802B: Fermi GBM detection
  96. IPN Triangulation and Konus-Wind observaions of GRB090727B
  97. GRB 090802: Fermi GBM detection
  98. GRB 090726: optical observation
  99. Swift-BAT trigger 358760 is most likely not a GRB
  100. Swift trigger 358760 is probably a noise event

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