Skip to main content
Passing of Scott Barthelmy, GCN Founder 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 090407: Swift-BAT refined analysis
  2. Konus-Wind and Konus-RF observations of GRB 090406
  3. GRB 090407: ROTSE-III Optical Limits
  4. GRB 090407: Swift detection of a burst
  5. GRB 090404: millimeter detection
  6. GRB 090404: nIR observations at Calar Alto
  7. GRB 090405: Fermi GBM Detection
  8. GRB 090403: Fermi GBM detection
  9. GRB 090404: GROND upper limits
  10. GRB 090404: further NOT observations
  11. Swift/UVOT observations of GRB090404
  12. GRB 090404: NOT observations
  13. GRB 090404: optical observations at BOOTES-3 and 1.5-m OSN
  14. GRB 090404: Swift-XRT Team refined analysis
  15. GRB 090404: Xinglong TNT optical Upper Limit
  16. GRB 090404: Swift-BAT refined analysis
  17. GRB 090404: Enhanced Swift-XRT position
  18. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  19. GRB 090404: Swift detection of a burst
  20. GRB 090401A: Suzaku WAM observation of the prompt emission
  21. GRB 090401B: Suzaku WAM observation of the prompt emission
  22. Konus-Wind observation of GRB 090401B
  23. GRB 090401B: Xinglong TNT optical Upper Limit
  24. GRB 090401B: VLA radio upper limit
  25. GRB 090401B: Upper limits of MITSuME optical observation
  26. GRB090401B, RIMOTS optical upper limits
  27. GRB 090401B: NOT optical observations
  28. GRB 090328: Fermi-LAT refined analysis
  29. Swift/UVOT observations of GRB090401B
  30. GRB 090401B: AGILE refined analysis
  31. Swift/UVOT observations of GRB090401B
  32. GRB 090401B: Swift XRT Refined Analysis
  33. GRB 090331: Fermi GBM detection
  34. Konus-Wind observation of GRB 090401A
  35. GRB 090401B: Enhanced Swift-XRT position
  36. AGILE Gamma-ray detection of GRB 090401B
  37. GRB 090401B: Swift-BAT refined analysis
  38. Swift/UVOT detection of GRB090401B
  39. GRB 090401B: Swift detection of a burst
  40. GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
  41. GRB 090401, Swift-BAT refined analysis
  42. GRB 090323: Further TLS detections - a break?
  43. GRB 090401: Swift detection of a burst
  44. GRB 090324: Suzaku WAM observation of the prompt emission
  45. GRB 090328: Radio afterglow detection
  46. GRB 090326: Fermi GBM detection
  47. GRB 090328: BOOTES-3 optical observations
  48. GRB 090328: Fermi GBM Spectral Analysis
  49. GRB 090328B: Fermi GBM Detection
  50. GRB 090330: Fermi GBM detection
  51. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  52. GRB 090328: Gemini South Redshift
  53. GRB 090328: Swift XRT refined analysis
  54. GRB090323: Optical observations from NOT
  55. Konus-Wind observation of GRB 090328
  56. GRB 090328: IPN Triangulation
  57. GRB 090328: Swift UVOT observations
  58. GRB 090323: WSRT Radio Detection
  59. GRB 090328: Updated position/optical afterglow candidate
  60. GRB 090328: Possible Swift/XRT detection
  61. Fermi LAT and GBM detections of GRB090328
  62. GRB 090323: Radio afterglow detection
  63. GRB 090323: Additional Lick observations
  64. GRB 090323: TLS detection at 5 days, no break
  65. GRB 090327: Fermi GBM detection
  66. GRB 090323: Faulkes Telescope South Observations
  67. GRB 090320B: MASTER-Net prompt optical observations
  68. GRB 090323: RTT150 optical observations
  69. GRB 090323: Lick observations
  70. GRB 090323: Fermi GBM Spectral Analysis
  71. GRB 090323: Optical observation of xinglong TNT
  72. GRB 090323 TLS detection - still bright
  73. GRB 090323: UVOT Detection of Afterglow
  74. GRB 090323: Swift-XRT refined analysis
  75. Konus-Wind observation of GRB 090323
  76. GRB 090324: SuperAGILE Localization of a Long GRB
  77. GRB 090323 Gemini-South Redshift
  78. GRB 090323: P60 Afterglow Confirmation
  79. GRB 090323: GROND Detection of the Afterglow and Photo-z
  80. SGR J1550-5418: two Fermi GBM triggers on March 22
  81. GRB 090323: Possible XRT Counterpart
  82. IPN triangulation of GRB090323
  83. GRB 090320C: Fermi GBM Detection
  84. Fermi GBM and LAT detections of GRB 090323
  85. GRB 090320B: Fermi GBM detection.
  86. GRB 090319: Fermi GBM detection
  87. GRB 090320A: Fermi GBM detection
  88. Further 15GHz observations of GRB090313
  89. GRB 090313: WSRT Radio Detection
  90. X-shooter observations of GRB 090313
  91. A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418
  92. GRB 090315: Suzaku WAM observation of the prompt emission
  93. GRB 090313: VLT spectroscopy
  94. GRB090313: radio detection with the VLA
  95. Konus-Wind observation of GRB 090315
  96. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  97. GRB 090313, SMARTS optical/IR observations
  98. Further radio observation of GRB 090313
  99. Further Swift/UVOT observations of GRB 090313
  100. GRB 090313: detection with CARMA in 3mm band

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