Skip to main content
New JavaScript client! 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 090330: Fermi GBM detection
  2. GRB 090328: GROND Detection of the Optical/NIR Afterglow
  3. GRB 090328: Gemini South Redshift
  4. GRB 090328: Swift XRT refined analysis
  5. GRB090323: Optical observations from NOT
  6. Konus-Wind observation of GRB 090328
  7. GRB 090328: IPN Triangulation
  8. GRB 090328: Swift UVOT observations
  9. GRB 090323: WSRT Radio Detection
  10. GRB 090328: Updated position/optical afterglow candidate
  11. GRB 090328: Possible Swift/XRT detection
  12. Fermi LAT and GBM detections of GRB090328
  13. GRB 090323: Radio afterglow detection
  14. GRB 090323: Additional Lick observations
  15. GRB 090323: TLS detection at 5 days, no break
  16. GRB 090327: Fermi GBM detection
  17. GRB 090323: Faulkes Telescope South Observations
  18. GRB 090320B: MASTER-Net prompt optical observations
  19. GRB 090323: RTT150 optical observations
  20. GRB 090323: Lick observations
  21. GRB 090323: Fermi GBM Spectral Analysis
  22. GRB 090323: Optical observation of xinglong TNT
  23. GRB 090323 TLS detection - still bright
  24. GRB 090323: UVOT Detection of Afterglow
  25. GRB 090323: Swift-XRT refined analysis
  26. Konus-Wind observation of GRB 090323
  27. GRB 090324: SuperAGILE Localization of a Long GRB
  28. GRB 090323 Gemini-South Redshift
  29. GRB 090323: P60 Afterglow Confirmation
  30. GRB 090323: GROND Detection of the Afterglow and Photo-z
  31. SGR J1550-5418: two Fermi GBM triggers on March 22
  32. GRB 090323: Possible XRT Counterpart
  33. IPN triangulation of GRB090323
  34. GRB 090320C: Fermi GBM Detection
  35. Fermi GBM and LAT detections of GRB 090323
  36. GRB 090320B: Fermi GBM detection.
  37. GRB 090319: Fermi GBM detection
  38. GRB 090320A: Fermi GBM detection
  39. Further 15GHz observations of GRB090313
  40. GRB 090313: WSRT Radio Detection
  41. X-shooter observations of GRB 090313
  42. A bright burst from AXP 1E 1547.0-5408/SGR J1550-5418
  43. GRB 090315: Suzaku WAM observation of the prompt emission
  44. GRB 090313: VLT spectroscopy
  45. GRB090313: radio detection with the VLA
  46. Konus-Wind observation of GRB 090315
  47. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  48. GRB 090313, SMARTS optical/IR observations
  49. Further radio observation of GRB 090313
  50. Further Swift/UVOT observations of GRB 090313
  51. GRB 090313: detection with CARMA in 3mm band
  52. GRB090305B: MASTER-net prompt optical short burst observations
  53. Radio detection of GRB090313
  54. GRB 090313: MITSuME Okayama observation
  55. GRB 090313: Additional Gemini-S photometry
  56. GRB 090313: WSRT Radio Observations
  57. GRB 090313: Light curve steepening
  58. GRB 090313: TAROT La Silla observatory optical detection
  59. GRB 090313: Gemini-S photometry
  60. GRB 090313: Zadko Telescope observations
  61. GRB 090313 - PAIRITEL NIR detections
  62. GRB 090313: Gemini-S redshift
  63. GRB 090313 optical observations
  64. GRB 090313: Ongoing plateau phase
  65. GRB 090313: Swift-XRT refined analysis
  66. GRB 090313: Swift/UVOT upper limits
  67. GRB 090313: Faulkes Telescope North observations
  68. GRB 090313: Sustained optical brightness (correction)
  69. GRB 090306B: Confirmation of the X-ray afterglow
  70. GRB 090313: Swift-BAT refined analysis
  71. GRB 090313: Sustained optical brightness
  72. GRB 090313: SDSS object underlying the optical afterglow position
  73. GRB 090313, GROND observations
  74. GRB 090309, Swift-BAT lag analysis
  75. GRB 090313: Swift detection of a burst
  76. GRB 090313: Swift detection of a burst
  77. GRB 090313 OA candidate
  78. Swift trigger 346250 is probably not a burst
  79. GRB090310: Fermi GBM detection
  80. GRB 090205: Zadko Telescope late-time observations
  81. GRB 090309A: GROND upper limits
  82. GRB 090307A: TAROT Calern observatory optical observations
  83. GRB 090309: Swift/UVOT Upper Limits
  84. GRB090305B: Fermi GBM detection
  85. GRB 090309B: Fermi GBM detection
  86. GRB 090309: Swift-XRT refined analysis
  87. GRB 090309: Enhanced Swift-XRT position
  88. GRB 090306B: INTEGRAL SPI-ACS light curve
  89. GRB 090309, Swift-BAT refined analysis
  90. GRB 090308: GROND observations
  91. GRB 090308: Gemini GMOS Observations
  92. GRB 090309: Swift detection of a burst
  93. GRB 090308B: Fermi GBM detection
  94. GRB 090308: Swift/UVOT Upper Limits
  95. GRB 090307B: Fermi GBM detection
  96. GRB 090306C: Fermi GBM detection
  97. GRB 090307: GROND Upper Limits
  98. GRB 090306B: GROND Upper Limits
  99. GRB 090305C: Suzaku WAM observation of the prompt emission
  100. GRB 090308: Swift-XRT refined analysis

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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