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 090313: Swift-XRT refined analysis
  2. GRB 090313: Swift/UVOT upper limits
  3. GRB 090313: Faulkes Telescope North observations
  4. GRB 090313: Sustained optical brightness (correction)
  5. GRB 090306B: Confirmation of the X-ray afterglow
  6. GRB 090313: Swift-BAT refined analysis
  7. GRB 090313: Sustained optical brightness
  8. GRB 090313: SDSS object underlying the optical afterglow position
  9. GRB 090313, GROND observations
  10. GRB 090309, Swift-BAT lag analysis
  11. GRB 090313: Swift detection of a burst
  12. GRB 090313: Swift detection of a burst
  13. GRB 090313 OA candidate
  14. Swift trigger 346250 is probably not a burst
  15. GRB090310: Fermi GBM detection
  16. GRB 090205: Zadko Telescope late-time observations
  17. GRB 090309A: GROND upper limits
  18. GRB 090307A: TAROT Calern observatory optical observations
  19. GRB 090309: Swift/UVOT Upper Limits
  20. GRB090305B: Fermi GBM detection
  21. GRB 090309B: Fermi GBM detection
  22. GRB 090309: Swift-XRT refined analysis
  23. GRB 090309: Enhanced Swift-XRT position
  24. GRB 090306B: INTEGRAL SPI-ACS light curve
  25. GRB 090309, Swift-BAT refined analysis
  26. GRB 090308: GROND observations
  27. GRB 090308: Gemini GMOS Observations
  28. GRB 090309: Swift detection of a burst
  29. GRB 090308B: Fermi GBM detection
  30. GRB 090308: Swift/UVOT Upper Limits
  31. GRB 090307B: Fermi GBM detection
  32. GRB 090306C: Fermi GBM detection
  33. GRB 090307: GROND Upper Limits
  34. GRB 090306B: GROND Upper Limits
  35. GRB 090305C: Suzaku WAM observation of the prompt emission
  36. GRB 090308: Swift-XRT refined analysis
  37. Radio observation of GRB 090201 with ATCA
  38. Radio observation of GRB 090117 with ATCA
  39. Radio observation of GRB 081226b with ATCA
  40. Radio observation of GRB 081226a with ATCA
  41. Radio observation of GRB 081007 with ATCA
  42. ATCA observation of SGR J1550-5418
  43. GRB 090308: Swift-BAT refined analysis
  44. GRB 090308: Swift detection of a burst
  45. GRB 090306B: Possible XRT afterglow
  46. GRB 090307: Swift-XRT afterglow confirmation and analysis
  47. GRB 090307: Swift-BAT refined analysis of trigger 345551
  48. GRB 090306B: Burst detection from Swift-BAT slew data
  49. Swift Trigger 345551 is probably not a GRB
  50. Swift-BAT trigger 345396 is not a GRB
  51. IPN localization of short GRB 090305C
  52. Fermi GBM trigger 090305784 is not a GRB
  53. GRB 090306: Swift detection of a possible burst
  54. GRB 090305: Swift/UVOT Upper Limits
  55. GRB 090305: Swift-XRT refined analysis
  56. GRB 090305, Swift-BAT refined analysis
  57. GRB 090227A: Suzaku WAM observation of the prompt emission
  58. GRB 090305: Magellan confirmation of the optical afterglow
  59. GRB090305: GMOS-S Candidate Optical Afterglow
  60. GRB 090305: Swift detection of a short burst
  61. GRB 090303: Fermi GBM detection
  62. GRB 090304: Fermi GBM detection
  63. GRB 090301A: Suzaku WAM observation of the prompt emission
  64. Konus-RF catches first GRB and SGR bursts
  65. GRB 090228B: Fermi GBM detection
  66. Konus-Wind observation of bright short GRB 090227B
  67. IPN localization of short bright GRB 090227B
  68. Konus-Wind observation of GRB 090301A
  69. GRB 090301A: Swift-BAT refined analysis
  70. GRB 090301B: Fermi GBM detection
  71. GRB 090227B: Fermi GBM detection
  72. GRB 090301: Swift detection of a burst
  73. Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
  74. GRB 090228: Fermi GBM detection
  75. GRB 090227: Fermi GBM detection
  76. GRB 090206: Fermi GBM detection
  77. SGR J1550-5418
  78. GRB 081211B: Nearby cluster
  79. Ongoing activity of AXP/SGR 1E1547.0-5408
  80. GRB 090222: Fermi GBM detection
  81. GRB 090219: Fermi GBM detection
  82. Swift Restored
  83. Swift Trigger 343319 is not a GRB
  84. GRB 090217: Suzaku WAM observation of the prompt emission
  85. GRB090217: XRT analysis
  86. Konus-Wind observation of GRB 090217
  87. IPN localization of GRB 090217
  88. GRB 090213: Fermi GBM detection
  89. GRB090217: Fermi-LAT Detection
  90. GRB 090217: Fermi GBM detection
  91. SGR activity seen by BAT during ICSP Ionospheric Events
  92. Detailed lightcurves of ICSP VLF Observation of SGR/AXP 1E1547.0-5408
  93. GRB 090207 - Fermi GBM Observations
  94. Fermi Gamma-ray Burst Monitor trigger 255729682 is not a GRB
  95. GRB 090129: Fermi GBM detection
  96. VLA radio upper limit on GRB 090205
  97. GRB 090205: VLT optical decay
  98. Fermi Gamma-ray Burst Monitor trigger 255541748 cannot be classified
  99. GRB 090205: Swift/UVOT Upper Limits
  100. GRB 090205: VLT refined redshift

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