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 091221: Swift-XRT refined analysis
  2. GRB 091221: Enhanced Swift-XRT position
  3. GRB 091221, GROND observations
  4. GRB 091221: UVOT Confirmation of an Optical Afterglow
  5. GRB 091221: ROTSE-III Detection of Optical Counterpart
  6. GRB 091221: Swift detection of a burst
  7. Swift trigger 379449 (possible GRB) is not a burst
  8. GRB 091215: Faulkes Telescope North observations
  9. Trigger 379449: Swift detection of a possible burst
  10. GRB 091208B: Xinglong TNT optical observation
  11. GRB 091208A: Suzaku WAM observation of the prompt emission
  12. GRB 091208A: GAO 150cm telescope Optical Observation
  13. Konus-Wind observation of GRB 091208A
  14. GRB 091208B: GAO 150cm telescope Optical Observation
  15. GRB091208A: Swift/UVOT refined analysis
  16. GRB 091208B: optical observations
  17. GRB 091208B: Keck HIRES redshift confirmation
  18. GRB 091208B: GROND observations
  19. GRB 091208A: Swift-XRT observations
  20. GRB091208B: NOT optical observations
  21. GRB 091208B: Swift-XRT refined analysis
  22. GRB091208B: Swift/UVOT refined analysis
  23. GRB 091208B: Fermi GBM observation
  24. GRB 091208B, Swift-BAT refined analysis
  25. GRB 091208A Swift-BAT refined analysis
  26. GRB 091208B: Gemini-North redshift
  27. GRB 091208B: Faulkes Telescope North and South Optical Afterglow
  28. GRB 091208A, RIMOTS optical upper limits
  29. GRB 091208B: MITSuME Akeno Optical Observation
  30. GRB 091208B: Enhanced Swift-XRT position
  31. GRB 091208B: MITSuME Okayama Optical Observation
  32. GRB 091208B, RIMOTS optical upper limits
  33. GRB 091208B: Swift detection of a burst with an optical afterglow
  34. GRB 091208B: BOOTES-3 optical afterglow
  35. GRB 091208: ROTSE-III Optical Limits
  36. GRB 091208: Swift detection of a burst
  37. Short X-ray Transient, RIMOTS optical upper limits
  38. A small revision to the GRB-naming convention
  39. GRB 091123: Suzaku WAM observation of the prompt emission
  40. GRB 091127: Skynet/PROMPT Observations of Possible Host Galaxy
  41. GRB 091127: GAO 150cm telescope Optical Observation
  42. GRB 091202: GTC & CAHA optical/nIR afterglow candidate
  43. GRB 091109A: GROND confirmation of redshift z = 3.5
  44. GRB091127: Continuing Swift/UVOT Observations
  45. GRB 091127, SMARTS optical/IR afterglow observations
  46. GRB091202: Swift-XRT refined analysis
  47. GRB 091202: Swift/UVOT Upper Limits
  48. GRB 091202: Liverpool Telescope observations
  49. GRB 091202: Optical and NIR observations
  50. GRB 091202 - UVOT-enhanced XRT position
  51. GRB 091127: Zadko Telescope Observations
  52. GRB 091126A: Suzaku WAM observation of the prompt emission
  53. GRB 091202: TAROT Calern observatory optical observations
  54. GRB 091202: Liverpool Telescope Observations
  55. GRB 091202: a long GRB detected by INTEGRAL
  56. GRB 091127: redshift confirmation with X-shooter
  57. GRB 091117: Chandra Observations
  58. GRB 091020: MASTER-Net optical polarization observations
  59. GRB 091127: Skynet/PROMPT Continued Observations of Fading
  60. Short X-ray Transient Detection by MAXI/GSC
  61. Konus-Wind observation of very long GRB 091123
  62. GRB 091130A: Xinglong TNT upper limit
  63. GRB 091123: Fermi GBM detection of a very long burst
  64. GRB 091126B: Fermi GBM detection
  65. GRB 091127: Suzaku WAM observation of the prompt emission
  66. GRB 091126: Fermi GBM detection
  67. GRB 091130B: Swift-XRT team refined analysis
  68. GRB 091130B: Swift-BAT refined analysis
  69. GRB 091130B: Swift/UVOT Upper Limits
  70. GRB 091127: Skynet/PROMPT Observations of Fading
  71. GRB 091130B: Enhanced Swift-XRT position
  72. Swift trigger 377436 (possible GRB 091130A) is not a burst
  73. GRB 091130B: MASTER observations
  74. GRB 091130B: SDSS galaxy at XRT location
  75. GRB 091130B: Swift detection of a burst
  76. GRB 091130: MASTER observations
  77. GRB 091130: Swift detection of a possible burst
  78. GRB 091127: Radio observations
  79. GRB 091128: Fermi GBM detection
  80. Konus-Wind observation of GRB 091127
  81. GRB 091127: TAROT La Silla observatory optical observations
  82. GRB 091127: optical observations
  83. GRB 091127: LABOCA/APEX submm observations
  84. GRB 091127: Further NOT optical observations
  85. GRB 091127: Fermi GBM detection
  86. GRB 091127: MASTER early optical transient polarimetry
  87. GRB 091127: Gemini-N redshift
  88. GRB 091127: Swift-XRT afterglow detection and analysis
  89. GRB 091127: TAROT La Silla observatory optical decay
  90. GRB 091127: Swift/UVOT observations
  91. GRB 091127: CAHA 1.23m I-band observations
  92. GRB 091127: Swift-BAT refined analysis
  93. GRB 091127: NOT observations
  94. GRB 091127 : GROND observations
  95. GRB 091127: REM NIR afterglow detection
  96. GRB 091127: Swift/UVOT Detection of an Optical Afterglow
  97. GRB 091127: Liverpool Telescope afterglow candidate
  98. GRB 091127: Swift detection of a burst
  99. IPN Triangulation of GRB091120
  100. Konus-Wind observation of GRB 091120

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