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 090107B: Swift-XRT detection of possible afterglow
  2. GRB 090107B optical observations
  3. GRB 090107B: ROTSE-III Optical Limits
  4. GRB 090107B: a long GRB localized by INTEGRAL
  5. Fermi/GBM detection of GRB 081226A
  6. Fermi/GBM detection of GRB 081225
  7. GRB 090107: Swift-BAT refined analysis
  8. GRB 090107: Swift detection of a burst
  9. GRB 081231: Fermi GBM Detection
  10. GRB 090102: optical decay
  11. VLA radio upper limit on GRB 090102
  12. GRB 090102: GRT Optical Observation
  13. Swift triggered on the HMXB 1A 1118-61
  14. Konus-Wind observation of GRB 090102
  15. GRB 081229: Fermi GBM detection
  16. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  17. GRB 090102: P60 Imaging and P200 Spectroscopy
  18. GRB 090102 Observations from IAC80
  19. GRB 090102: GROND observations of the optical afterglow
  20. Swift UVOT observations of GRB 090102
  21. GRB 090102: Swift-BAT refined analysis
  22. GRB 090102: Swift burst of interest
  23. GRB 090102: Swift XRT refined analysis
  24. GRB 090102: NOT redshift
  25. GRB 090102: Enhanced Swift-XRT position
  26. GRB 090102: TAROT Calern observatory optical light curve
  27. GRB 090102: REM observations of a bright afterglow
  28. GRB 090102: Swift detection of a burst with an optical counterpart
  29. GRB 090102: TAROT Calern observatory optical observations
  30. GRB 081230: GROND confirmation of the afterglow
  31. GRB 081230, Swift-BAT refined analysis
  32. GRB081230: Swift-XRT refined analysis
  33. GRB 081230 Swift/UVOT Observations
  34. GRB 081230: Enhanced Swift-XRT position
  35. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  36. GRB 081230: ROTSE-III Detection of Optical Counterpart
  37. GRB 081230: Swift detection of a burst
  38. GRB 081228: GROND confirmation of the optical/NIR afterglow
  39. GRB 081226B: Fermi GBM observation
  40. GRB 081226C: Fermi GBM detection
  41. GRB 081228, Swift-BAT refined analysis
  42. VLA radio detection of GRB 081221
  43. GRB 081228: Swift/UVOT Upper Limits
  44. GRB 081228: Swift-XRT Team refined analysis
  45. GRB 081228: detection by GROND
  46. GRB 081228: Enhanced Swift-XRT position
  47. GRB 081228: TAROT Calern observatory optical observations
  48. GRB 081228: Swift detection of a burst
  49. VLA radio observation of GRB 081221
  50. GRB 081226B: Swift XRT and UVOT upper limits
  51. GRB 081224: Suzaku WAM observation of the prompt emission
  52. GRB 081226: Swift-XRT refined analysis
  53. GRB 081226A: Swift UVOT Upper Limits
  54. GRB 081226: Second epoch of Gemini-South imaging
  55. GRB 081226A: Swift-BAT refined analysis
  56. GRB 081226B: a short-hard GRB detected by INTEGRAL
  57. GRB 081226: Gemini-South spectrum of possible afterglow
  58. GRB 081226: Gemini-South imaging
  59. GRB 081226: GROND afterglow candidate
  60. GRB 081226: ROTSE-III Optical Limits
  61. GRB 081226: Swift detection of a possible short-hard burst
  62. GRB 080810: optical observations
  63. GRB 081211B: optical observations
  64. GRB081224: LAT retraction
  65. GRB 081224: Swift-XRT observation
  66. GRB 081222: MITSuME optical observation
  67. GRB 081224: Fermi GBM Detection & LAT Localization
  68. GRB 080810: optical observations
  69. Konus-Wind observation of GRB 081222
  70. GRB 081223: Fermi GBM detection
  71. GRB 081221: GROND observations
  72. GRB 081222: Gemini-N confirmation of redshift z=2.77
  73. GRB 081222:Optical afterglow observation
  74. VLA radio upper limit on GRB 081222
  75. GRB 081222: Fermi GBM observation
  76. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  77. GRB 081222: Gemini-South absorption redshift
  78. GRB081222: Swift/UVOT further observations
  79. GRB 081221: Probable host galaxy in Keck imaging
  80. GRB 081204C: Fermi GBM detection
  81. GRB 081222, Swift-BAT refined analysis
  82. GRB 081221, Swift-BAT refined analysis
  83. GRB081222 optical limit by "Pi of the Sky"
  84. Konus-Wind observation of very bright GRB 081215A
  85. GRB 081222: Swift XRT refined analysis
  86. GRB081221: Fermi GBM observation
  87. Swift/UVOT observations of GRB 081221
  88. IPN triangulation of bright GRB 081215A
  89. GRB 081221: Swift-XRT Refined Analysis
  90. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  91. GRB 081222: Faulkes Telescope South observations
  92. GRB 081221: Gemini-N nIR imaging
  93. GRB081222, optical observation
  94. GRB081222: Swift/UVOT detection of an optical afterglow
  95. GRB081203A: BTA observation
  96. Konus-Wind observation of GRB 081221
  97. GRB 081222: GROND Detection of the Optical/NIR Afterglow
  98. GRB081222: REM candidate afterglow
  99. GRB 081222: Swift detection of a burst with a bright optical afterglow
  100. GRB 081221: Enhanced Swift-XRT position

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