Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

37503 results found.

  1. GRB 090108: Fermi GBM Detection
  2. GRB 090111: Swift-XRT refined analysis
  3. GRB 090111: Enhanced Swift-XRT position
  4. GRB 090111: Swift detection of a burst
  5. GRB 090107B: Suzaku WAM observation of the prompt emission
  6. GRB090107B: Fermi GBM Detection
  7. GRB 090102: WSRT Radio Observations
  8. GRB 090107B: Swift XRT afterglow confirmation
  9. GRB 090107B: Swift/UVOT Observations
  10. GRB 090107B: Swift-XRT detection of possible afterglow
  11. GRB 090107B optical observations
  12. GRB 090107B: ROTSE-III Optical Limits
  13. GRB 090107B: a long GRB localized by INTEGRAL
  14. Fermi/GBM detection of GRB 081226A
  15. Fermi/GBM detection of GRB 081225
  16. GRB 090107: Swift-BAT refined analysis
  17. GRB 090107: Swift detection of a burst
  18. GRB 081231: Fermi GBM Detection
  19. GRB 090102: optical decay
  20. VLA radio upper limit on GRB 090102
  21. GRB 090102: GRT Optical Observation
  22. Konus-Wind observation of GRB 090102
  23. GRB 081229: Fermi GBM detection
  24. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  25. GRB 090102: P60 Imaging and P200 Spectroscopy
  26. GRB 090102 Observations from IAC80
  27. GRB 090102: GROND observations of the optical afterglow
  28. Swift UVOT observations of GRB 090102
  29. GRB 090102: Swift-BAT refined analysis
  30. GRB 090102: Swift burst of interest
  31. GRB 090102: Swift XRT refined analysis
  32. GRB 090102: NOT redshift
  33. GRB 090102: Enhanced Swift-XRT position
  34. GRB 090102: TAROT Calern observatory optical light curve
  35. GRB 090102: REM observations of a bright afterglow
  36. GRB 090102: Swift detection of a burst with an optical counterpart
  37. GRB 090102: TAROT Calern observatory optical observations
  38. GRB 081230: GROND confirmation of the afterglow
  39. GRB 081230, Swift-BAT refined analysis
  40. GRB081230: Swift-XRT refined analysis
  41. GRB 081230 Swift/UVOT Observations
  42. GRB 081230: Enhanced Swift-XRT position
  43. GRB 081230: Swift/UVOT Detection of an Optical Afterglow
  44. GRB 081230: ROTSE-III Detection of Optical Counterpart
  45. GRB 081230: Swift detection of a burst
  46. GRB 081228: GROND confirmation of the optical/NIR afterglow
  47. GRB 081226B: Fermi GBM observation
  48. GRB 081226C: Fermi GBM detection
  49. GRB 081228, Swift-BAT refined analysis
  50. VLA radio detection of GRB 081221
  51. GRB 081228: Swift/UVOT Upper Limits
  52. GRB 081228: Swift-XRT Team refined analysis
  53. GRB 081228: detection by GROND
  54. GRB 081228: Enhanced Swift-XRT position
  55. GRB 081228: TAROT Calern observatory optical observations
  56. GRB 081228: Swift detection of a burst
  57. VLA radio observation of GRB 081221
  58. GRB 081226B: Swift XRT and UVOT upper limits
  59. GRB 081224: Suzaku WAM observation of the prompt emission
  60. GRB 081226: Swift-XRT refined analysis
  61. GRB 081226A: Swift UVOT Upper Limits
  62. GRB 081226: Second epoch of Gemini-South imaging
  63. GRB 081226A: Swift-BAT refined analysis
  64. GRB 081226B: a short-hard GRB detected by INTEGRAL
  65. GRB 081226: Gemini-South spectrum of possible afterglow
  66. GRB 081226: Gemini-South imaging
  67. GRB 081226: GROND afterglow candidate
  68. GRB 081226: ROTSE-III Optical Limits
  69. GRB 081226: Swift detection of a possible short-hard burst
  70. GRB 080810: optical observations
  71. GRB 081211B: optical observations
  72. GRB081224: LAT retraction
  73. GRB 081224: Swift-XRT observation
  74. GRB 081222: MITSuME optical observation
  75. GRB 081224: Fermi GBM Detection & LAT Localization
  76. GRB 080810: optical observations
  77. Konus-Wind observation of GRB 081222
  78. GRB 081223: Fermi GBM detection
  79. GRB 081221: GROND observations
  80. GRB 081222: Gemini-N confirmation of redshift z=2.77
  81. GRB 081222:Optical afterglow observation
  82. VLA radio upper limit on GRB 081222
  83. GRB 081222: Fermi GBM observation
  84. Fermi Gamma-ray Burst Monitor trigger 251687595 reclassification
  85. GRB 081222: Gemini-South absorption redshift
  86. GRB 081221: Probable host galaxy in Keck imaging
  87. GRB 081204C: Fermi GBM detection
  88. GRB 081222, Swift-BAT refined analysis
  89. GRB 081221, Swift-BAT refined analysis
  90. GRB081222 optical limit by "Pi of the Sky"
  91. Konus-Wind observation of very bright GRB 081215A
  92. GRB 081222: Swift XRT refined analysis
  93. GRB081221: Fermi GBM observation
  94. Swift/UVOT observations of GRB 081221
  95. IPN triangulation of bright GRB 081215A
  96. GRB 081221: Swift-XRT Refined Analysis
  97. GRB 081221: pseudo-redshift (pz=0.7) from the spectral parameters of the prompt emission
  98. GRB 081222: Faulkes Telescope South observations
  99. GRB 081221: Gemini-N nIR imaging
  100. GRB081203A: BTA observation

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