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"

35958 results found.

  1. GRB 220506A: Swift-XRT afterglow detection
  2. GRB 220506A: Tiled Swift observations
  3. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  4. GRB 220430A: Nanshan/NEXT optical upper limit
  5. GRB 220430A: Nanshan/HMT optical upper limit
  6. GRB 220430A: GIT optical upper limits
  7. IPN triangulation of GRB 220423A
  8. GRB 220427A: LCO Optical Observations
  9. GRB 220501A: Swift-BAT refined analysis
  10. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  11. GRB 220501A: BOOTES-1 optical upper limit
  12. GRB 220501A: Fermi GBM observation
  13. GRB 220430A: AstroSat CZTI detection
  14. GRB 220501A: GRANDMA/TJML Optical Observations
  15. GRB 220501A: Fermi GBM Final Real-time Localization
  16. GRB 220501A: Swift detection of a burst
  17. GRB 220430A: Swift-BAT refined analysis
  18. GRB 220430A: CAHA 2.2m telescope optical limit
  19. GRB 220430A: Swift-XRT refined Analysis
  20. Swift GRB 220430A: Global MASTER-Net observations report
  21. GRB 220430A: GRANDMA observations
  22. GRB 220430A: Mondy and AbAO optical upper limits
  23. GRB 220430A: AGILE detection
  24. GRB 220430A: MeerLICHT optical upper limits
  25. GRB 220430A: Enhanced Swift-XRT position
  26. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
  27. GRB 220427A: Swift-BAT refined analysis
  28. GRB 220427A: VLT/X-shooter photometry
  29. GRB 220426A: Swift-XRT and UVOT observations
  30. GRB 220423A: Detection by VZLUSAT-2
  31. Konus-Wind detection of GRB 220427A
  32. GRB 220427A: Swift-XRT refined Analysis
  33. GRB 220427A: Enhanced Swift-XRT position
  34. GRB 220426A: Tiled Swift observations
  35. GRB 220427A: Swift detection of a burst with an optical counterpart
  36. Konus-Wind detection of GRB 220426A
  37. IPN triangulation of GRB 220426A
  38. GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
  39. Fermi GRB 220426A: Global MASTER-Net observations report
  40. GRB 220426A: Fermi GBM detection
  41. GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
  42. Fermi GRB 220426B: Global MASTER-Net observations report
  43. GRB 220426B: Fermi GBM Final Real-time Localization
  44. GRB 220426A: BALROG localization (Fermi Trigger 672648596/ GRB 220426285)
  45. Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
  46. GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
  47. On the AGILE detection of GRB 220423A
  48. GRB 220423A: AGILE detection
  49. GRB 220421B: Detection by VZLUSAT-2
  50. GRB 220421A: Fermi GBM observation
  51. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  52. Fermi GBM trigger 672128054/220420260 is not a GRB
  53. GRB 220418B: Swift-XRT observations
  54. GRB 220418B Fermi GBM observation
  55. “GRB 220420A” is not a GRB
  56. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  57. GRB 220403C: Further Swift-XRT observations
  58. GRB 220418B: Swift ToO observations
  59. GRB 220417A: Fermi GBM detection
  60. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  61. IPN triangulation of GRB 220411A
  62. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  63. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  64. GRB 220412B: Swift/UVOT Upper Limits
  65. Fermi GRB 220418A: Global MASTER-Net observations report
  66. GRB 220418B: Fermi GBM Final Real-time Localization
  67. GRB 220418A: Fermi GBM Final Real-time Localization
  68. Fermi GRB 220417A: Global MASTER-Net observations report
  69. GRB 220417A: Fermi GBM Final Real-time Localization
  70. GRB 220412B: Swift-BAT refined analysis
  71. Konus-Wind detection of GRB 220412B
  72. GRB 220412B: Fermi GBM observation
  73. Konus-Wind detection of GRB 220403C
  74. GRB 220408B: Fermi GBM observation
  75. Konus-Wind detection of GRB 220408B
  76. GRB 220412B: TNG optical observations
  77. GRB 220412A: GRANDMA observations
  78. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  79. GRB 220412A: BOOTES-network optical upper limits
  80. GRB 220412B: BOOTES-1 optical upper limit
  81. GRB 220412A: Swift-BAT refined analysis
  82. GRB 220412A: RATIR Observations of the Fading Afterglow
  83. GRB 220412B: Swift-XRT observations
  84. GRB 220408B: Fermi-LAT detection
  85. IPN triangulation of short/soft GRB 220406A
  86. Swift GRB 220412B: Global MASTER-Net observations report
  87. GRB 220408A: HCT optical upper limit
  88. GRB 220412B: GIT optical upper limit
  89. GRB 220412A: MITSuME Akeno optical upper limits
  90. Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
  91. GRB 220412B: MITSuME Akeno optical upper limits
  92. GRB 220412A: Swift-XRT refined Analysis
  93. GRB 220412A: Enhanced Swift-XRT position
  94. GRB 220412B: Swift detection of a short burst
  95. GRB 220412A: Swift/UVOT Upper Limits
  96. GRB 220408A: GRANDMA observations
  97. GRB 220403B: GRANDMA observations
  98. GRB 220412A: RATIR Afterglow Candidate
  99. GRB 220412A: Swift detection of a burst
  100. GRB 220411A: AstroSat CZTI detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov