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"
  1. IceCube-220513A: No significant detection in HAWC
  2. GRB 220514B: MAXI/GSC detection
  3. MAXI GRB220514.98: Global MASTER-Net observations report
  4. GRB 220514A: MeerLICHT optical afterglow candidate
  5. Integral GRB220514.52: Global MASTER-Net observations report
  6. Fermi GRB 220514A: Global MASTER-Net observations report
  7. GRB 220514A: a long GRB detected by INTEGRAL
  8. IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
  9. GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
  10. GRB 220514A: Fermi GBM Final Real-time Localization
  11. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  12. IceCube Alert 220513.97: Global MASTER-Net observations report
  13. Fermi GRB 220513A: Global MASTER-Net observations report
  14. GRB 220513A: Fermi GBM Final Real-time Localization
  15. Konus-Wind detection of GRB 220511A
  16. GRB 220427A: MeerLICHT afterglow observations
  17. IceCube-220509A: No significant detection in HAWC
  18. GRB 220511A: Fermi GBM observation
  19. GRB 220511A: Swift-XRT observations
  20. GRB 220511A: AstroSat CZTI detection
  21. GRB 220511A: BOOTES-2/TELMA optical upper limit
  22. Fermi GRB 220512A: Global MASTER-Net observations report
  23. GRB 220512A: Fermi GBM Final Real-time Localization
  24. GRB 220511A: Swift ToO observations
  25. GRB 220511A: Swift/BAT-GUANO arcminute localization
  26. Fermi GRB 220511A: Global MASTER-Net observations report
  27. GRB 220511A: AGILE detection
  28. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 220511A: BALROG localization (Fermi Trigger 673969321/ GRB 220511571)
  30. GRB 220511A: Fermi GBM Final Real-time Localization
  31. GRB 220507A: AstroSat CZTI detection
  32. Fermi-LAT Gamma-ray Observations of IceCube-220509A
  33. Fermi trigger No 673846271: Global MASTER-Net observations report
  34. GRB 220506A: MITSuME Akeno optical upper limits
  35. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 220506A: GIT optical upper limit.
  37. IceCube Alert 220509.76: Global MASTER-Net observations report
  38. GRB 220508A: Fermi GBM Final Real-time Localization
  39. GRB 220507A: Fermi GBM Final Localization
  40. GRB 220506A: BOOTES-5/JGT optical upper limit
  41. Fermi trigger No 673610950: Global MASTER-Net observations report
  42. GRB 220506A: Swift-XRT afterglow detection
  43. GRB 220506A: Tiled Swift observations
  44. IceCube-220405B - ZTF19aavnpjv unrelated
  45. Swift-BAT triggers 1105560-1 are not GRBs
  46. Swift GRB220506.51: Global MASTER-Net observations report
  47. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  48. MAXI GRB220506.27: Global MASTER-Net observations report
  49. GRB 220430A: Nanshan/NEXT optical upper limit
  50. GRB 220430A: Nanshan/HMT optical upper limit
  51. GRB 220430A: GIT optical upper limits
  52. IPN triangulation of GRB 220423A
  53. GRB 220427A: LCO Optical Observations
  54. IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 220501A: Swift-BAT refined analysis
  56. Fermi-LAT Gamma-ray Observations of IceCube-220501A
  57. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  58. GRB 220501A: BOOTES-1 optical upper limit
  59. IceCube-220501A: No Candidate Counterparts from the Zwicky Transient Facility
  60. GRB 220501A: Fermi GBM observation
  61. GRB 220430A: AstroSat CZTI detection
  62. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube Alert 220501.95: Global MASTER-Net observations report
  64. GRB 220501A: GRANDMA/TJML Optical Observations
  65. GRB 220501A: Fermi GBM Final Real-time Localization
  66. GRB 220501A: Swift detection of a burst
  67. GRB 220430A: Swift-BAT refined analysis
  68. GRB 220430A: CAHA 2.2m telescope optical limit
  69. GRB 220430A: Swift-XRT refined Analysis
  70. Swift GRB 220430A: Global MASTER-Net observations report
  71. GRB 220430A: GRANDMA observations
  72. GRB 220430A: Mondy and AbAO optical upper limits
  73. GRB 220430A: AGILE detection
  74. GRB 220430A: MeerLICHT optical upper limits
  75. GRB 220430A: Enhanced Swift-XRT position
  76. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
  77. IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
  79. IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 220427A: Swift-BAT refined analysis
  81. GRB 220427A: VLT/X-shooter photometry
  82. GRB 220426A: Swift-XRT and UVOT observations
  83. GRB 220423A: Detection by VZLUSAT-2
  84. Konus-Wind detection of GRB 220427A
  85. GRB 220427A: Swift-XRT refined Analysis
  86. GRB 220427A: Enhanced Swift-XRT position
  87. GRB 220426A: Tiled Swift observations
  88. GRB 220427A: Swift detection of a burst with an optical counterpart
  89. Konus-Wind detection of GRB 220426A
  90. IPN triangulation of GRB 220426A
  91. GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
  92. Fermi GRB 220426A: Global MASTER-Net observations report
  93. GRB 220426A: Fermi GBM detection
  94. GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
  95. Fermi-LAT Gamma-ray Observations of IceCube-220425A
  96. Fermi GRB 220426B: Global MASTER-Net observations report
  97. GRB 220426B: Fermi GBM Final Real-time Localization
  98. GRB 220426A: BALROG localization (Fermi Trigger 672648596/ GRB 220426285)
  99. Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
  100. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate

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