Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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. Fermi trigger No 695057654: Global MASTER-Net observations report
  2. IceCube-221223A: JCMT/SCUBA2 observations
  3. GRB 230102A: Fermi GBM Observation
  4. Fermi Gamma-ray Burst Monitor trigger 694043024/221229905 is not a GRB
  5. GRB 221231A: 3.6m DOT optical upper limit
  6. GRB 230104A: AGILE/MCAL detection of a burst
  7. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  8. GRB 221231A: Fermi GBM Observation
  9. GRB 221230A: CALET Gamma-Ray Burst Monitor detection
  10. Fermi Gamma-ray Burst Monitor trigger 694259491/230101411 is not a GRB
  11. GRB 230102A: Detection by GRBAlpha
  12. Fermi Gamma-ray Burst Monitor trigger 694302022/230101903 is not a GRB
  13. GRB 230101A: AstroSat CZTI detection
  14. Fermi trigger No 694259491: Global MASTER-Net observations report
  15. GRB 221231A: Swift-XRT afterglow detection
  16. GRB 230102A: AGILE/MCAL detection
  17. GRB 230102A: Fermi GBM Final Real-time Localization
  18. GRB 221231A: AKO Upper Limit
  19. GRB 221231A: Swift-XRT observations
  20. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  21. GRB 221231A: Swift ToO observations
  22. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  23. Fermi trigger No 694232203: Global MASTER-Net observations report
  24. GRB 230101A: Fermi GBM Final Real-time Localization
  25. GRB 221231A: Fermi GBM Final Real-time Localization
  26. Subject: IceCube-Cascade 221229A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube-221229A: Upper limits from a search for additional neutrino events in IceCube
  28. Fermi-LAT gamma-ray observations of IceCube-221229A
  29. GRB 221226A: Fermi GBM detection
  30. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  31. IPN triangulation of GRB 221226A
  32. IceCube-221229A - IceCube observation of a high-energy neutrino candidate track-like event
  33. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  34. ZTF22acaruqr/AT2022adzb: Neil Gehrels Swift Observatory X-ray detection
  35. GRB 221226B: LCOGT Optical Upper Limits
  36. IceCube-221224A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  38. GRB 221228A: Fermi GBM Final Real-time Localization
  39. GRB 221226B Swift-BAT refined analysis
  40. GRB 221226B: Swift-UVOT Detection
  41. GRB 221226A: AGILE detection
  42. GRB 221226B: Fermi GBM Observation
  43. GRB 221226B: Swift-XRT refined Analysis
  44. GRB 221226B: VLT/X-shooter redshift and host galaxy
  45. GRB 221226B: Enhanced Swift-XRT position
  46. GRB 221226B: Swift detection of a burst
  47. GRB 221226B: Fermi GBM Final Real-time Localization
  48. Swift GRB221226.95: Global MASTER-Net observations report
  49. Fermi GRB 221226A: Global MASTER-Net observations report
  50. GRB 221226A: Fermi GBM Final Real-time Localization
  51. Fermi-LAT gamma-ray observations of IceCube-221224A
  52. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  53. IceCube-221223A: BOOTES-4/MET Optical Observations
  54. Fermi-LAT gamma-ray observations of IceCube-221223A
  55. Fermi GRB 221223A: Global MASTER-Net observations report
  56. IceCube Alert 221224.04: Global MASTER-Net observations report
  57. IceCube-221224A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 221223A: Fermi GBM Final Real-time Localization
  59. IceCube Alert 221223.32: Global MASTER-Net observations report
  60. IceCube-221223A - IceCube observation of a high-energy neutrino candidate track-like event
  61. GRB 221221A: AGILE detection
  62. Fermi GRB 221221A: Global MASTER-Net observations report
  63. GRB 221221A: Fermi GBM Final Real-time Localization
  64. GRB 221218A: 3.6m DOT optical upper limit
  65. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  66. GRB 221216A: Detection by VZLUSAT-2
  67. GRB 221218A: MITSuME Akeno optical upper limits
  68. GRB 221218A: BOOTES-4/MET and OSN optical upper limits
  69. GRB 221218A: KAIT Optical Upper Limit
  70. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  71. GRB 221215A: Fermi GBM Detection
  72. GRB 221218A: a long GRB detected by INTEGRAL
  73. Integral GRB221218.34: Global MASTER-Net observations report
  74. Fermi-LAT gamma-ray observations of IceCube-221216A
  75. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  76. GRB 221216A: Swift/UVOT Upper Limits
  77. GRB 221216A: Fermi GBM observation
  78. GRB 221216A: Swift-XRT refined Analysis
  79. Fermi-LAT gamma-ray observations of IceCube-221210A
  80. IceCube Alert 221216.25: Global MASTER-Net observations report
  81. GRB 221216A: AKO Upper Limit
  82. GRB 221215A: Swift-XRT observations
  83. GRB 221216A: Enhanced Swift-XRT position
  84. Swift GRB 221216A: Global MASTER-Net observations report
  85. GRB 221216A: Zadko observatory - Gingin optical observations
  86. GRB 221216A: Nanshan/NEXT optical upper limits
  87. GRB 221216A: Swift detection of a burst
  88. GRB 221216A: Fermi GBM Final Real-time Localization
  89. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  90. Fermi trigger No 692760884: Global MASTER-Net observations report
  91. GRB 221215A: Swift ToO observations
  92. GRB 221215A: Swift/BAT-GUANO arcminute localization
  93. Konus-Wind detection of GRB 221209A
  94. Fermi GRB 221215B: Global MASTER-Net observations report
  95. IPN triangulation of GRB 221209A (long)
  96. GRB 221215B: Fermi GBM Final Real-time Localization
  97. Fermi Gamma-ray Burst Monitor trigger 692760884/221215066 is not a GRB
  98. Swift GRB221215.15: Global MASTER-Net observations report
  99. Fermi trigger No 692713692: Global MASTER-Net observations report
  100. GRB 221215A: Fermi GBM Final Real-time Localization

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