Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
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. GRB 221215A: Swift-XRT observations
  2. GRB 221216A: Enhanced Swift-XRT position
  3. Swift GRB 221216A: Global MASTER-Net observations report
  4. GRB 221216A: Zadko observatory - Gingin optical observations
  5. GRB 221216A: Nanshan/NEXT optical upper limits
  6. GRB 221216A: Swift detection of a burst
  7. GRB 221216A: Fermi GBM Final Real-time Localization
  8. IceCube-221216A - IceCube observation of a high-energy neutrino candidate track-like event
  9. Fermi trigger No 692760884: Global MASTER-Net observations report
  10. GRB 221215A: Swift ToO observations
  11. GRB 221215A: Swift/BAT-GUANO arcminute localization
  12. Konus-Wind detection of GRB 221209A
  13. Fermi GRB 221215B: Global MASTER-Net observations report
  14. IPN triangulation of GRB 221209A (long)
  15. GRB 221215B: Fermi GBM Final Real-time Localization
  16. Fermi Gamma-ray Burst Monitor trigger 692760884/221215066 is not a GRB
  17. Swift GRB221215.15: Global MASTER-Net observations report
  18. Fermi trigger No 692713692: Global MASTER-Net observations report
  19. GRB 221215A: Fermi GBM Final Real-time Localization
  20. Swift Trigger 1144538 is not a GRB
  21. Fermi Gamma-ray Burst Monitor triggers 692721536/221214610 and 692713692/221214520 are not GRBs
  22. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 December 13
  23. Fermi trigger No 692607435: Global MASTER-Net observations report
  24. GRB 221209A: CALET Gamma-Ray Burst Monitor detection
  25. IceCube-221210A: Upper limits from a search for additional neutrino events in IceCube
  26. GRB 221212A: Fermi GBM Final Real-time Localization
  27. Fermi GRB 221211A: Global MASTER-Net observations report
  28. GRB 221208A: AstroSat CZTI detection
  29. GRB 221211A: Fermi GBM Final Real-time Localization
  30. IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event
  31. IceCube Alert 221210.36: Global MASTER-Net observations report
  32. GRB 221009A: MuSCAT3 observations
  33. GRB 221209A: AstroSat CZTI detection
  34. GRB 221210A: Fermi GBM Final Real-time Localization
  35. GRB 221209B: Fermi GBM Final Real-time Localization
  36. GRB 221209A: Fermi GBM observation
  37. GRB 221203C: AstroSat CZTI detection
  38. GRB 221209A: BALROG localization (Fermi Trigger 692257829 / GRB 221209243)
  39. GRB 221209A: Fermi GBM Final Real-time Localization
  40. GRB 221206B: Fermi GBM observation
  41. GRB 221206B: Swift-XRT observations
  42. GRB 221206B: Detection by GRBAlpha
  43. GRB 221206B: Swift/BAT-GUANO candidate arcminute localization
  44. GRB 221206B: Swift ToO observations
  45. Swift/BAT trigger #1143281 is not a GRB
  46. GRB 221206C: Fermi GBM Final Real-time Localization
  47. GRB 221206B: Fermi GBM Final Real-time Localization
  48. GRB 221206A: Fermi GBM Final Real-time Localization
  49. GRB 221205A: Fermi GBM Final Real-time Localization
  50. Swift GRB221204.45 AKO Upper Limit
  51. GRB 221202B: Detection by VZLUSAT-2
  52. Swift GRB221204.45: Global MASTER-Net observations report
  53. GRB 221203B: Fermi GBM Final Real-time Localization
  54. GRB 221202A: Swift/UVOT Detection
  55. GRB 221202A: Swift-BAT refined analysis
  56. GRB 221202A: VLT/FORS2 Afterglow Discovery
  57. GRB 221201A: Swift-BAT refined analysis
  58. GRB 221203A: Fermi GBM Final Real-time Localization
  59. GRB 221201A: Fermi GBM observation
  60. GRB 221202A: Swift-XRT refined Analysis
  61. GRB 221202A: LCOGT Optical Upper Limits
  62. GRB 221202A: Enhanced Swift-XRT position
  63. GRB 221202A: MeerLICHT upper limits
  64. GRB 221202B: Fermi GBM Final Real-time Localization
  65. GRB 221202A: Swift detection of a burst
  66. Swift GRB221202.84: Global MASTER-Net observations report
  67. GCN: GRB 221201A: Swift/UVOT Upper Limits
  68. GRB 221201A: Swift-XRT refined Analysis
  69. GRB 221201A: Enhanced Swift-XRT position
  70. Swift GRB 221201A: Global MASTER-Net observations report
  71. Konus-Wind detection of GRB 221124A
  72. GRB 221201A: Swift detection of a burst
  73. GRB 221201A: Fermi GBM Final Real-time Localization
  74. Fermi Gamma-ray Burst Monitor trigger 691534074/221130867 is not a GRB
  75. Optical polarization observation of GRB 221009A
  76. GRB 221126A: Fermi GBM observation
  77. IceCube-221124A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 221126A: AGILE detection
  79. GRB 221127A: Detection by GRBAlpha
  80. GRB 221126A: AstroSat CZTI detection
  81. IceCube-221124A: BOOTES-4/MET and BOOTES-2/TELMA optical upper limit
  82. Alert from the HAWC Burst Monitor HAWC-221128A
  83. GRB 221126A: Swift/BAT-GUANO detection outside the coded FOV
  84. IPN triangulation of GRB 221124A (long)
  85. GRB 221126A: Fermi GBM Final Real-time Localization
  86. GRB 221124A: Swift/BAT-GUANO detection
  87. Fermi-LAT gamma-ray observations of IceCube-221124A
  88. GRB 221120A: Detection by VZLUSAT-2
  89. GRB 221124A: CALET Gamma-Ray Burst Monitor detection
  90. IceCube-221124A - IceCube observation of a high-energy neutrino candidate track-like event
  91. IceCube Alert 221124.66: Global MASTER-Net observations report
  92. GRB 221120A: TURBO Optical Upper Limit
  93. GRB 221122A: Detection by GRBAlpha
  94. GRB 221120A: VIRT Optical Upper Limit
  95. Alert from the HAWC Burst Monitor HAWC-221123A
  96. GRB 221121A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 221009A：DAMPE observed a 34.7 GeV photon at 1.36 hour after the GBM trigger
  98. GRB 221120A: GTC Confirmation of an Underlying Galaxy
  99. IPN triangulation of GRB 221121A (long)
  100. GRB 221120A: Swift-BAT refined analysis

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