Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
New! BOOM Notices and Schema v7.0.0. 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. IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 220501A: Swift-BAT refined analysis
  3. Fermi-LAT Gamma-ray Observations of IceCube-220501A
  4. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  5. GRB 220501A: BOOTES-1 optical upper limit
  6. IceCube-220501A: No Candidate Counterparts from the Zwicky Transient Facility
  7. GRB 220501A: Fermi GBM observation
  8. GRB 220430A: AstroSat CZTI detection
  9. IceCube-220501A - IceCube observation of a high-energy neutrino candidate track-like event
  10. IceCube Alert 220501.95: Global MASTER-Net observations report
  11. GRB 220501A: GRANDMA/TJML Optical Observations
  12. GRB 220501A: Fermi GBM Final Real-time Localization
  13. GRB 220501A: Swift detection of a burst
  14. GRB 220430A: Swift-BAT refined analysis
  15. GRB 220430A: CAHA 2.2m telescope optical limit
  16. GRB 220430A: Swift-XRT refined Analysis
  17. Swift GRB 220430A: Global MASTER-Net observations report
  18. GRB 220430A: GRANDMA observations
  19. GRB 220430A: Mondy and AbAO optical upper limits
  20. GRB 220430A: AGILE detection
  21. GRB 220430A: MeerLICHT optical upper limits
  22. GRB 220430A: Enhanced Swift-XRT position
  23. GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
  24. IceCube-220425A: Upper limits from a search for additional neutrino events in IceCube
  25. IceCube-220424A: Upper limits from a search for additional neutrino events in IceCube
  26. IceCube-220421A: Upper limits from a search for additional neutrino events in IceCube
  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-LAT Gamma-ray Observations of IceCube-220425A
  43. Fermi GRB 220426B: Global MASTER-Net observations report
  44. GRB 220426B: Fermi GBM Final Real-time Localization
  45. GRB 220426A: BALROG localization (Fermi Trigger 672648596/ GRB 220426285)
  46. Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
  47. IceCube-220425A: MASTER: flaring blazar TXS 1742-078 as the possible neutrino source candidate
  48. Fermi-LAT Gamma-ray Observations of IceCube-220424A
  49. IceCube Alert 220425.11: Global MASTER-Net observations report
  50. Fermi trigger No 672492774: Global MASTER-Net observations report
  51. IceCube-220425A - IceCube observation of a high-energy neutrino candidate track-like event
  52. GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
  53. IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event
  54. IceCube Alert 220424.05: Global MASTER-Net observations report
  55. Fermi trigger No 672374264: Global MASTER-Net observations report
  56. On the AGILE detection of GRB 220423A
  57. GRB 220423A: AGILE detection
  58. GRB 220421B: Detection by VZLUSAT-2
  59. GRB 220421A: Fermi GBM observation
  60. Fermi-LAT Gamma-ray Observations of IceCube-220421A
  61. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  62. Fermi trigger No 672221879: Global MASTER-Net observations report
  63. Fermi GBM trigger 672128054/220420260 is not a GRB
  64. IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
  65. GRB 220418B: Swift-XRT observations
  66. IceCube Alert 220421.22: Global MASTER-Net observations report
  67. GRB 220418B Fermi GBM observation
  68. Fermi trigger No 672093919: Global MASTER-Net observations report
  69. “GRB 220420A” is not a GRB
  70. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  71. GRB 220403C: Further Swift-XRT observations
  72. GRB 220418B: Swift ToO observations
  73. GRB 220417A: Fermi GBM detection
  74. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  75. IPN triangulation of GRB 220411A
  76. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  77. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  78. GRB 220412B: Swift/UVOT Upper Limits
  79. Fermi GRB 220418A: Global MASTER-Net observations report
  80. GRB 220418B: Fermi GBM Final Real-time Localization
  81. GRB 220418A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 220417A: Global MASTER-Net observations report
  83. GRB 220417A: Fermi GBM Final Real-time Localization
  84. Fermi trigger No 671729344: Global MASTER-Net observations report
  85. GRB 220412B: Swift-BAT refined analysis
  86. Konus-Wind detection of GRB 220412B
  87. GRB 220412B: Fermi GBM observation
  88. Konus-Wind detection of GRB 220403C
  89. GRB 220408B: Fermi GBM observation
  90. Konus-Wind detection of GRB 220408B
  91. GRB 220412B: TNG optical observations
  92. GRB 220412A: GRANDMA observations
  93. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  94. GRB 220412A: BOOTES-network optical upper limits
  95. GRB 220412B: BOOTES-1 optical upper limit
  96. GRB 220412A: Swift-BAT refined analysis
  97. GRB 220412A: RATIR Observations of the Fading Afterglow
  98. GRB 220412B: Swift-XRT observations
  99. GRB 220408B: Fermi-LAT detection
  100. IPN triangulation of short/soft GRB 220406A

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