Skip to main content
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. GRB 240207A: Fermi GBM Final Real-time Localization
  2. Konus-Wind detection of GRB 240125A
  3. GRB 240205B: VLT/X-shooter redshift
  4. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  5. GRB 240205B: BOOTES-6 optical afterglow follow-up
  6. GRB 240205B: ATCA detection of radio counterpart
  7. GRB 240205B: REM detection of the optical/NIR afterglow
  8. GRB 240205B: Fermi GBM Observation
  9. GRB 240204A: AstroSat CZTI detection
  10. GRB 240204A: Mondy optical afterglow observations
  11. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  12. GRB 240205B: GECAM detection of a long burst
  13. GRB 240204A: Swift-BAT refined analysis
  14. GRB 240205B: Skynet Optical Afterglow Observations
  15. GRB 240205B: BOOTES-7 optical afterglow follow-up
  16. Fermi trigger No 728749569: Global MASTER-Net observations report
  17. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  18. GRB 240205B: Swift detection of a burst
  19. GRB 240205B: Fermi GBM Final Real-time Localization
  20. Swift GRB240205.93: Global MASTER-Net observations report
  21. GRB 240204A: Fermi GBM Observation
  22. GRB 240205A: Fermi GBM Final Real-time Localization
  23. GRB 240204a: Liverpool Telescope optical afterglow detection
  24. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  25. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  26. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  27. Fermi trigger No 728796365: Global MASTER-Net observations report
  28. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  29. GRB 240204A: Montarrenti Observatory optical observations
  30. GRB 240204A: Enhanced Swift-XRT position
  31. GRB 240204A: Mondy optical afterglow candidate
  32. Fermi Gamma-ray Burst Monitor trigger 728706420/240204102 is not a GRB
  33. Fermi GRB 240204A: Global MASTER-Net observations report
  34. Fermi trigger No 728706420: Global MASTER-Net observations report
  35. GRB 240204A: Swift detection of a burst
  36. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  37. GRB 240204A: Fermi GBM Final Real-time Localization
  38. IceCube Alert 240204.38: Global MASTER-Net observations report
  39. Swift Trigger 1212791 is not an astrophysical event.
  40. Swift-BAT triggers 1212787, 1212789 are not astrophysical.
  41. GRB 230812B: Update on Bad Time Intervals for Fermi GBM data
  42. Konus-Wind detection of GRB 240124B
  43. Konus-Wind detection of GRB 240123C
  44. IPN triangulation of GRB 240124B
  45. GRB 240201A: AstroSat CZTI detection
  46. GRB 240129A: Fermi GBM Observation
  47. IPN triangulation of GRB 240125B (short)
  48. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  49. IPN triangulation of GRB 240125A (short)
  50. GRB 240128A: Glowbug gamma-ray detection
  51. GRB 240128A: Swift-XRT observations
  52. GRB 240128A: GRBAlpha detection
  53. GRB 240128A: Tiled Swift observations
  54. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  55. GRB 240128A: MAXI/GSC detection
  56. GRB 240125A: GRBAlpha detection
  57. Fermi GRB 240127A: Global MASTER-Net observations report
  58. GRB 240123C: GRBAlpha detection
  59. GRB 240122A: ATCA detection of radio counterpart
  60. GRB 240127A: Fermi GBM Final Real-time Localization
  61. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 240125A: CALET Gamma-Ray Burst Monitor detection
  63. Swift Trigger 1211211 and 1211212 are not astrophysical
  64. GRB 240125A: AstroSat CZTI detection of a short burst
  65. GRB 240124B: AstroSat CZTI detection
  66. GRB 240123C: AstroSat CZTI detection
  67. GRB 240125B: Fermi GBM Final Localization
  68. GRB240122A: PRIME near infrared detection
  69. GRB 240123B: Fermi GBM Observation
  70. GRB 240123A: Glowbug gamma-ray detection
  71. GRB 240125A (short): Glowbug gamma-ray detection
  72. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  73. GRB 240123A: GRBAlpha detection
  74. IPN triangulation of GRB 240123C (short)
  75. Swift trigger 1210856 is not astrophysical
  76. Fermi-LAT gamma-ray observations of IceCube-240123A
  77. GRB 240123A: further SAO RAS optical observations
  78. GRB 240122B: CALET Gamma-Ray Burst Monitor detection
  79. GRB 240123A: Swift-BAT refined analysis
  80. IceCube Alert 240123.48: Global MASTER-Net observations report
  81. GRB 240123A: Mondy continued optical observations and the PL decay index
  82. GRB 240123A: SAO RAS optical observations
  83. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  84. Fermi/GBM trigger 727752941: BALROG analysis retraction
  85. GRB 240123A: Enhanced Swift-XRT position
  86. GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
  87. Fermi GRB 240123B: Global MASTER-Net observations report
  88. GRB 240122A: Swift/UVOT Upper Limits
  89. GRB 240123A: Swift-XRT refined Analysis
  90. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  91. Fermi GBM Sub-Threshold Detection of GRB 240123A
  92. GRB 240123A: Mondy continued optical observations + correction of the GRB name in GCN 35605
  93. GRB 240123B: Fermi GBM Final Real-time Localization
  94. GRB 240118A: Swift/UVOT Upper Limits
  95. GRB 240122B: Glowbug gamma-ray detection
  96. GRB 240123A: Mondy optical afterglow observations
  97. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  98. Konus-Wind detection of GRB 240112A
  99. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  100. Swift GRB240123.46: Global MASTER-Net observations report

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