Skip to main content
End of Swift Science Operations, CHIME Notices Unavailable During Upgrade. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36386 results found.

  1. GRB 230204B: MAXI/GSC detection
  2. GRB 230204A: Swift-XRT refined Analysis
  3. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  4. GRB 230204A: Enhanced Swift-XRT position
  5. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  6. GRB 230201B: TURBO Optical Upper Limits
  7. Fermi Gamma-ray Burst Monitor trigger 230203275 / 697098930 is not a GRB
  8. GRB 221216A: Swift-BAT refined analysis
  9. Fermi GRB 230201B: Global MASTER-Net observations report
  10. GRB 230201B: Fermi GBM Final Real-time Localization
  11. GRB 230126A: Detection by VZLUSAT-2
  12. Fermi GRB 230201A: Global MASTER-Net observations report
  13. GRB 221009A: radio afterglow detection with the EVN
  14. GRB 230201A: Fermi GBM Final Real-time Localization
  15. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  16. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  17. AT2023avj: X-ray Detection with Swift/XRT
  18. GRB 230129A: AstroSat CZTI detection
  19. GRB 230128A: AstroSat CZTI detection
  20. GRB 230130A: Fermi GBM Final Real-time Localization
  21. GRB 230129A: Fermi GBM Final Real-time Localization
  22. GRB 230128A: Fermi GBM Final Real-time Localization
  23. AT2023avj ZTF Candidate: Assy optical observations
  24. GRB 230126A: Fermi GBM Final Real-time Localization
  25. GRB 230124A: Fermi GBM Observation
  26. GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
  27. GRB 230114B: Detection by VZLUSAT-2
  28. GRB 230123A: LCOGT Optical Upper Limits
  29. Fermi GRB 230124A: Global MASTER-Net observations report
  30. GRB 230124A: Fermi GBM Final Real-time Localization
  31. GRB 230123A: Swift-BAT refined analysis
  32. GRB 230122A: Swift/BAT-GUANO detection
  33. GRB 230123A: Swift/UVOT Upper Limits
  34. GRB 230123A: Swift-XRT refined Analysis
  35. GRB 230123A: Enhanced Swift-XRT position
  36. GRB 230123A: Zadko observatory - Gingin optical observations
  37. GRB 230116C: Swift-XRT observations
  38. GRB 230123A: Swift detection of a burst
  39. GRB 230116B: Fermi GBM observation
  40. GRB 230120A: AstroSat CZTI detection
  41. IPN triangulation of GRB 230116B (short)
  42. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  43. GRB 230116D: 3.6m DOT optical upper limit
  44. GRB 230119A: Fermi GBM Final Real-time Localization
  45. Fermi GRB 230118A: Global MASTER-Net observations report
  46. GRB 230118A: Fermi GBM Final Real-time Localization
  47. GRB 230116D: Swift-BAT refined analysis
  48. GRB 230116C: Swift-BAT refined analysis
  49. GRB 230116D: SAO RAS further observations
  50. GRB 230116D: SAO RAS photometry
  51. GRB 230116D: KGO RC-25 optical observations
  52. GRB 230116D: Sintez-Newton/CrAO optical observations
  53. GRB 230116D: LCOGT Optical Upper Limit
  54. GRB 230116D: SAO RAS redshift
  55. GRB 230116D: Swift-XRT refined Analysis
  56. Fermi GRB 230117A: Global MASTER-Net observations report
  57. GRB 230117A: Fermi GBM Final Real-time Localization
  58. GRB 230116D: GIT optical follow-up
  59. GRB 230116D: GIT optical follow-up
  60. GRB 230116D: Enhanced Swift-XRT position
  61. GRB 230116D: SAO RAS observations of OT brightening
  62. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  63. GRB 230116D: Nanshan/NEXT optical afterglow detection
  64. GRB 230116D: Swift detection of a burst
  65. GRB 230116C: Swift detection of a burst
  66. GRB 230116B: Fermi GBM Final Real-time Localization
  67. GRB 230116A: Fermi GBM Final Real-time Localization
  68. GRB 230114A: Detection by VZLUSAT-2
  69. GRB 230114A: Fermi GBM Final Real-time Localization
  70. GRB 230111A: Fermi GBM Observation
  71. Fermi GRB 230112A: Global MASTER-Net observations report
  72. GRB 230112A: Fermi GBM Final Real-time Localization
  73. GRB 230111A: MAXI/GSC detection
  74. GRB 230111A: Fermi GBM Final Real-time Localization
  75. GRB 230106: AstroSat LAXPC detection
  76. GRB 230102A: Fermi GBM Observation
  77. Fermi Gamma-ray Burst Monitor trigger 694043024/221229905 is not a GRB
  78. GRB 221231A: 3.6m DOT optical upper limit
  79. GRB 230104A: AGILE/MCAL detection of a burst
  80. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  81. GRB 221231A: Fermi GBM Observation
  82. GRB 221230A: CALET Gamma-Ray Burst Monitor detection
  83. Fermi Gamma-ray Burst Monitor trigger 694259491/230101411 is not a GRB
  84. GRB 230102A: Detection by GRBAlpha
  85. Fermi Gamma-ray Burst Monitor trigger 694302022/230101903 is not a GRB
  86. GRB 230101A: AstroSat CZTI detection
  87. GRB 221231A: Swift-XRT afterglow detection
  88. GRB 230102A: AGILE/MCAL detection
  89. GRB 230102A: Fermi GBM Final Real-time Localization
  90. GRB 221231A: AKO Upper Limit
  91. GRB 221231A: Swift-XRT observations
  92. GRB 221231A: Swift ToO observations
  93. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  94. GRB 230101A: Fermi GBM Final Real-time Localization
  95. GRB 221231A: Fermi GBM Final Real-time Localization
  96. GRB 221226A: Fermi GBM detection
  97. IPN triangulation of GRB 221226A
  98. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  99. GRB 221226B: LCOGT Optical Upper Limits
  100. GRB 221228A: Fermi GBM Final Real-time Localization

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