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"

36384 results found.

  1. GRB 230228A: Enhanced Swift-XRT position
  2. GRB 230228A: Nanshan/NEXT optical upper limit
  3. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  4. GRB 230228A: Prompt enhanced Swift-XRT position
  5. GRB 230228A: Swift detection of a possibly short burst
  6. Fermi GRB 230227A: Global MASTER-Net observations report
  7. GRB 230227A: Fermi GBM Final Real-time Localization
  8. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  9. GRB 230216A Mondy Observations
  10. GRB 230205A: VLA radio afterglow confirmation
  11. GRB 230217A: Swift/UVOT Upper Limits
  12. GRB 230216A: Swift/UVOT Upper Limits
  13. GRB 230217A: Continued Gemini Observations
  14. GRB 230220A: Correction to GCN 33352
  15. GRB 230222A: Fermi GBM Final Real-time Localization
  16. GRB 230217A: Swift-XRT afterglow detection
  17. GRB 230217A: Swift-BAT refined analysis
  18. Fermi GRB 230220B: Global MASTER-Net observations report
  19. GRB 230217A: AstroSat CZTI detection
  20. GRB 230217A: Gemini South optical upper limits
  21. GRB 230216B: CALET Gamma-Ray Burst Monitor detection
  22. GRB 230217A: 6 GHz VLA observations
  23. GRB 230220B: Fermi GBM Final Real-time Localization
  24. GRB 230217A: Gemini-South Optical Observation
  25. GRB 230217A: Fermi GBM observation
  26. GRB 230220A: MAXI/GSC detection
  27. Konus-Wind detection of GRB 230217A
  28. GRB 230217A: Swift-XRT observations
  29. GRB 230218A is not a GRB
  30. GRB 230218A: Fermi GBM Final Real-time Localization
  31. GRB 230217A: AGILE/MCAL detection
  32. GRB 230207B: CALET Gamma-Ray Burst Monitor detection
  33. GRB 230216B: AstroSat CZTI detection
  34. GRB 230216A: SVOM/C-GFT optical upper limit
  35. GRB 230217A: Swift detection of a short burst
  36. GRB 230217A: Fermi GBM Final Real-time Localization
  37. GRB 230216A: Swift-BAT refined analysis
  38. GRB 230216A: Swift-XRT refined Analysis
  39. GRB 230205A: Lowell Discovery Telescope Observations
  40. GRB 230204B: Lowell Discovery Telescope Observations
  41. Swift GRB 230216A: Global MASTER-Net observations report
  42. GRB 230216A: Enhanced Swift-XRT position
  43. GRB 230216A: AKO Upper Limit
  44. GRB 230216A: Zadko observatory - Gingin optical observations
  45. GRB 230216A: Swift detection of a burst
  46. Fermi GRB 230215A: Global MASTER-Net observations report
  47. GRB 230215A: Fermi GBM Final Real-time Localization
  48. GRB 230209B: AGILE detection
  49. GRB 230209B: Fermi GBM Observation
  50. IPN triangulation of GRB 230209B
  51. GRB 230204B: CALET Gamma-Ray Burst Monitor detection
  52. GRB 230204B: ATCA radio detection
  53. 230211A is not a GRB
  54. GRB 230211A: Fermi GBM Final Real-time Localization
  55. GRB 230209B: Swift/BAT-GUANO detection outside the coded FOV
  56. Swift Trigger 1153670 is probably not a GRB
  57. GRB 230210A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 230209B: Global MASTER-Net observations report
  59. GRB 230209B: Fermi GBM Final Real-time Localization
  60. GRB 230205A: 6 GHz VLA observations
  61. GRB 230209A is not a GRB
  62. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  63. GRB 230209A: Fermi GBM Final Real-time Localization
  64. GRB 221009A: Continued Swift Observations
  65. Fermi Gamma-ray Burst Monitor trigger 230208382/697540213 is not a GRB
  66. GRB 230207B: Detection by GRBAlpha
  67. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  68. GRB 230204B: MASTER early OT detection
  69. GRB 230208A: Fermi GBM Final Real-time Localization
  70. Fermi Gamma-ray Burst Monitor triggers 230206723/697396830 and 230206797/697403223 are not GRBs
  71. GRB 230207B: Swift/BAT-GUANO detection outside the coded FOV
  72. GRB 230207B: AGILE detection of a burst
  73. Fermi GRB 230207A: Global MASTER-Net observations report
  74. GRB 230207A: Fermi GBM Final Real-time Localization
  75. GRB 230204B: LCOGT Optical Upper Limits
  76. GRB 230204B: Swift/UVOT Upper Limits
  77. GRB 230205A: Swift/UVOT Upper Limits
  78. GRB 230204B: Fermi GBM detection
  79. GRB 230205A: LCOGT Optical Upper Limits
  80. GRB 230204B: Swift-XRT afterglow detection
  81. GRB 230204B: 3.6m DOT optical observation
  82. GRB 230205A: SVOM/C-GFT optical upper limit
  83. GRB 230205A: OHP/T193 optical observations
  84. GRB 230204B: VLT/X-shooter redshift
  85. GRB 230205A: Swift-BAT refined analysis (T90 = 2.3 s)
  86. GRB 230204A: Swift-BAT refined analysis
  87. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  88. GRB 230205A: Swift-XRT refined Analysis
  89. GRB 230204B: Swift ToO observations
  90. GRB 230205A: Enhanced Swift-XRT position
  91. GRB 230205A: BOOTES-5/JGT early optical upper limit
  92. GRB 230204B: Detection by GRBAlpha
  93. GRB 230204B: AGILE detection
  94. GRB 230205A: Swift detection of a burst
  95. GRB 230204B: GIT discovery of the likely optical afterglow
  96. GRB 230204B: AstroSat CZTI detection
  97. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  98. GRB 230204A: Swift/UVOT Upper Limits
  99. GRB 230204B: MAXI/GSC detection
  100. GRB 230204A: Swift-XRT refined Analysis

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