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"

19662 results found.

  1. GRB 210504A: AST3-3 YaoAn Optical Upper Limit
  2. GRB 210504A: Swift/UVOT Detection
  3. GRB 210504A: BOOTES-4/MET optical upper limit
  4. Swift GRB210504.58: Global MASTER-Net observations report
  5. GRB 210504A: update on the BAT trigger time and burst duration
  6. GRB 210504A: Swift detection of a burst
  7. Swift GRB210502.74: Global MASTER-Net observations report
  8. Swift Detection of MAXI J1803-298 including an optical counterpart
  9. GRB 210430A: BOOTES-1 optical limit
  10. GRB 210430A: Swift-BAT refined analysis
  11. Swift GRB210430.45: Global MASTER-Net observations report
  12. GRB 210430A: Swift detection of a burst
  13. GRB 210413B: Swift/UVOT Observations
  14. Delayed GRB GCN Notices from Swift
  15. GRB 210323B: Swift-XRT observations
  16. Swift Trigger 1045571 is not a GRB
  17. GRB 210422A: Swift-BAT refined analysis
  18. GRB 210421A: Swift-BAT refined analysis
  19. GRB 210421B: Swift-XRT observations
  20. GRB 210421B: AstroSat CZTI detection
  21. GRB 210421A: GECAM detection
  22. GRB 210421B: AstroSat CZTI detection
  23. Swift GRB210422.74: Global MASTER-Net observations report
  24. GRB 210422A: Swift detection of a burst
  25. GRB 210421A: Swift/UVOT Upper Limits
  26. GRB 210421A: MITSuME Akeno optical upper limits
  27. GRB 210420B: Swift-BAT refined analysis
  28. GRB 210421B: Swift ToO observations
  29. GRB 210421B: Swift/BAT-GUANO detection and arcminute localization
  30. GRB 210420B: Swift-XRT refined Analysis
  31. GRB 210421A: Swift-XRT refined Analysis
  32. GRB 210419C: Swift/UVOT Upper Limits
  33. GRB 210421A: Enhanced Swift-XRT position
  34. GRB 210420B: Swift/UVOT Detection
  35. GRB 210420B: KAIT Optical Observations
  36. GRB 210419C: MITSuME Akeno optical upper limits
  37. GRB 210420B: DDOTI Detection of the Afterglow
  38. GRB 210421A: DDOTI Upper Limit
  39. GRB 210419C: Swift-BAT refined analysis
  40. GRB 210420B: update on the BAT trigger time
  41. GRB 210420B: Montarrenti Observatory optical afterglow detection
  42. Swift GRB 210421A: Global MASTER-Net observations report
  43. GRB 210421A: Swift detection of a burst
  44. GRB 210420B: AST3-3 YaoAn Optical Observation
  45. GRB 210420B: BOOTES-4/MET optical afterglow detection
  46. GRB 210420B: Optical observations
  47. GRB 210420B: MASTER optical counterpart detection
  48. GRB 210420B: Swift detection of a burst
  49. GRB 210419C: Montarrenti Observatory Upper Limit
  50. GRB 210419A: Swift/UVOT Upper Limits
  51. GRB 210419C: KAIT Optical Upper Limit
  52. GRB 210419C: Enhanced Swift-XRT position
  53. GRB 210419A: Swift-BAT refined analysis
  54. Swift GRB210419.98: Global MASTER-Net observations report
  55. GRB 210419A: Swift-XRT refined Analysis
  56. GRB 210419C: Swift detection of a burst
  57. Swift GRB 210419A: Global MASTER-Net observations report
  58. GRB 210419A: Enhanced Swift-XRT position
  59. GRB 210419A: LCO Optical Upper Limit
  60. GRB 210419A: Swift detection of a burst
  61. GRB 210413B: Swift-XRT observations
  62. GRB 210413B: LOAO optical upper limit
  63. GRB 210411C: A very significant early X-ray afterglow
  64. GRB 210413B: Swift ToO observations
  65. GRB 210413B: Swift/BAT detection and probable localization of a short burst
  66. GRB 210410A: AstroSat CZTI detection
  67. GRB 210410A: A twin of short GRB 090510 with complementary observations
  68. GRB 210410A: Swift/UVOT Upper Limits (revision)
  69. GRB 210411C: Swift/UVOT Detection
  70. GRB 210411C: Swift-BAT refined analysis
  71. GRB 210411C: Chilescope optical observations
  72. GRB 210411C: Swift-XRT refined Analysis
  73. Swift GRB 210411C: Global MASTER-Net observations report
  74. GRB 210411C: BOOTES-4/MET optical upper limit
  75. GRB 210411C: LCO Optical Afterglow Candidate
  76. GRB 210411C: Enhanced Swift-XRT position
  77. GRB 210406A: 10.4m GTC follow-up observation
  78. Konus-Wind detection of GRB 210410A
  79. GRB 210411C: Swift detection of a burst with an optical counterpart
  80. GRB 210410A: Swift-BAT refined analysis
  81. GRB 210410A: Swift-XRT refined Analysis
  82. GRB 210410A: Fermi GBM detection
  83. GRB 210410A: Swift/UVOT Upper Limits
  84. GRB 210406A: Swift-XRT observations
  85. GRB 210410A: RATIR Optical and NIR Observations
  86. GRB 210410A: AGILE detection of a burst
  87. GRB 210410A: Fermi-LAT detection
  88. GRB210410A: Candidate optical afterglow by Ondrejov D50
  89. GRB 210410A: Swift XRT localization
  90. Swift Triggers 1042031 and 1042032 are not astrophysical events
  91. GRB 210406A: Swift ToO observations
  92. GRB 210402A: MASTER prompt and follow up optical observation
  93. GRB 210402A: Swift/UVOT Upper Limits
  94. GRB 210402A: Fermi GBM detection
  95. GRB 210402A: Swift-BAT refined analysis
  96. GRB 210207B: Prompt and very late time observations with HCT.
  97. GRB 210402A: NOT optical afterglow candidate
  98. GRB 210402A: BOOTES-network early optical upper limit
  99. GRB 210403A: Swift-BAT refined analysis
  100. GRB 210402A: LBT observations

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