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"

27964 results found.

  1. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  2. Swift ToO Observations of HAWC transient J0020+3108
  3. GRB 210605B: Swift-XRT afterglow detection
  4. GRB 210610A: Fermi GBM observations
  5. GRB 210610A: CAHA 2.2m Second Epoch
  6. GRB 210610B: Continued KAIT Optical Detection
  7. GRB 210421B: Fermi GBM detection
  8. Swift GRB210612.54: Global MASTER-Net observations report
  9. GRB 210607C: AstroSat CZTI detection
  10. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  11. GRB210610B: SARA-KP 0.9m Optical Afterglow Detection
  12. GRB 210610B: MITSuME Akeno optical observation
  13. GRB 201228B: Fermi GBM observation
  14. GRB 210610B: VLA detection
  15. GRB 210610B: ALMA detection
  16. GRB 210610A: CAHA 2.2m observations and light-curve behavior
  17. GRB 210606A: Fermi GBM detection
  18. GRB 210605B: Fermi GBM detection
  19. GRB 210610B: Swift-XRT refined Analysis
  20. GRB 210610B: Swift-BAT refined analysis
  21. GRB 210610B: Zwicky Transient Facility afterglow detection
  22. GRB 210610B: KAIT Optical Detection
  23. GRB 210610A: KAIT Optical Detection
  24. GRB 210607C: Insight-HXMT/HE detection
  25. GRB 210610B: Spectroscopy and redshift confirmation with the Himalayan Chandra Telescope
  26. GRB 210610A: Spectroscopy and redshift confirmation with the Himalayan Chandra Telescope
  27. GRB 210610B: Fermi GBM detection
  28. GRB 210610B: University of Siena Observatory optical photometry of the afterglow
  29. Konus-Wind detection of GRB 210610A
  30. Konus-Wind detection of GRB 210610B
  31. GRB 210610B: AGILE detection
  32. GRB 210610B: GOTO confirmation of afterglow detection
  33. GRB 210610A: Swift-XRT refined Analysis
  34. GRB 210610A: RATIR Optical and NIR Detection
  35. GRB 210610B: RATIR Optical and NIR Observations
  36. GRB 210610B: Enhanced Swift-XRT position
  37. GRB 210610B: SAO RAS optical observations
  38. GRB 210610A: Swift-BAT refined analysis
  39. GRB 210610A: 1.5m OSN optical observation
  40. GRB210610B: MeerLICHT multi-colour photometry
  41. GRB 210610B: BOOTES-2/TELMA optical observation
  42. Swift GRB 210610B: Global MASTER-Net observations report
  43. GRB 210610B: GIT optical detection
  44. Swift GRB210610.83: Global MASTER-Net OT detection
  45. GRB 210606A: Swift-XRT afterglow detection
  46. GRB 210610B: Swift detection of a burst with bright optical afterglow
  47. GRB 210610A: MITSuME Ishigaki optical observation
  48. GRB210610A: MeerLICHT multi-colour photometry
  49. Swift GRB 210610A: Global MASTER-Net observations report
  50. Swift GRB 210610A: MASTER optical counterpart observation
  51. GRB 210610A: Enhanced Swift-XRT position
  52. GRB 210610A: Xinglong-2.16m redshift
  53. GRB 210610A: GIT optical detection
  54. GRB 210610A: Xinglong-2.16m optical afterglow observations
  55. GRB 210610A: MITSuME Akeno optical observation
  56. GRB 210610A: Swift detection of a burst with an optical counterpart
  57. GRB 210607B: Insight-HXMT/HE detection
  58. GRB 210605A: CALET Gamma-Ray Burst Monitor detection
  59. Konus-Wind detection of GRB 210606B
  60. IPN triangulation of GRB 210606B
  61. IceCube-210608A: IceCube observation of a high-energy neutrino candidate track-like event
  62. GRB 210607A/MAXI J1733-222: MAXI/GSC detection
  63. GRB 210606B: Fermi GBM detection
  64. GRB 210605B: Swift-XRT observations
  65. Konus-Wind detection of GRB 210602A
  66. Konus-Wind detection of GRB 210605A (short/hard)
  67. IPN triangulation of GRB 210605A (short)
  68. GRB 210606B: AGILE detection
  69. GRB 210606A: 1.5m OSN optical upper limit
  70. GECAM Sub-Threshold Detection of new magnetar Swift SGR J1555.2-5402
  71. GRB 210606B: GECAM detection
  72. GRB 210606A: Swift ToO observations
  73. GRB 210606A: Swift/BAT-GUANO detection and arcminute localization
  74. GRB 210605B: Swift ToO observations
  75. GRB 210606A: Fermi GBM Final Real-time Localization
  76. GRB 210605B: Swift/BAT-GUANO detection and arcminute localization
  77. GRB 210605B: Fermi GBM Final Real-time Localization
  78. GRB 210605A: Fermi GBM Final Real-time Localization
  79. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  80. Fermi GBM Sub-Threshold Detection of new Swift SGR J1555.2-5402
  81. SGR J1555.2-5402: Swift-BAT refined analysis
  82. Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
  83. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  84. Swift Detection of probable new Swift SGR J1555.2-5402
  85. Swift GRB210603.41: Global MASTER-Net observations report
  86. GRB 210602A: CALET Gamma-Ray Burst Monitor detection
  87. GRB 210602B: GECAM detection
  88. GRB 210529A: GECAM detection
  89. GRB 210602A: MAXI/GSC detection
  90. GRB 210601A: Fermi GBM Final Real-time Localization
  91. IPN triangulation of GRB 210531A
  92. GRB210529B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 644025222)
  93. GRB 210531A: AstroSat CZTI detection
  94. GRB 210531A: AGILE/MCAL detection (Fermi Trigger 644155206 / GRB 210531500)
  95. GRB 210529B: Fermi GBM Final Real-time Localization
  96. GRB 210529A: Fermi GBM Final Real-time Localization
  97. GRB 210528A: Fermi GBM detection
  98. GRB 210528A: AstroSat CZTI detection
  99. GRB 210528B: MAXI/GSC detection
  100. GRB 210527A: Swift-BAT 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