Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
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. IPN Triangulation of GRB 211019A
  2. Possible Short GRB 211023B: CAHA 2.2m Detection
  3. GRB 211025A: Swift/UVOT Detection
  4. GRB 211023A: 1.5m OSN optical observation
  5. GRB 211024B: Swift-BAT refined analysis
  6. GRB 210610B: Sintesz-Newton/CrAO optical observations
  7. GRB 211025A: Enhanced Swift-XRT position
  8. GRB 211025A: Swift detection of a burst
  9. GECAM detection of a short burst probably from SGR J1555.2-5402
  10. GRB 211024B: Nanshan/NEXT optical afterglow detection
  11. GRB 210919A: FORS2/VLT observations
  12. GRB 211023A: OAJ Bright Afterglow Confirmation
  13. Swift GRB 211024B: Global MASTER-Net observations report
  14. GRB 211024B: Swift detection of a burst
  15. GRB 211023B: Swift-BAT refined analysis
  16. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  17. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  18. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  19. GRB 211023B: Swift/UVOT Detection
  20. GRB 211024A: GECAM detection
  21. GRB 211023B: RATIR Optical and NIR Upper Limits
  22. GRB 211023B: TSHAO optical observation
  23. IceCube-211023A: No neutrino counterpart detected with ANTARES
  24. Fermi GRB 211023A: Global MASTER-Net observations report
  25. GRB 211023A: AGILE detection
  26. GRB 211022A: AstroSat CZTI detection
  27. GRB 211023B: Swift-XRT refined Analysis
  28. GRB 211023B: Enhanced Swift-XRT position
  29. GRB 211023A: Fermi GBM detection
  30. Swift GRB 211023B: Global MASTER-Net observations report
  31. Fermi GRB 211024A: Global MASTER-Net observations report
  32. GRB 211024A: Fermi GBM Final Real-time Localization
  33. GRB 211023A: Fermi-LAT detection
  34. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  35. IceCube Alert 211023.36: Global MASTER-Net observations report
  36. GRB 211023A: Fermi GBM Final Real-time Localization
  37. IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event
  38. IPN Triangulation of GRB 210927B
  39. GRB 211022A: GECAM detection
  40. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  41. GRB 211018A: Swift ToO observations
  42. GRB 211021A: BALROG localization (Fermi Trigger 656506979 / GRB 211021460)
  43. Fermi trigger No 656506979: Global MASTER-Net observations report
  44. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211020A
  45. BepiColombo MGNS joins the IPN
  46. Fermi trigger No 656268212: Global MASTER-Net observations report
  47. GRB 211018A: Fermi GBM observation
  48. GRB 211019A: Detection by GRBAlpha
  49. GRB 211018A: Detection by GRBAlpha
  50. Fermi GRB 211019A: Global MASTER-Net observations report
  51. GRB 211018A: Fermi-LAT detection
  52. GRB 211019A: BALROG localization (Fermi Trigger 656315976 / GRB 211019250)
  53. GRB 211019A: Fermi GBM Final Real-time Localization
  54. Fermi trigger No 656288898: Global MASTER-Net observations report
  55. Swift GRB211017.99: Global MASTER-Net observations report
  56. Integral GRB211016.42: Global MASTER-Net observations report
  57. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  58. Swift trigger 1078701: MITSuME Akeno optical upper limits
  59. Fermi trigger No 655673024: Global MASTER-Net observations report
  60. GRB 210919A: LDT optical observations and candidate host galaxies
  61. IceCube-20210922A: No optical counterparts found by MITSuME observations
  62. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  63. Fermi trigger No 655646385: Global MASTER-Net observations report
  64. Swift GRB211010.45: Global MASTER-Net observations report
  65. Swift Trigger 1078701 is probably not a GRB
  66. Fermi Gamma-ray Burst Monitor trigger 211008665/655401471 is not a GRB
  67. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  68. GRB 211008A: BALROG localization (Fermi Trigger 655401471 / GRB 211008665)
  69. Fermi trigger No 655401471: Global MASTER-Net observations report
  70. GRB 210928A: MeerKAT detection
  71. IceCube-210922A: DESI Observations
  72. GECAM observation of a burst from SGR J1555.2-5402
  73. Konus-Wind detection of GRB 210928A
  74. Fermi trigger No 654854799: Global MASTER-Net observations report
  75. Correction to GCN 30915: GRB 210928A: Swift-XRT analysis
  76. GRB 210928A: Kinder SLT-40cm optical limits
  77. GRB 210930A: Swift-BAT refined analysis
  78. SGR 1935+2154: Swift/BAT-GUANO detection and arcminute localization
  79. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  80. GRB 210928A: Swift-XRT refined Analysis
  81. GRB 210928A: Fermi GBM observation
  82. GRB 210928A: Fermi-LAT detection
  83. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  84. GRB 210927B: GECAM detection
  85. GRB 210930A: CAHA 2.2m telescope optical limit
  86. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  87. Fermi trigger No 654739449: Global MASTER-Net observations report
  88. Swift GRB211001.03: Global MASTER-Net observations report
  89. Swift Trigger 1076121 is not a GRB
  90. Swift GRB211001.03: Global MASTER-Net OT detection
  91. GRB 210930A: Swift/UVOT Upper Limits
  92. GRB 210930A: Swift-XRT refined Analysis
  93. Swift GRB 210930A: Global MASTER-Net observations report
  94. GRB 210930A: Enhanced Swift-XRT position
  95. Fermi trigger No 654658271: Global MASTER-Net observations report
  96. Fermi GRB 210929B: Global MASTER-Net observations report
  97. GRB 210930A: Swift detection of a burst
  98. GRB 210929B: Fermi GBM Final Real-time Localization
  99. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  100. GRB 210929A: Fermi GBM Final Real-time Localization

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