Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

5057 results found.

  1. GRB 210731A: Swift detection of a burst
  2. Trigger 1062273: Swift detection of 4U 1700-377
  3. Fermi trigger No 649390368: Global MASTER-Net observations report
  4. Fermi GBM Sub-Threshold Detection of GRB 210726A
  5. Fermi trigger No 649072251: Global MASTER-Net observations report
  6. GRB 210726A: Swift detection of a burst
  7. Fermi trigger No 648959581: Global MASTER-Net observations report
  8. GRB 210725A: Fermi GBM detection
  9. GRB 210725A: CALET Gamma-Ray Burst Monitor detection
  10. Fermi trigger No 648868114: Global MASTER-Net observations report
  11. GRB 210725A: Swift detection of a burst
  12. Swift GRB210725.16: Global MASTER-Net observations report
  13. GRB 210702A: ALMA detection of mm-band rebrightening
  14. Fermi trigger No 648602917: Global MASTER-Net observations report
  15. Fermi trigger No 647942198: Global MASTER-Net observations report
  16. Fermi trigger No 647805873: Global MASTER-Net observations report
  17. Fermi trigger No 647522278: Global MASTER-Net observations report
  18. Fermi GRB 210709A: Global MASTER-Net observations report
  19. GRB 210702A: ALMA detection
  20. GRB 210708B: Swift detection of a possible burst
  21. Fermi GBM Observations of SGR J1935+2154
  22. GRB 210704A: Fermi-LAT detection
  23. Fermi trigger No 647108723: Global MASTER-Net observations report
  24. Fermi trigger No 647120009: Global MASTER-Net observations report
  25. GRB 210702A: iTelescope optical afterglow observations
  26. Fermi GRB 210627B: Global MASTER-Net observations report
  27. Fermi GRB 210627A: Global MASTER-Net observations report
  28. Fermi trigger No 646322348: Global MASTER-Net observations report
  29. Fermi GRB 210626A: Global MASTER-Net observations report
  30. Fermi trigger No 646189108: Global MASTER-Net observations report
  31. GRB 210619B: Abbey Ridge Observatory optical afterglow observation
  32. Swift Trigger 1057131: detection of a burst from SGR Swift J1555.2-5402
  33. GRB 210619B: SAO RAS optical observations
  34. GRB 210621A: Fermi GBM Final Real-time Localization
  35. GRB 210619B: CAHA 2.2m photometric monitoring
  36. GRB 210619B: Liverpool Telescope r'-band observations
  37. GRB 210619B: Liverpool telescope imaging of a red afterglow
  38. Fermi trigger No 645857659: Global MASTER-Net observations report
  39. Swift GRB210619.99: Global MASTER-Net OT detection
  40. GRB 210618A: DDOTI upper limit for the optical afterglow
  41. GRB 210323B: Fermi GBM observation
  42. Fermi GRB 210615A: Global MASTER-Net observations report
  43. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  44. GRB 210610A: Fermi GBM observations
  45. GRB 210610B: iTelescope optical afterglow observations
  46. GRB 210610B: Further SAO RAS optical observations
  47. GRB 210610A: SAO RAS optical observations
  48. GRB 210610B: optical observations from Burke-Gaffney Observatory and Abbey Ridge Observatory
  49. GRB 210610B: optical photometry of afterglow at INASAN/Simeiz
  50. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  51. GRB 210606A: Fermi GBM detection
  52. Konus-Wind detection of GRB 210610A
  53. GRB 210610B: SAO RAS optical observations
  54. Fermi trigger No 645047470: Global MASTER-Net observations report
  55. GRB 210610A: Swift detection of a burst with an optical counterpart
  56. Fermi-LAT Gamma-ray Observations of IceCube-210608A
  57. IceCube-210608A: IceCube observation of a high-energy neutrino candidate track-like event
  58. IceCube Alert 210608.15: Global MASTER-Net observations report
  59. Konus-Wind detection of GRB 210602A
  60. GRB 210606B: AGILE detection
  61. GRB 210606A: Swift/BAT-GUANO detection and arcminute localization
  62. GRB 210606A: Fermi GBM Final Real-time Localization
  63. Initial results of a NICER X-ray monitoring of the magnetar, Swift J1555.2-5402
  64. SGR J1555.2-5402: Swift-BAT refined analysis
  65. Fermi trigger No 644449593: Global MASTER-Net observations report
  66. Swift J1555.2-5402: Swift XRT refined analysis of the new SGR
  67. NICER discovery of 3.86 s pulsations from a new magnetar: SGR J1555.2-5402
  68. Swift Detection of probable new Swift SGR J1555.2-5402
  69. MAXI GRB210602.50: Global MASTER-Net observations report
  70. Swift GRB210603.41: Global MASTER-Net observations report
  71. Fermi trigger No 644359567: Global MASTER-Net observations report
  72. GRB 210602A: MAXI/GSC detection
  73. GRB 210529B: DDOTI Upper Limits on the Afterglow
  74. Fermi GRB 210529B: Global MASTER-Net observations report
  75. GRB 210528A: Fermi GBM detection
  76. GRB 210528A: AstroSat CZTI detection
  77. GRB 210528A: BALROG localization (Fermi Trigger 643903431 / GRB 210528586)
  78. GRB 210528A: Fermi GBM Final Real-time Localization
  79. Fermi GRB 210524B: DDOTI Upper Limits on the Afterglow
  80. Fermi GRB 210519A: Global MASTER-Net observations report
  81. IPN triangulation of GRB 210518A
  82. Fermi trigger No 643065622: Global MASTER-Net observations report
  83. GRB 210518.889: DDOTI Upper Limits on the Afterglow
  84. Fermi trigger No 642991619: Global MASTER-Net observations report
  85. Fermi GRB 210516A: Global MASTER-Net observations report
  86. Fermi GRB 210515B: Global MASTER-Net observations report
  87. Fermi GRB 210515A: Global MASTER-Net observations report
  88. Fermi GRB 210511A: Global MASTER-Net observations report
  89. Fermi GRB 210510A: DDOTI Upper Limits on the Afterglow
  90. Fermi GRB 210510A: Global MASTER-Net observations report
  91. Swift trigger 1047857 is 4U 1700-377
  92. Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
  93. IceCube-210503A: IceCube observation of a high-energy neutrino candidate event
  94. DDOTI Observations of ZTF21aayokph (AT2021lfa)
  95. Swift GRB210504.58: Global MASTER-Net observations report
  96. Fermi GRB 210503A: Global MASTER-Net observations report
  97. Swift GRB210502.74: Global MASTER-Net observations report
  98. Swift Detection of MAXI J1803-298 including an optical counterpart
  99. Fermi GRB 210501A: Global MASTER-Net observations report
  100. GRB 210430A: Swift detection of a burst

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