Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. 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"

28221 results found.

  1. EP260110a: TRT optical upper limits
  2. Konus-Wind detection of GRB 260101A
  3. GRB 260111A: Swift-XRT observations
  4. Swift Trigger 1439093: is probably not GRB 260113A
  5. GRB 260111A: COLIBRÍ optical afterglow candidate
  6. Swift Trigger 1434591 is not a GRB
  7. GRB 260112B: Fermi GBM Final Real-time Localization
  8. GRB 260111A: Swift ToO observations
  9. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  10. GRB 260112A: Fermi GBM Final Real-time Localization
  11. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 260111A: Fermi GBM Final Real-time Localization
  13. Swift trigger 1436759 is not an astrophysical event
  14. EP260110a: BOOTES-5/JGU optical upper limit
  15. EP260110a: Einstein Probe detection of an X-ray transient
  16. GRB 260109C: LCO optical upper limits
  17. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  18. Swift Trigger 1434591: possible GRB 260109C
  19. GRB 260109B: Fermi GBM Final Real-time Localization
  20. GRB 260102A: Swift-XRT afterglow detection
  21. GRB 260109A: Fermi GBM Final Real-time Localization
  22. Swift GRB 251230A: Global MASTER-Net OT detection
  23. GRB 260107A: Fermi GBM Final Real-time Localization
  24. EP260105b/EP-WXT trigger 01709251028: Einstein Probe detection of an X-ray transient
  25. GRB 260105B: Fermi GBM Detection
  26. EP260105a: FTW optical observations
  27. EP260104a: FTW optical observations
  28. GRB 260105B: Fermi GBM Final Real-time Localization
  29. GRB 260105A: Fermi GBM Final Real-time Localization
  30. FRB 20251229A: A potentially hyperactive repeating fast radio burst source
  31. EP260104a: Einstein Probe detection of a fast X-ray transient
  32. GRB 260101A: COLIBRÍ optical upper limits
  33. EP260105a: Einstein Probe detection of an X-ray transient
  34. GRB 260103A: Insight-HXMT/HE detection
  35. GRB 260104A: COLIBRÍ optical upper limits
  36. GRB 260104C: Fermi GBM Final Real-time Localization
  37. GRB 260104A: Swift-XRT refined Analysis
  38. GRB 260104A: Enhanced Swift-XRT position
  39. GRB 260101A: Swift/UVOT Detection
  40. GRB 260104B: Fermi GBM Final Localization
  41. GRB 260104A: Swift detection of a burst
  42. GRB 260101A: COLIBRÍ optical observations
  43. GRB 260102B: Fermi GBM Final Real-time Localization
  44. Fermi GBM Sub-Threshold Detection of GRB 260102A
  45. GRB 260102A: LCO optical upper limits
  46. GRB 260102A: Swift-XRT observations
  47. GRB 251230A / EP251230a: GECAM-B detection
  48. GRB 260102A: SVOM/VT optical counterpart
  49. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  50. GRB 260102A: Swift ToO observations
  51. GRB 260102A: SVOM detection of a burst
  52. GRB 260101A: GECAM-B detection
  53. GRB 260101A: NOT spectroscopic observations
  54. GRB 260101A: SVOM/GRM observation
  55. GRB 260101A: Swift-XRT refined Analysis
  56. GRB 260101A: Enhanced Swift-XRT position
  57. EP260101a: Einstein Probe detection of an X-ray transient
  58. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  59. GRB 260101A: LCO detection of the optical counterpart
  60. GRB 260101A: Swift detection of a burst with an optical counterpart
  61. GRB 260101A: Fermi GBM Final Real-time Localization
  62. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  63. GRB 251230A: GRANDMA/TAROT Early Detection
  64. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  65. EP251229a: Optical upper limit with Kinder observations
  66. GRB 251230A: 1.3m DFOT optical upper limit
  67. GRB 251230A: Swift-XRT refined Analysis
  68. GRB 251231A: Fermi GBM Final Real-time Localization
  69. GRB 251230A: Swift/UVOT detection
  70. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  71. EP251229a: BOOTES-2 early optical upper limit
  72. GRB 251230A: Enhanced Swift-XRT position
  73. GRB 251230A: Early optical counterpart detection by LCO.
  74. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  75. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  76. EP251229a: Einstein Probe detection of an X-ray transient
  77. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  78. GRB 251226A: Glowbug gamma-ray detection
  79. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  80. GRB 251228A: Fermi GBM Final Real-time Localization
  81. GRB 251226A: GECAM-B detection
  82. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  83. GRB 251222A/EP251222b: Optical detection with Kinder observations
  84. EP251222a: Optical upper limit with Kinder observations
  85. GRB 251205A: Kilonova-Catcher optical afterglow detection
  86. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  87. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  88. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  89. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  90. GRB 251222A: Continued 1.3m DFOT optical observation
  91. EP251220a: 3.6m DOT optical afterglow detection
  92. GRB 251222A: Fermi GBM Observation
  93. Konus-Wind detection of GRB 251222A / EP251222b
  94. GRB 251222A: Swift-XRT afterglow detection
  95. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  96. GRB 251222A / EP251222b: GOTO optical counterpart detection
  97. GRB 251222A: 1.3m DFOT optical detection
  98. GRB251221A: 7DT optical upper limits
  99. EP251222a: GSP Optical Counterpart Detection
  100. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171

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