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"

36223 results found.

  1. GRB 250520A: REM optical/NIR early observations
  2. GRB 250520B: Fermi GBM Final Real-time Localization
  3. GRB 250520A:SVOM/VT optical candidate
  4. GRB 250520A: COLIBRÍ optical upper limit
  5. GRB 250520A: DDOTI Optical Upper Limit
  6. GRB 250520A: AstroSat CZTI detection of a short burst
  7. GRB 250516B: GRBAlpha detection
  8. GRB 250520A: SVOM/GRM observation
  9. GRB 250520A: Enhanced Swift-XRT position
  10. GRB 250520A: GOTO optical upper limit
  11. GRB 250520A: Prompt enhanced Swift-XRT position
  12. GRB 250520A: Swift detection of a burst
  13. Swift GRB 250520A: Global MASTER-Net observations report
  14. GRB 250516B: Insight-HXMT detection
  15. EP250427a/GRB250427A: VLA Detection of Radio Counterpart
  16. GRB 250516A: Swift-BAT refined analysis
  17. GRB 250516A: COLIBRÍ optical upper limit
  18. Konus-Wind detection of GRB 250516A
  19. GRB 250516B: NuSTAR Detection of the Prompt Emission
  20. Fermi GRB 250516A: Global MASTER-Net observations report
  21. GRB 250515A: Swift-XRT observations
  22. GRB 250515A: NOT classification of GOTO25cqo as a type-Ia SN
  23. Fermi Gamma-ray Burst Monitor trigger 769160489/250517320 is not a GRB
  24. GRB 250515A:COLIBRÍ optical observations of the GOTO candidate
  25. Swift GRB 250516A: Global MASTER-Net observations report
  26. GRB 250515A: 1.6m Mephisto optical detection
  27. GRB 250516A: AstroSat CZTI detection
  28. GRB 250515A/GOTO25cqo: SVOM/VT optical blue color
  29. GRB 250516A: Fermi GBM Observation
  30. GRB 250516A: Swift-XRT refined Analysis
  31. GRB 250516A: Swift/UVOT Detection
  32. GRB 250515A: Swift ToO observations
  33. GRB 250516B: GECAM-B detection of a bright long burst
  34. GRB 250516A: Enhanced Swift-XRT position
  35. GRB 250516A: Swift detection of a burst
  36. GRB 250516A: Fermi GBM Final Real-time Localization
  37. GRB 250512B / EP250512a: SVOM/GRM analysis
  38. GRB 250515A: GOTO candidate optical counterpart
  39. GRB 250515A: Fermi GBM Final Localization
  40. GRB 250424A: COLIBRÍ detection of the associated supernova
  41. Konus-Wind detection of GRB 250512B / EP250512a
  42. GRB 250502A: TESS observations
  43. GRB 250511A: GECAM-A detection of a short burst
  44. GRB 250509A: Swift-BAT refined analysis
  45. Fermi GRB 250512A: Global MASTER-Net observations report
  46. Konus-Wind detection of GRB 250506A
  47. EP250512a/GRB 250512B: REM optical/NIR observations
  48. EP250511a: Koshka Zeiss-1000 Optical Upper Limit
  49. GRB 250507B: AstroSat CZTI detection
  50. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  51. EP250512a/GRB 250512B: FTW optical and NIR observations of the counterpart
  52. GRB 250512B/EP250512a: SVOM/VT optical fading
  53. GRB 250512B/EP250512a:SVOM/VT bright optical counterpart
  54. GRB 250507B: GRBAlpha detection
  55. GRB 250506A: GRBAlpha detection
  56. GRB 250512B: SVOM detection of a burst
  57. GRB 250507B: SVOM/GRM observation of a burst
  58. GRB 250512A: Fermi GBM Final Real-time Localization
  59. EP250511a: REM optical/NIR observations
  60. GRB 250510B: Fermi GBM Observation
  61. Fermi GRB 250510C: Global MASTER-Net observations report
  62. Fermi GRB 250510B: Global MASTER-Net observations report
  63. GRB 250510C: Fermi GBM Final Real-time Localization
  64. GRB 250510A: Swift-XRT observations
  65. GRB 250509A: Fermi GBM Observation
  66. GRB 250510A: follow-up observation with EP-FXT
  67. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  68. GRB 250510B: Fermi GBM Final Localization
  69. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  70. GRB 250509A: Swift-XRT refined Analysis
  71. GRB 250510A: SVOM possible detection of a burst
  72. GRB 250507A: J-band observations with WINTER (duplicate submission)
  73. GRB 250507A: J-band observations with WINTER
  74. GRB 250509A: Enhanced Swift-XRT position
  75. GRB 250509A: Prompt enhanced Swift-XRT position
  76. Fermi GRB 250509A: Global MASTER-Net observations report
  77. Swift GRB 250509A: Global MASTER-Net observations report
  78. GRB 250509A: Swift detection of a burst
  79. GRB 250509A: Fermi GBM Final Real-time Localization
  80. GRB 250506A: NOT optical upper limits
  81. EP250508a: KAIT optical upper limit
  82. GRB 250507A: KAIT optical upper limit
  83. GRB 250505B: SVOM/GRM observation of a short burst
  84. GRB 250502A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  85. GRB 250506A: GECAM detection
  86. EP250508a: REM optical/NIR observations
  87. GRB 250506A: Swift-XRT afterglow detection
  88. GRB 250506A: SVOM/VT optical upper limit
  89. GRB 250507A: Swift-XRT refined Analysis
  90. GRB 250506A: Swift/UVOT Upper Limits
  91. GRB 250427B : SVOM detection of a burst through offline search
  92. GRB 250507A: follow-up observation with EP-FXT
  93. GRB 250430A / EP250430a: AstroSat CZTI detection
  94. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 250507A: refined SVOM/MXT data analysis
  96. GRB 250507A: REM optical/NIR observations
  97. GRB 250507A: SVOM/VT optical upper limit
  98. GRB 250506A: Swift-XRT observations
  99. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  100. GRB 250507A: SVOM detection of a long burst

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov