Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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"

26922 results found.

  1. Fermi GRB 251217A: Global MASTER-Net observations report
  2. GRB 251217A: Fermi GBM Final Real-time Localization
  3. GRB 251215A: Swift/UVOT Upper LImits
  4. GRB 251215A: Fermi GBM Observation
  5. Fermi GRB 251216A: Global MASTER-Net observations report
  6. GRB 251215A: COLIBRÍ optical upper limit
  7. GRB 251216A: Fermi GBM Final Real-time Localization
  8. EP251214b: KAIT optical upper limit
  9. Fermi GRB 251215A: Global MASTER-Net observations report
  10. EP251214a: Optical upper limit with Kinder observations
  11. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  12. GRB 251215A: Glowbug gamma-ray detection
  13. GRB 251214B: UAFO optical upper limit
  14. GRB 251213A: GRID-10B observation
  15. GRB 251214B: Swift-BAT refined analysis
  16. EP251214b: Global MASTER-Net observations report
  17. EP251214b : Einstein Probe detection of a fast X-ray transient
  18. EP251214b : Einstein Probe detection of a fast X-ray transient
  19. GRB 251214B: AbAO optical observations
  20. GRB 251209A: GECAM-B observation of a long burst
  21. GRB 251214D: GECAM-B observation of a long burst
  22. GRB 251214B: Fermi GBM Observation
  23. EP251214b (EP trigger 01709250023): LCO optical limits
  24. GRID detection of GRB 251213A
  25. GRB 251203B: AbAO optical observations
  26. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  27. GRB 251214B: GECAM-B observation of a long burst
  28. GRB 251214B: Swift-XRT refined Analysis
  29. GRB 251213A: SVOM/GRM observation
  30. GRB 251213A: GECAM-B detection
  31. GRB 251214B: Swift/UVOT Detection
  32. GRB 251215A: Fermi GBM Final Real-time Localization
  33. GRB 251214B: COLIBRÍ observations of the afterglow
  34. EP251214a: EP-FXT non-detection and upper limit
  35. GRB 251214A: GECAM-B observation of a likely long burst
  36. GRB 251214B: 1.3m DFOT optical detection
  37. EP251214a: Global MASTER-Net observations report
  38. GRB 251214B: Xinglong-2.16m optical observation
  39. GRB 251214C: Fermi GBM Final Localization
  40. Fermi trigger No 787396657: Global MASTER-Net observations report
  41. GRB 251214B: SVOM/C-GFT optical observations
  42. EP251214a: COLIBRÍ optical upper limit
  43. Swift GRB 251214B: Global MASTER-Net observations report
  44. EP251214.305: COLIBRÍ optical upper limit
  45. GRB 251214B: Swift detection of a burst with an optical counterpart
  46. GRB 251214B: Fermi GBM Final Real-time Localization
  47. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  48. Fermi GRB 251214A: Global MASTER-Net observations report
  49. GRB 251214A: Fermi GBM Final Real-time Localization
  50. EP251212a: Global MASTER-Net observations report
  51. EP251212a / GRB 251212A: AstroSat CZTI detection
  52. EP251212a: EP-FXT follow-up observation
  53. GRB 251209A: NuSTAR detection of prompt emission
  54. EP251212a : COLIBRÍ optical upper limit
  55. EP251212a: Einstein Probe detection of an X-ray transient
  56. Fermi GRB 251211B: Global MASTER-Net observations report
  57. GRB 251211B: Fermi GBM Final Real-time Localization
  58. IceCube-251210A: DDOTI Optical Upper Limit
  59. SVOM GRB251211.12: Global MASTER-Net observations report
  60. GRB 251211A: Fermi GBM Final Real-time Localization
  61. GRB 251209A: Fermi GBM observation
  62. GRB 251205A: 1.3m DFOT optical upper limit
  63. IceCube Alert 251210.46: Global MASTER-Net observations report
  64. EP251130a: Mondy and AbAO optical observations
  65. Fermi GBM Sub-Threshold Detection of GRB 251205A
  66. GRB 251208B: COLIBRÍ optical upper limits
  67. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  68. GRB 251208C: GECAM-B observation of a short burst
  69. GRB 251208A: GECAM-B observation of a short burst
  70. Fermi GRB 251209A: Global MASTER-Net observations report
  71. Fermi GRB 251208C: Global MASTER-Net observations report
  72. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  73. GRB 251209A: Fermi GBM Final Real-time Localization
  74. GRB 251208B: Fermi GBM Observation
  75. GRB 251208B: GROWTH-India Telescope optical upper limits
  76. GRB 251205A: J-band detection with WINTER
  77. GRB 251208D: Swift-XRT observations
  78. GRB 251208A: SVOM/GRM observation of a short burst
  79. GRB 251208C: SVOM/GRM observation of a short burst
  80. LAT GRB251208.43: Global MASTER-Net observations report
  81. GRB 251205A: Liverpool Telescope further optical follow-up observations
  82. GRB 251208D: LCO optical upper limits
  83. SVOM GRB251208D: Global MASTER-Net observations report
  84. GRB 251208B: Fermi-LAT detection
  85. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  86. GRB 251208D: SVOM possible detection of a faint burst
  87. GRB 251206A: SVOM detection of a burst through offline search
  88. GRB 251208C: Fermi GBM Final Real-time Localization
  89. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  90. GRB 251208B: Fermi GBM Final Real-time Localization
  91. GRB 251208A: Fermi GBM Final Real-time Localization
  92. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  93. GRB 251205A: Liverpool Telescope further optical follow-up observations
  94. SVOM GRB251206.86: Global MASTER-Net observations report
  95. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  96. The EP-WXT trigger 01709249380 is likely a flaring star
  97. GRB 251205A: GROWTH-India Telescope optical observations
  98. GRB 251205A: Swift-BAT refined analysis
  99. GRB 251205A: Swift-XRT refined Analysis
  100. GRB 251205A: Swift/UVOT Detection

Advanced

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