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"

27015 results found.

  1. GRB 251105A: Fermi GBM Final Real-time Localization
  2. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  3. GRB 251103B: Fermi GBM observation
  4. GRB 251104A: SVOM detection of a burst
  5. EP251102a: FTW optical and NIR observations
  6. GRB 251103A: WFST optical observations
  7. EP251102a: update of EP-FXT follow-up observation
  8. GRB 251103A: Xinglong 2.16m optical detection
  9. GRB 251103B: Nanshan/HMT optical upper limit
  10. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  11. GRB 251103B: MITSuME Akeno optical upper limits
  12. GRB 251103B: Swift-XRT refined Analysis
  13. Fermi GRB 251103A: Global MASTER-Net observations report
  14. EP251102a: NIR observations with WINTER
  15. GRB 251103A: J-band detection with WINTER
  16. Swift GRB 251103B: Global MASTER-Net observations report
  17. GRB 251103B: GROWTH-India Telescope optical upper limits
  18. GRB 251103A: Kilonova-Catcher optical afterglow detection
  19. GRB 251103B: Swift detection of a burst
  20. GRB 251103B: Fermi GBM Final Real-time Localization
  21. GRB 251103A: Swift/UVOT Detection
  22. GRB 251103A: Fermi GBM Observation
  23. GRB 251103A: SVOM/GRM observation
  24. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  25. EP251102a: Einstein Probe detection of a fast X-ray transient
  26. EP251102a (WXT 11900459650): LCO observations confirm COLIBRÍ candidate
  27. GRB 251103A: LCO optical observation
  28. EP251102.890: COLIBRÍ optical counterpart candidate
  29. GRB 251103A: GOTO optical afterglow detection
  30. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  31. GRB 251103A: BOOTES-2/TELMA optical afterglow
  32. GRB 251103A: LCO optical afterglow detection
  33. GRB 251103A: Fermi GBM Final Localization
  34. GRB 251103A: NOT optical afterglow candidate
  35. GRB 251103A: SVOM detection of a bright burst
  36. GRB 251102B: Fermi GBM Final Real-time Localization
  37. Fermi GRB 251102A: Global MASTER-Net observations report
  38. GRB 251102A: Fermi GBM Final Real-time Localization
  39. GRB 251031A: Fermi GBM Observation
  40. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  41. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  42. GRB 251031A: Fermi GBM Final Real-time Localization
  43. GRB 251025C: SVOM/GRM observation
  44. GRB 251028A: GECAM-B detection
  45. GRB 251028A: SVOM/GRM observation
  46. GRB 251028A: Fermi GBM Observation
  47. GRB 251026B: LBT near-infrared observations
  48. GRB 250926A: VZLUSAT-2 detection
  49. GRB 251026B: Fermi GBM Observation
  50. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  51. GRB 251026A/EP251026a: EP-FXT follow-up observation
  52. The EP-WXT trigger 01709247588 is likely a flaring star
  53. GRB 251028B: Fermi/GBM observation
  54. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  55. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  56. Fermi GRB 251028B: Global MASTER-Net observations report
  57. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  58. GRB 251028B: Fermi GBM Final Localization Correction
  59. GRB251026B: PRIME H-band upper limit
  60. GRB251025B: 3.6m DOT Optical Observations
  61. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  62. GRB 251028A: Fermi GBM Final Real-time Localization
  63. The EP-WXT trigger 01709247525 is not a real source
  64. SVOM trigger sb25102702/GRB 251027A is not a GRB
  65. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  66. GRB 251027A: Swift-XRT observations
  67. EP251027.145: COLIBRÍ optical upper limits
  68. GRB 251022A: SVOM/GRM observation
  69. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  70. GRB 251027A: LCO optical upper limit
  71. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  72. GRB 251025B: Kilonova-Catcher optical afterglow detection
  73. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  74. GRB 251027A: SVOM detection of a faint burst
  75. GRB 251026B: Tentative GOTO optical counterpart candidate
  76. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  77. Fermi GRB 251026B: Global MASTER-Net observations report
  78. Fermi GRB 251025C: Global MASTER-Net observations report
  79. GRB 251026A: Swift-XRT observations
  80. GRB 251025B: J-band detection with WINTER
  81. IceCube-251025A: DDOTI Optical Upper Limit
  82. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 251026B: Fermi GBM Final Localization
  84. GRB 251026A: SVOM detection of a long burst
  85. GRB 251025B: SVOM/VT optical bump
  86. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  87. GRB 251023A: SVOM/GRM observation
  88. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  89. GRB 251025C: Fermi GBM Final Real-time Localization
  90. GRB 251025B: GROWTH-India Telescope optical observations
  91. GRB 251024A: Swift/UVOT Upper Limits
  92. GRB 251024A: Swift-BAT refined analysis
  93. IceCube Alert 251025.57: Global MASTER-Net observations report
  94. GRB 251024A: Swift-XRT refined Analysis
  95. GRB 251025A (sb25102501): stellar flare confirmed
  96. GRB 251025B: SVOM/VT optical observations with VHF data
  97. GRB 251025B: SVOM/C-GFT optical counterpart detection
  98. GRB 251025B: SVOM detection of a burst
  99. GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
  100. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit

Advanced

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