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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"

11627 results found.

  1. GRB 260127A: COLIBRÍ optical observations
  2. GRB 260127A: NOT optical observations
  3. GRB 260127B: Swift ToO observations
  4. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  5. GRB 260127B: GOTO candidate optical counterpart
  6. GRB 260127A: SVOM/C-GFT optical observations
  7. Fermi GRB 260127B: Global MASTER-Net observations report
  8. GRB 260127B: Fermi GBM Final Real-time Localization
  9. GRB 260127A: LCO optical afterglow discovery
  10. GRB 260127A: Fermi GBM Final Real-time Localization
  11. GRB 260125A: Swift-XRT observations
  12. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  13. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  14. Konus-Wind detection of GRB 260120B
  15. GRB 260125A: Swift ToO observations
  16. GRB 260125A: GOTO candidate optical counterpart
  17. Fermi GRB 260125B: Global MASTER-Net observations report
  18. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 260125B: Fermi GBM Final Real-time Localization
  20. GRB 260125A: Fermi GBM Final Real-time Localization
  21. GRB 260114A: SVOM/VT optical upper limits
  22. GRB 260120A: AstroSat CZTI detection
  23. GRB 260120B: SVOM/GRM observation
  24. GRB 260120A: GECAM-B observation
  25. GRB 260120B: AstroSat CZTI detection
  26. GRB 260114A: Insight-HXMT/HE detection
  27. GRB 260122A: Fermi GBM Final Real-time Localization
  28. Fermi GRB 260120C: Global MASTER-Net observations report
  29. GRB 260120B: Fermi GBM Observation
  30. GRB 260120B: COLIBRÍ optical upper limits
  31. GRB 260120B: SVOM/C-GFT optical counterpart detection
  32. GRB 260120C: Fermi GBM Final Real-time Localization
  33. GRB 260101A: 239Alferov CubeSat detection
  34. GRB 260120B: Fermi GBM Final Real-time Localization
  35. Fermi trigger No 790601190: Global MASTER-Net observations report
  36. Fermi trigger No 790570272: Global MASTER-Net observations report
  37. GRB 251202A: further radio observations with the VLA
  38. GRB 260120A: Fermi GBM Final Real-time Localization
  39. GRB 260115A: AstroSat CZTI detection
  40. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  41. GRB 260115A: GECAM-B observation
  42. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  43. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  44. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  45. Fermi GRB 260115A: Global MASTER-Net observations report
  46. GRB 260115A: Fermi GBM Final Real-time Localization
  47. GRB260114A: STEP/T80S optical limits
  48. GRB 251222A: radio detection with the VLA
  49. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  50. Konus-Wind detection of GRB 260114A
  51. GRB 260114A: 6 GHz VLA observations
  52. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  53. GRB 260114A : MITSuME Akeno optical upper limits
  54. GRB 260114A: COLIBRÍ optical upper limits
  55. GRB 260114A: TNG NIR upper limit
  56. GRB 260114A: NOT optical observations
  57. GRB 260114A: SVOM/GRM observation of a short burst
  58. GRB 260114A: GECAM-B observation of a short burst
  59. GRB 260114A: Mondy optical observations
  60. GRB 260114A: Fermi GBM observation
  61. GRB 260112B: GECAM-B observation
  62. GRB 260114A: GMG Optical Observation
  63. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  64. GRB 260114A: Fermi GBM Final Real-time Localization
  65. Konus-Wind detection of GRB 260101A
  66. GRB 260111A: Swift-XRT observations
  67. GRB 260111A: COLIBRÍ optical afterglow candidate
  68. GRB 260111A: GECAM-B observation of a burst
  69. GRB 260111A: Fermi GBM Observation
  70. GRB 260111A: GOTO optical upper limits
  71. GRB 260112B: Fermi GBM Final Real-time Localization
  72. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  73. GRB 260112A: Fermi GBM Final Real-time Localization
  74. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  75. Fermi GRB 260111A: Global MASTER-Net observations report
  76. GRB 260111A: Fermi GBM Final Real-time Localization
  77. EP260105b / GRB 260105C : Fermi-GBM Sub-Threshold Detection
  78. GRB 260109B: Fermi GBM Final Real-time Localization
  79. GRB 260109A: Fermi GBM Final Real-time Localization
  80. Fermi GRB 260107A: Global MASTER-Net observations report
  81. GRB 260107A: Fermi GBM Final Real-time Localization
  82. Fermi GRB 260105A: Global MASTER-Net observations report
  83. GRB 260105B: Fermi GBM Detection
  84. GRB 260105B: BALROG localization (Fermi Trigger 789348101 / GRB 260105973)
  85. GRB 260105A: SVOM/GRM observation
  86. GRB 260105B: SVOM/GRM observation
  87. Fermi GRB 260105B: Global MASTER-Net observations report
  88. GRB 260105B: Fermi GBM Final Real-time Localization
  89. GRB 260105A: Fermi GBM Final Real-time Localization
  90. GRB 260101A: COLIBRÍ optical upper limits
  91. GRB 260104C: Fermi GBM Final Real-time Localization
  92. Fermi GRB 260104B: Global MASTER-Net observations report
  93. GRB 260104B: Fermi GBM Final Localization
  94. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  95. GRB 260101A: COLIBRÍ optical observations
  96. GRB 260102B: Fermi GBM Final Real-time Localization
  97. Fermi GBM Sub-Threshold Detection of GRB 260102A
  98. Fermi Gamma-ray Burst Monitor trigger 789047602/260102495 is not a GRB
  99. GRB 260101A: Fermi GBM Observation
  100. GRB 260101A: GECAM-B detection

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