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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"

36109 results found.

  1. GRB 260506B: Glowbug gamma-ray detection
  2. GRB 260506A: Glowbug gamma-ray detection of a short burst
  3. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  4. GRB 260511B: NuSTAR detection of prompt emission
  5. GRB 260511A: NuSTAR detection of prompt emission
  6. GRB 260511B: Fermi GBM Detection
  7. GRB 260511C: Fermi GBM Final Real-time Localization
  8. GRB 260511B: SVOM/VT optical observation with VHF data
  9. GRB 260511B: TRT optical observation
  10. GRB 260510B: SVOM/ECLAIRs refined analysis
  11. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  12. GRB 260511A: Fermi GBM Detection
  13. GRB 260511B SVOM/C-GFT optical counterpart detection
  14. GRB 260511A: UTGO H50 optical afterglow observation
  15. GRB 260510C: AstroSat CZTI detection
  16. GRB 260511B: SVOM detection of a burst
  17. GRB 260511B: Fermi GBM Final Real-time Localization
  18. GRB 260510C: EP-FXT follow-up observation
  19. GRB 260510C: SVOM/VT optical counterpart confirmation
  20. GRB 260511A: SVOM/VT optical observation with VHF data
  21. Fermi GRB 260511A: Global MASTER-Net observations report
  22. GRB 260511A: KAIT optical afterglow observations
  23. GRB 260511A: LCO optical afterglow detection
  24. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  25. GRB 260511A: TRT optical counterpart detection
  26. GRB 260511A: SVOM detection of a bright burst
  27. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  28. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  29. GRB 260511A: Fermi GBM Final Real-time Localization
  30. GRB 260510B: SVOM/VT optical upper limits
  31. GRB 260510C: SVOM/VT optical upper limits
  32. GRB 260510C: MAXI/GSC detection
  33. Fermi GBM Sub-Threshold Detection of GRB 260510B
  34. GRB 260510D: Fermi GBM Final Real-time Localization
  35. GRB 260510B: GOTO early upper limit
  36. GRB 260510C: SVOM detection of a burst
  37. GRB 260510C: Fermi GBM Final Real-time Localization
  38. GRB 260510A: GECAM-B observation
  39. GRB 260510B: LCO optical upper limits
  40. GRB 260509A: Liverpool Telescope optical observations
  41. GRB 260510B: SVOM detection of a burst
  42. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  43. GRB 260509A: LCO optical observations
  44. SVOM GRB 260509A: MASTER-OAFA optical observation
  45. Fermi GRB 260510A: Global MASTER-Net observations report
  46. GRB 260509A: KAIT optical observations
  47. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  48. GRB 260510A: Fermi GBM Final Real-time Localization
  49. GRB 260509A: SVOM/VT optical candidate with VHF data
  50. GRB 260509A: LCO optical counterpart detection
  51. GRB 260509A: GOTO optical counterpart candidate
  52. GRB 260509A: SVOM detection of a burst
  53. GRB 260506B: AstroSat CZTI detection
  54. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  55. GRB 260507A: Fermi GBM Final Real-time Localization
  56. GRB 260504B: AstroSat CZTI detection
  57. GRB 260504B: SVOM/ECLAIRs refined analysis
  58. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  59. GRB 260506B: Fermi GBM Final Real-time Localization
  60. Fermi GRB 260506A: Global MASTER-Net observations report
  61. GRB 260506A: Fermi GBM Final Real-time Localization
  62. GRB 260503A: GECAM-B observation of a burst
  63. GRB 260430B: Glowbug gamma-ray detection
  64. GRB 260504B: SVOM/VT optical upper limits
  65. GRB 260421B: radio observation with the VLA
  66. Konus-Wind detection of GRB 260504B (short/hard)
  67. GRB 260504B: GECAM-B detection
  68. GRB 260504C: SVOM/GRM observation of short GRB
  69. GRB 260504B: SVOM/GRM spectral analysis
  70. GRB 260430B: AstroSat CZTI detection of a long burst
  71. GRB 260504B: SVOM/MXT refined analysis and potential detection
  72. GRB 260504B: EP-FXT upper limit
  73. GRB 260502A: SVOM/GRM observation of a short GRB
  74. GRB 260503A: SVOM/GRM observation of a GRB
  75. Konus-Wind detection of GRB 260415C
  76. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  77. Konus-Wind detection of GRB 260411C
  78. GRB 260504B: REM optical/NIR observations
  79. IPN triangulation of GRB 260429A
  80. IPN triangulation of GRB 260428A
  81. GRB 260504B: AST3-2 i-band upper limit
  82. GRB 260504B: LCO z-band upper limit
  83. SVOM GRB 260504B: MASTER-OAFA optical observations
  84. GRB 260504B: SVOM detection of a short burst
  85. Fermi GRB 260504A: Global MASTER-Net observations report
  86. GRB 260504A: Fermi GBM Final Real-time Localization
  87. GRB 260503A: Fermi GBM Final Real-time Localization
  88. GRB 260502A: GECAM-B observation of a short burst
  89. GRB 260502A: Fermi GBM Final Localization
  90. GRB 260429B / EP260429a: EP-FXT follow-up observation
  91. GRB 260429B / EP260429a: AstroSat CZTI detection
  92. GRB 260429A: SVOM/GRM observation of a short burst
  93. GRB 260424B: AstroSat CZTI detection
  94. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  95. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  96. GRB 260429A: Fermi GBM Detection
  97. Fermi GRB 260429A: Global MASTER-Net observations report
  98. GRB 260429A: Fermi GBM Final Real-time Localization
  99. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  100. GRB 260428A: GECAM-B detection of a possible long duration Type I burst

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