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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"

39220 results found.

  1. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  2. GRB 260511B: SVOM/VT optical observations
  3. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  4. GRB 260510B: EP-FXT follow-up observation
  5. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  6. GRB 260510C: Fermi GBM Observation
  7. GRB 260509A: SAO RAS optical observations
  8. GRB 260511A: REM near-infrared detection
  9. GRB 260511B: GROWTH-India Telescope optical observations
  10. GRB 260511B: AstroSat CZTI detection
  11. GRB 260506B: Glowbug gamma-ray detection
  12. GRB 260506A: Glowbug gamma-ray detection of a short burst
  13. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  14. GRB 260511B: NuSTAR detection of prompt emission
  15. GRB 260511A: NuSTAR detection of prompt emission
  16. GRB 260511B: Fermi GBM Detection
  17. GRB 260511C: Fermi GBM Final Real-time Localization
  18. GRB 260511B: SVOM/VT optical observation with VHF data
  19. GRB 260511B: TRT optical observation
  20. GRB 260510B: SVOM/ECLAIRs refined analysis
  21. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  22. GRB 260511A: Fermi GBM Detection
  23. GRB 260511B SVOM/C-GFT optical counterpart detection
  24. EP260509a: LCO optical upper limits
  25. GRB 260511A: UTGO H50 optical afterglow observation
  26. GRB 260510C: AstroSat CZTI detection
  27. GRB 260511B: SVOM detection of a burst
  28. GRB 260511B: Fermi GBM Final Real-time Localization
  29. GRB 260510C: EP-FXT follow-up observation
  30. GRB 260510C: SVOM/VT optical counterpart confirmation
  31. GRB 260511A: SVOM/VT optical observation with VHF data
  32. Fermi GRB 260511A: Global MASTER-Net observations report
  33. GRB 260511A: KAIT optical afterglow observations
  34. GRB 260511A: LCO optical afterglow detection
  35. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  36. GRB 260511A: TRT optical counterpart detection
  37. GRB 260511A: SVOM detection of a bright burst
  38. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  39. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  40. GRB 260511A: Fermi GBM Final Real-time Localization
  41. GRB 260510B: SVOM/VT optical upper limits
  42. GRB 260510C: SVOM/VT optical upper limits
  43. GRB 260510C: MAXI/GSC detection
  44. EP260509a: Global MASTER-Net observations report
  45. Fermi GBM Sub-Threshold Detection of GRB 260510B
  46. GRB 260510D: Fermi GBM Final Real-time Localization
  47. GRB 260510B: GOTO early upper limit
  48. GRB 260510C: SVOM detection of a burst
  49. GRB 260510C: Fermi GBM Final Real-time Localization
  50. GRB 260510A: GECAM-B observation
  51. GRB 260510B: LCO optical upper limits
  52. GRB 260509A: Liverpool Telescope optical observations
  53. GRB 260510B: SVOM detection of a burst
  54. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  55. GRB 260509A: LCO optical observations
  56. SVOM GRB 260509A: MASTER-OAFA optical observation
  57. Fermi GRB 260510A: Global MASTER-Net observations report
  58. GRB 260509A: KAIT optical observations
  59. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  60. GRB 260510A: Fermi GBM Final Real-time Localization
  61. GRB 260509A: SVOM/VT optical candidate with VHF data
  62. GRB 260509A: LCO optical counterpart detection
  63. GRB 260509A: GOTO optical counterpart candidate
  64. GRB 260509A: SVOM detection of a burst
  65. GRB 260506B: AstroSat CZTI detection
  66. EP260507a: REM optical/NIR observations
  67. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  68. EP260507a: COLIBRÍ optical observations
  69. GRB 260507A: Fermi GBM Final Real-time Localization
  70. EP260507a: TRT optical counterpart detection
  71. EP260507a: LCO optical counterpart
  72. GRB 260504B: AstroSat CZTI detection
  73. GRB 260504B: SVOM/ECLAIRs refined analysis
  74. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  75. GRB 260506B: Fermi GBM Final Real-time Localization
  76. Fermi GRB 260506A: Global MASTER-Net observations report
  77. GRB 260506A: Fermi GBM Final Real-time Localization
  78. GRB 260503A: GECAM-B observation of a burst
  79. IceCube Alert 260505A: Global MASTER-Net observations report
  80. GRB 260430B: Glowbug gamma-ray detection
  81. GRB 260504B: SVOM/VT optical upper limits
  82. GRB 260421B: radio observation with the VLA
  83. Konus-Wind detection of GRB 260504B (short/hard)
  84. GRB 260504B: GECAM-B detection
  85. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  86. GRB 260504C: SVOM/GRM observation of short GRB
  87. GRB 260504B: SVOM/GRM spectral analysis
  88. GRB 260430B: AstroSat CZTI detection of a long burst
  89. GRB 260504B: SVOM/MXT refined analysis and potential detection
  90. GRB 260504B: EP-FXT upper limit
  91. GRB 260502A: SVOM/GRM observation of a short GRB
  92. GRB 260503A: SVOM/GRM observation of a GRB
  93. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  94. Konus-Wind detection of GRB 260415C
  95. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  96. Konus-Wind detection of GRB 260411C
  97. GRB 260504B: REM optical/NIR observations
  98. IPN triangulation of GRB 260429A
  99. IPN triangulation of GRB 260428A
  100. GRB 260504B: AST3-2 i-band upper limit

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