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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"

26132 results found.

  1. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  2. GRB 260510C: Fermi GBM Observation
  3. GRB 260509A: SAO RAS optical observations
  4. GRB 260511A: REM near-infrared detection
  5. GRB 260511B: GROWTH-India Telescope optical observations
  6. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  7. GRB 260511B: Fermi GBM Detection
  8. GRB 260511C: Fermi GBM Final Real-time Localization
  9. GRB 260511B: SVOM/VT optical observation with VHF data
  10. GRB 260511B: TRT optical observation
  11. GRB 260510B: SVOM/ECLAIRs refined analysis
  12. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  13. GRB 260511A: Fermi GBM Detection
  14. GRB 260511B SVOM/C-GFT optical counterpart detection
  15. GRB 260511A: UTGO H50 optical afterglow observation
  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. EP260509a: EP-FXT non-detection and upper limit
  21. GRB 260511A: SVOM/VT optical observation with VHF data
  22. Fermi GRB 260511A: Global MASTER-Net observations report
  23. GRB 260511A: KAIT optical afterglow observations
  24. GRB 260511A: LCO optical afterglow detection
  25. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  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. EP260509a: Global MASTER-Net observations report
  34. Fermi GBM Sub-Threshold Detection of GRB 260510B
  35. GRB 260510D: Fermi GBM Final Real-time Localization
  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. EP260509a: Einstein Probe detection of an X-ray transient
  41. GRB 260509A: Liverpool Telescope optical observations
  42. GRB 260510B: SVOM detection of a burst
  43. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  44. SVOM GRB 260509A: MASTER-OAFA optical observation
  45. Fermi GRB 260510A: Global MASTER-Net observations report
  46. GRB 260510A: Fermi GBM Final Real-time Localization
  47. GRB 260509A: SVOM/VT optical candidate with VHF data
  48. GRB 260509A: LCO optical counterpart detection
  49. GRB 260509A: GOTO optical counterpart candidate
  50. GRB 260509A: SVOM detection of a burst
  51. EP260507a: REM optical/NIR observations
  52. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  53. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  54. EP260507a: COLIBRÍ optical observations
  55. EP260507a: SVOM/VT optical observations
  56. EP260507a: Liverpool Telescope optical upper limits
  57. GRB 260507A: Fermi GBM Final Real-time Localization
  58. EP260507a: GOTO optical counterpart detection
  59. EP260507a: TRT optical counterpart detection
  60. EP260507a: Kinder optical counterpart candidate
  61. EP260507a: LCO optical counterpart
  62. EP260507a: Einstein Probe detection of an X-ray transient
  63. GRB 260504B: SVOM/ECLAIRs refined analysis
  64. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  65. GRB 260506B: Fermi GBM Final Real-time Localization
  66. EP260502a is likely a flaring star
  67. Fermi GRB 260506A: Global MASTER-Net observations report
  68. GRB 260506A: Fermi GBM Final Real-time Localization
  69. GRB 260503A: GECAM-B observation of a burst
  70. IceCube Alert 260505A: Global MASTER-Net observations report
  71. GRB 260504B: SVOM/VT optical upper limits
  72. GRB 260504B: GECAM-B detection
  73. GRB 260504C: SVOM/GRM observation of short GRB
  74. GRB 260504B: SVOM/GRM spectral analysis
  75. GRB 260504B: SVOM/MXT refined analysis and potential detection
  76. GRB 260504B: EP-FXT upper limit
  77. GRB 260502A: SVOM/GRM observation of a short GRB
  78. GRB 260503A: SVOM/GRM observation of a GRB
  79. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  80. GRB 260504B: REM optical/NIR observations
  81. IPN triangulation of GRB 260429A
  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. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  89. GRB 260502A: GECAM-B observation of a short burst
  90. GRB 260502A: Fermi GBM Final Localization
  91. The EP-WXT trigger 01709261576 is likely a flaring star
  92. GRB 260429B / EP260429a: EP-FXT follow-up observation
  93. EP260502a: BOOTES-7: early optical upper limit
  94. EP260502a: Las Cumbres upper limit
  95. EP260502a: Einstein Probe detection of an X-ray transient
  96. GRB 260429A: SVOM/GRM observation of a short burst
  97. EP260429a: Global MASTER-Net observations report
  98. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  99. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  100. EP260429a: LCO optical upper limits

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