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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"

32706 results found.

  1. GRB 260511B: FRAM-ORM optical detection
  2. GRB 260511A: EP-FXT follow-up observation
  3. GRB 260511B: EP-FXT follow-up observation
  4. GRB 260511B: LCO optical counterpart detection
  5. GRB260511B: MAO/AZT-22 optical observations
  6. GRB 260511A: SVOM/VT optical observations
  7. GRB 260511B: LCO optical observations
  8. GRB 260511B: OHP/T193 spectroscopic observations
  9. GRB 260511B: GOTO optical counterpart detection
  10. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  11. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  12. GRB 260511B: SVOM/VT optical observations
  13. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  14. GRB 260510B: EP-FXT follow-up observation
  15. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  16. GRB 260510C: Fermi GBM Observation
  17. GRB 260509A: SAO RAS optical observations
  18. GRB 260511A: REM near-infrared detection
  19. GRB 260511B: GROWTH-India Telescope optical observations
  20. GRB 260511B: AstroSat CZTI detection
  21. GRB 260506B: Glowbug gamma-ray detection
  22. GRB 260506A: Glowbug gamma-ray detection of a short burst
  23. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  24. GRB 260511B: NuSTAR detection of prompt emission
  25. GRB 260511A: NuSTAR detection of prompt emission
  26. GRB 260511B: Fermi GBM Detection
  27. GRB 260511B: SVOM/VT optical observation with VHF data
  28. GRB 260511B: TRT optical observation
  29. GRB 260510B: SVOM/ECLAIRs refined analysis
  30. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  31. GRB 260511A: Fermi GBM Detection
  32. GRB 260511B SVOM/C-GFT optical counterpart detection
  33. EP260509a: LCO optical upper limits
  34. GRB 260511A: UTGO H50 optical afterglow observation
  35. GRB 260510C: AstroSat CZTI detection
  36. GRB 260511B: SVOM detection of a burst
  37. GRB 260510C: EP-FXT follow-up observation
  38. GRB 260510C: SVOM/VT optical counterpart confirmation
  39. EP260509a: EP-FXT non-detection and upper limit
  40. GRB 260511A: SVOM/VT optical observation with VHF data
  41. Fermi GRB 260511A: Global MASTER-Net observations report
  42. GRB 260511A: KAIT optical afterglow observations
  43. GRB 260511A: LCO optical afterglow detection
  44. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  45. GRB 260511A: TRT optical counterpart detection
  46. GRB 260511A: SVOM detection of a bright burst
  47. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  48. GRB 260510B: SVOM/VT optical upper limits
  49. GRB 260510C: SVOM/VT optical upper limits
  50. GRB 260510C: MAXI/GSC detection
  51. EP260509a: Global MASTER-Net observations report
  52. Fermi GBM Sub-Threshold Detection of GRB 260510B
  53. GRB 260510B: GOTO early upper limit
  54. GRB 260510C: SVOM detection of a burst
  55. GRB 260510A: GECAM-B observation
  56. GRB 260510B: LCO optical upper limits
  57. GRB 260509A: Liverpool Telescope optical observations
  58. GRB 260510B: SVOM detection of a burst
  59. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  60. GRB 260509A: LCO optical observations
  61. SVOM GRB 260509A: MASTER-OAFA optical observation
  62. Fermi GRB 260510A: Global MASTER-Net observations report
  63. GRB 260509A: KAIT optical observations
  64. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  65. GRB 260509A: SVOM/VT optical candidate with VHF data
  66. GRB 260509A: LCO optical counterpart detection
  67. GRB 260509A: GOTO optical counterpart candidate
  68. GRB 260509A: SVOM detection of a burst
  69. GRB 260506B: AstroSat CZTI detection
  70. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  71. EP260507a: REM optical/NIR observations
  72. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  73. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  74. EP260507a: COLIBRÍ optical observations
  75. EP260507a: SVOM/VT optical observations
  76. EP260507a: NOT optical observations
  77. EP260507a: further Liverpool Telescope observations
  78. EP260507a: Liverpool Telescope optical upper limits
  79. EP260507a: GOTO optical counterpart detection
  80. EP260507a: TRT optical counterpart detection
  81. EP260507a: Kinder optical counterpart candidate
  82. EP260507a: LCO optical counterpart
  83. GRB 260504B: AstroSat CZTI detection
  84. GRB 260504B: SVOM/ECLAIRs refined analysis
  85. EP260502a is likely a flaring star
  86. Fermi GRB 260506A: Global MASTER-Net observations report
  87. GRB 260503A: GECAM-B observation of a burst
  88. GRB 260430B: Glowbug gamma-ray detection
  89. GRB 260504B: SVOM/VT optical upper limits
  90. GRB 260421B: radio observation with the VLA
  91. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  92. Konus-Wind detection of GRB 260504B (short/hard)
  93. GRB 260504B: GECAM-B detection
  94. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  95. GRB 260504B: SVOM/GRM spectral analysis
  96. GRB 260504B: SVOM/MXT refined analysis and potential detection
  97. GRB 260504B: EP-FXT upper limit
  98. GRB 260502A: SVOM/GRM observation of a short GRB
  99. GRB 260503A: SVOM/GRM observation of a GRB
  100. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event

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