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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"

28097 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 260511B: LCO optical observations
  7. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  8. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  9. GRB 260510B: EP-FXT follow-up observation
  10. GRB 260510C: Fermi GBM Observation
  11. GRB 260509A: SAO RAS optical observations
  12. GRB 260511A: REM near-infrared detection
  13. GRB 260511B: GROWTH-India Telescope optical observations
  14. GRB 260506B: Glowbug gamma-ray detection
  15. GRB 260506A: Glowbug gamma-ray detection of a short burst
  16. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  17. GRB 260511B: NuSTAR detection of prompt emission
  18. GRB 260511A: NuSTAR detection of prompt emission
  19. GRB 260511B: Fermi GBM Detection
  20. GRB 260511B: SVOM/VT optical observation with VHF data
  21. GRB 260511B: TRT optical observation
  22. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  23. GRB 260511A: Fermi GBM Detection
  24. GRB 260511B SVOM/C-GFT optical counterpart detection
  25. EP260509a: LCO optical upper limits
  26. GRB 260511A: UTGO H50 optical afterglow observation
  27. GRB 260511B: SVOM detection of a burst
  28. GRB 260510C: EP-FXT follow-up observation
  29. EP260509a: EP-FXT non-detection and upper limit
  30. GRB 260511A: SVOM/VT optical observation with VHF data
  31. Fermi GRB 260511A: Global MASTER-Net observations report
  32. GRB 260511A: KAIT optical afterglow observations
  33. GRB 260511A: LCO optical afterglow detection
  34. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  35. GRB 260511A: TRT optical counterpart detection
  36. GRB 260511A: SVOM detection of a bright burst
  37. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  38. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  39. GRB 260510C: MAXI/GSC detection
  40. EP260509a: Global MASTER-Net observations report
  41. Fermi GBM Sub-Threshold Detection of GRB 260510B
  42. GRB 260510C: SVOM detection of a burst
  43. GRB 260510B: LCO optical upper limits
  44. EP260509a: Einstein Probe detection of an X-ray transient
  45. GRB 260509A: Liverpool Telescope optical observations
  46. GRB 260510B: SVOM detection of a burst
  47. GRB 260509A: LCO optical observations
  48. SVOM GRB 260509A: MASTER-OAFA optical observation
  49. Fermi GRB 260510A: Global MASTER-Net observations report
  50. GRB 260509A: KAIT optical observations
  51. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  52. GRB 260509A: SVOM/VT optical candidate with VHF data
  53. GRB 260509A: LCO optical counterpart detection
  54. GRB 260509A: SVOM detection of a burst
  55. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  56. EP260507a: REM optical/NIR observations
  57. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  58. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  59. EP260507a: COLIBRÍ optical observations
  60. EP260507a: NOT optical observations
  61. EP260507a: further Liverpool Telescope observations
  62. EP260507a: Liverpool Telescope optical upper limits
  63. EP260507a: TRT optical counterpart detection
  64. EP260507a: Kinder optical counterpart candidate
  65. EP260507a: LCO optical counterpart
  66. EP260507a: Einstein Probe detection of an X-ray transient
  67. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  68. Fermi GRB 260506A: Global MASTER-Net observations report
  69. IceCube Alert 260505A: Global MASTER-Net observations report
  70. GRB 260430B: Glowbug gamma-ray detection
  71. GRB 260421B: radio observation with the VLA
  72. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  73. GRB 260430B: AstroSat CZTI detection of a long burst
  74. GRB 260502A: SVOM/GRM observation of a short GRB
  75. GRB 260503A: SVOM/GRM observation of a GRB
  76. Konus-Wind detection of GRB 260411C
  77. GRB 260504B: REM optical/NIR observations
  78. GRB 260504B: LCO z-band upper limit
  79. SVOM GRB 260504B: MASTER-OAFA optical observations
  80. GRB 260504B: SVOM detection of a short burst
  81. Fermi GRB 260504A: Global MASTER-Net observations report
  82. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  83. GRB 260429B / EP260429a: EP-FXT follow-up observation
  84. EP260502a: Einstein Probe detection of an X-ray transient
  85. GRB 260429A: SVOM/GRM observation of a short burst
  86. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  87. EP260429a: Global MASTER-Net observations report
  88. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  89. GRB 260424B: AstroSat CZTI detection
  90. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  91. EP260429a: LCO optical upper limits
  92. EP260430a: LCO optical upper limits
  93. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  94. GRB 260429A: Fermi GBM Detection
  95. Fermi GRB 260429A: Global MASTER-Net observations report
  96. EP260430a: Global MASTER-Net observations report
  97. EP260430a: Einstein Probe detection of an X-ray transient
  98. EP260429a: EP-WXT detection of a fast X-ray transient
  99. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  100. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube

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