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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"

28096 results found.

  1. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  2. GRB 260511B: FRAM-ORM optical detection
  3. GRB 260511A: EP-FXT follow-up observation
  4. GRB 260511B: EP-FXT follow-up observation
  5. GRB 260511B: LCO optical counterpart detection
  6. GRB260511B: MAO/AZT-22 optical observations
  7. GRB 260511B: LCO optical observations
  8. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  9. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  10. GRB 260510B: EP-FXT follow-up observation
  11. GRB 260510C: Fermi GBM Observation
  12. GRB 260509A: SAO RAS optical observations
  13. GRB 260511A: REM near-infrared detection
  14. GRB 260511B: GROWTH-India Telescope optical observations
  15. GRB 260506B: Glowbug gamma-ray detection
  16. GRB 260506A: Glowbug gamma-ray detection of a short burst
  17. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  18. GRB 260511B: NuSTAR detection of prompt emission
  19. GRB 260511A: NuSTAR detection of prompt emission
  20. GRB 260511B: Fermi GBM Detection
  21. GRB 260511B: SVOM/VT optical observation with VHF data
  22. GRB 260511B: TRT optical observation
  23. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  24. GRB 260511A: Fermi GBM Detection
  25. GRB 260511B SVOM/C-GFT optical counterpart detection
  26. EP260509a: LCO optical upper limits
  27. GRB 260511A: UTGO H50 optical afterglow observation
  28. GRB 260511B: SVOM detection of a burst
  29. GRB 260510C: EP-FXT follow-up observation
  30. EP260509a: EP-FXT non-detection and upper limit
  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 260510C: MAXI/GSC detection
  41. EP260509a: Global MASTER-Net observations report
  42. Fermi GBM Sub-Threshold Detection of GRB 260510B
  43. GRB 260510C: SVOM detection of a burst
  44. GRB 260510B: LCO optical upper limits
  45. EP260509a: Einstein Probe detection of an X-ray transient
  46. GRB 260509A: Liverpool Telescope optical observations
  47. GRB 260510B: SVOM detection of a burst
  48. GRB 260509A: LCO optical observations
  49. SVOM GRB 260509A: MASTER-OAFA optical observation
  50. Fermi GRB 260510A: Global MASTER-Net observations report
  51. GRB 260509A: KAIT optical observations
  52. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  53. GRB 260509A: SVOM/VT optical candidate with VHF data
  54. GRB 260509A: LCO optical counterpart detection
  55. GRB 260509A: SVOM detection of a burst
  56. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  57. EP260507a: REM optical/NIR observations
  58. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  59. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  60. EP260507a: COLIBRÍ optical observations
  61. EP260507a: NOT optical observations
  62. EP260507a: further Liverpool Telescope observations
  63. EP260507a: Liverpool Telescope optical upper limits
  64. EP260507a: TRT optical counterpart detection
  65. EP260507a: Kinder optical counterpart candidate
  66. EP260507a: LCO optical counterpart
  67. EP260507a: Einstein Probe detection of an X-ray transient
  68. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  69. Fermi GRB 260506A: Global MASTER-Net observations report
  70. IceCube Alert 260505A: Global MASTER-Net observations report
  71. GRB 260430B: Glowbug gamma-ray detection
  72. GRB 260421B: radio observation with the VLA
  73. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  74. GRB 260430B: AstroSat CZTI detection of a long burst
  75. GRB 260502A: SVOM/GRM observation of a short GRB
  76. GRB 260503A: SVOM/GRM observation of a GRB
  77. Konus-Wind detection of GRB 260411C
  78. GRB 260504B: REM optical/NIR observations
  79. GRB 260504B: LCO z-band upper limit
  80. SVOM GRB 260504B: MASTER-OAFA optical observations
  81. GRB 260504B: SVOM detection of a short burst
  82. Fermi GRB 260504A: Global MASTER-Net observations report
  83. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  84. GRB 260429B / EP260429a: EP-FXT follow-up observation
  85. EP260502a: Einstein Probe detection of an X-ray transient
  86. GRB 260429A: SVOM/GRM observation of a short burst
  87. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  88. EP260429a: Global MASTER-Net observations report
  89. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  90. GRB 260424B: AstroSat CZTI detection
  91. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  92. EP260429a: LCO optical upper limits
  93. EP260430a: LCO optical upper limits
  94. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  95. GRB 260429A: Fermi GBM Detection
  96. Fermi GRB 260429A: Global MASTER-Net observations report
  97. EP260430a: Global MASTER-Net observations report
  98. EP260430a: Einstein Probe detection of an X-ray transient
  99. EP260429a: EP-WXT detection of a fast X-ray transient
  100. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission

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