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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32486 results found.

  1. GRB 260506A: Glowbug gamma-ray detection of a short burst
  2. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  3. GRB 260511B: NuSTAR detection of prompt emission
  4. GRB 260511A: NuSTAR detection of prompt emission
  5. GRB 260511B: Fermi GBM Detection
  6. GRB 260511B: SVOM/VT optical observation with VHF data
  7. GRB 260511B: TRT optical observation
  8. GRB 260510B: SVOM/ECLAIRs refined analysis
  9. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  10. GRB 260511A: Fermi GBM Detection
  11. GRB 260511B SVOM/C-GFT optical counterpart detection
  12. EP260509a: LCO optical upper limits
  13. GRB 260511A: UTGO H50 optical afterglow observation
  14. GRB 260510C: AstroSat CZTI detection
  15. GRB 260511B: SVOM detection of a burst
  16. GRB 260510C: EP-FXT follow-up observation
  17. GRB 260510C: SVOM/VT optical counterpart confirmation
  18. EP260509a: EP-FXT non-detection and upper limit
  19. GRB 260511A: SVOM/VT optical observation with VHF data
  20. Fermi GRB 260511A: Global MASTER-Net observations report
  21. GRB 260511A: KAIT optical afterglow observations
  22. GRB 260511A: LCO optical afterglow detection
  23. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  24. GRB 260511A: TRT optical counterpart detection
  25. GRB 260511A: SVOM detection of a bright burst
  26. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  27. GRB 260510B: SVOM/VT optical upper limits
  28. GRB 260510C: SVOM/VT optical upper limits
  29. GRB 260510C: MAXI/GSC detection
  30. EP260509a: Global MASTER-Net observations report
  31. Fermi GBM Sub-Threshold Detection of GRB 260510B
  32. GRB 260510B: GOTO early upper limit
  33. GRB 260510C: SVOM detection of a burst
  34. GRB 260510A: GECAM-B observation
  35. GRB 260510B: LCO optical upper limits
  36. GRB 260509A: Liverpool Telescope optical observations
  37. GRB 260510B: SVOM detection of a burst
  38. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  39. GRB 260509A: LCO optical observations
  40. SVOM GRB 260509A: MASTER-OAFA optical observation
  41. Fermi GRB 260510A: Global MASTER-Net observations report
  42. GRB 260509A: KAIT optical observations
  43. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  44. GRB 260509A: SVOM/VT optical candidate with VHF data
  45. GRB 260509A: LCO optical counterpart detection
  46. GRB 260509A: GOTO optical counterpart candidate
  47. GRB 260509A: SVOM detection of a burst
  48. GRB 260506B: AstroSat CZTI detection
  49. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  50. EP260507a: REM optical/NIR observations
  51. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  52. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  53. EP260507a: COLIBRÍ optical observations
  54. EP260507a: SVOM/VT optical observations
  55. EP260507a: NOT optical observations
  56. EP260507a: further Liverpool Telescope observations
  57. EP260507a: Liverpool Telescope optical upper limits
  58. EP260507a: GOTO optical counterpart detection
  59. EP260507a: TRT optical counterpart detection
  60. EP260507a: Kinder optical counterpart candidate
  61. EP260507a: LCO optical counterpart
  62. GRB 260504B: AstroSat CZTI detection
  63. GRB 260504B: SVOM/ECLAIRs refined analysis
  64. EP260502a is likely a flaring star
  65. Fermi GRB 260506A: Global MASTER-Net observations report
  66. GRB 260503A: GECAM-B observation of a burst
  67. GRB 260430B: Glowbug gamma-ray detection
  68. GRB 260504B: SVOM/VT optical upper limits
  69. GRB 260421B: radio observation with the VLA
  70. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  71. Konus-Wind detection of GRB 260504B (short/hard)
  72. GRB 260504B: GECAM-B detection
  73. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  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. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  80. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  81. GRB 260504B: REM optical/NIR observations
  82. IPN triangulation of GRB 260429A
  83. IPN triangulation of GRB 260428A
  84. GRB 260504B: AST3-2 i-band upper limit
  85. GRB 260504B: LCO z-band upper limit
  86. SVOM GRB 260504B: MASTER-OAFA optical observations
  87. Fermi GRB 260504A: Global MASTER-Net observations report
  88. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  89. GRB 260502A: GECAM-B observation of a short burst
  90. IPN triangulation of a bright burst from SGR 1E1841-045
  91. GRB 260429B / EP260429a: EP-FXT follow-up observation
  92. EP260502a: BOOTES-7 observations of a fading catalogued source close to the X-ray position
  93. GRB 260429B / EP260429a: AstroSat CZTI detection
  94. EP260502a: BOOTES-7: early optical upper limit
  95. EP260502a: Las Cumbres upper limit
  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 260424B: AstroSat CZTI detection
  100. GRB 260429B / EP260429a: COLIBRÍ optical upper limit

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