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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"

32495 results found.

  1. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  2. GRB 260510B: EP-FXT follow-up observation
  3. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  4. GRB 260510C: Fermi GBM Observation
  5. GRB 260509A: SAO RAS optical observations
  6. GRB 260511A: REM near-infrared detection
  7. GRB 260511B: GROWTH-India Telescope optical observations
  8. GRB 260511B: AstroSat CZTI detection
  9. GRB 260506B: Glowbug gamma-ray detection
  10. GRB 260506A: Glowbug gamma-ray detection of a short burst
  11. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  12. GRB 260511B: NuSTAR detection of prompt emission
  13. GRB 260511A: NuSTAR detection of prompt emission
  14. GRB 260511B: Fermi GBM Detection
  15. GRB 260511B: SVOM/VT optical observation with VHF data
  16. GRB 260511B: TRT optical observation
  17. GRB 260510B: SVOM/ECLAIRs refined analysis
  18. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  19. GRB 260511A: Fermi GBM Detection
  20. GRB 260511B SVOM/C-GFT optical counterpart detection
  21. EP260509a: LCO optical upper limits
  22. GRB 260511A: UTGO H50 optical afterglow observation
  23. GRB 260510C: AstroSat CZTI detection
  24. GRB 260511B: SVOM detection of a burst
  25. GRB 260510C: EP-FXT follow-up observation
  26. GRB 260510C: SVOM/VT optical counterpart confirmation
  27. EP260509a: EP-FXT non-detection and upper limit
  28. GRB 260511A: SVOM/VT optical observation with VHF data
  29. Fermi GRB 260511A: Global MASTER-Net observations report
  30. GRB 260511A: KAIT optical afterglow observations
  31. GRB 260511A: LCO optical afterglow detection
  32. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  33. GRB 260511A: TRT optical counterpart detection
  34. GRB 260511A: SVOM detection of a bright burst
  35. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  36. GRB 260510B: SVOM/VT optical upper limits
  37. GRB 260510C: SVOM/VT optical upper limits
  38. GRB 260510C: MAXI/GSC detection
  39. EP260509a: Global MASTER-Net observations report
  40. Fermi GBM Sub-Threshold Detection of GRB 260510B
  41. GRB 260510B: GOTO early upper limit
  42. GRB 260510C: SVOM detection of a burst
  43. GRB 260510A: GECAM-B observation
  44. GRB 260510B: LCO optical upper limits
  45. GRB 260509A: Liverpool Telescope optical observations
  46. GRB 260510B: SVOM detection of a burst
  47. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  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: GOTO optical counterpart candidate
  56. GRB 260509A: SVOM detection of a burst
  57. GRB 260506B: AstroSat CZTI detection
  58. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  59. EP260507a: REM optical/NIR observations
  60. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  61. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  62. EP260507a: COLIBRÍ optical observations
  63. EP260507a: SVOM/VT optical observations
  64. EP260507a: NOT optical observations
  65. EP260507a: further Liverpool Telescope observations
  66. EP260507a: Liverpool Telescope optical upper limits
  67. EP260507a: GOTO optical counterpart detection
  68. EP260507a: TRT optical counterpart detection
  69. EP260507a: Kinder optical counterpart candidate
  70. EP260507a: LCO optical counterpart
  71. GRB 260504B: AstroSat CZTI detection
  72. GRB 260504B: SVOM/ECLAIRs refined analysis
  73. EP260502a is likely a flaring star
  74. Fermi GRB 260506A: Global MASTER-Net observations report
  75. GRB 260503A: GECAM-B observation of a burst
  76. GRB 260430B: Glowbug gamma-ray detection
  77. GRB 260504B: SVOM/VT optical upper limits
  78. GRB 260421B: radio observation with the VLA
  79. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  80. Konus-Wind detection of GRB 260504B (short/hard)
  81. GRB 260504B: GECAM-B detection
  82. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  83. GRB 260504B: SVOM/GRM spectral analysis
  84. GRB 260504B: SVOM/MXT refined analysis and potential detection
  85. GRB 260504B: EP-FXT upper limit
  86. GRB 260502A: SVOM/GRM observation of a short GRB
  87. GRB 260503A: SVOM/GRM observation of a GRB
  88. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  90. GRB 260504B: REM optical/NIR observations
  91. IPN triangulation of GRB 260429A
  92. IPN triangulation of GRB 260428A
  93. GRB 260504B: AST3-2 i-band upper limit
  94. GRB 260504B: LCO z-band upper limit
  95. SVOM GRB 260504B: MASTER-OAFA optical observations
  96. Fermi GRB 260504A: Global MASTER-Net observations report
  97. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  98. GRB 260502A: GECAM-B observation of a short burst
  99. IPN triangulation of a bright burst from SGR 1E1841-045
  100. GRB 260429B / EP260429a: EP-FXT follow-up observation

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