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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.

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

19290 results found.

  1. GRB 260511A: BALROG localization (Fermi Trigger 800172815 / GRB 260511259)
  2. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  3. GRB 260511A: Fermi GBM Final Real-time Localization
  4. GRB 260510B: SVOM/VT optical upper limits
  5. GRB 260510C: SVOM/VT optical upper limits
  6. GRB 260510C: MAXI/GSC detection
  7. EP260509a: Global MASTER-Net observations report
  8. Fermi GBM Sub-Threshold Detection of GRB 260510B
  9. GRB 260510D: Fermi GBM Final Real-time Localization
  10. GRB 260510B: GOTO early upper limit
  11. GRB 260510C: SVOM detection of a burst
  12. GRB 260510C: Fermi GBM Final Real-time Localization
  13. GRB 260510A: GECAM-B observation
  14. GRB 260510B: LCO optical upper limits
  15. EP260509a: Einstein Probe detection of an X-ray transient
  16. GRB 260509A: Liverpool Telescope optical observations
  17. GRB 260510B: SVOM detection of a burst
  18. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  19. GRB 260509A: LCO optical observations
  20. SVOM GRB 260509A: MASTER-OAFA optical observation
  21. Fermi GRB 260510A: Global MASTER-Net observations report
  22. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  23. GRB 260510A: Fermi GBM Final Real-time Localization
  24. GRB 260509A: SVOM/VT optical candidate with VHF data
  25. GRB 260509A: LCO optical counterpart detection
  26. GRB 260509A: GOTO optical counterpart candidate
  27. GRB 260509A: SVOM detection of a burst
  28. GRB 260506B: AstroSat CZTI detection
  29. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  30. EP260507a: REM optical/NIR observations
  31. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  32. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  33. EP260507a: COLIBRÍ optical observations
  34. EP260507a: SVOM/VT optical observations
  35. EP260507a: further Liverpool Telescope observations
  36. EP260507a: Liverpool Telescope optical upper limits
  37. GRB 260507A: Fermi GBM Final Real-time Localization
  38. EP260507a: GOTO optical counterpart detection
  39. EP260507a: TRT optical counterpart detection
  40. EP260507a: Kinder optical counterpart candidate
  41. EP260507a: LCO optical counterpart
  42. EP260507a: Einstein Probe detection of an X-ray transient
  43. GRB 260504B: AstroSat CZTI detection
  44. GRB 260504B: SVOM/ECLAIRs refined analysis
  45. GRB 260506B: BALROG localization (Fermi Trigger 799765648 / GRB 260506547)
  46. GRB 260506B: Fermi GBM Final Real-time Localization
  47. EP260502a is likely a flaring star
  48. Fermi GRB 260506A: Global MASTER-Net observations report
  49. GRB 260506A: Fermi GBM Final Real-time Localization
  50. GRB 260503A: GECAM-B observation of a burst
  51. IceCube Alert 260505A: Global MASTER-Net observations report
  52. GRB 260430B: Glowbug gamma-ray detection
  53. GRB 260504B: SVOM/VT optical upper limits
  54. GRB 260421B: radio observation with the VLA
  55. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  56. GRB 260504B: GECAM-B detection
  57. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  58. GRB 260504C: SVOM/GRM observation of short GRB
  59. GRB 260430B: AstroSat CZTI detection of a long burst
  60. GRB 260504B: SVOM/MXT refined analysis and potential detection
  61. GRB 260504B: EP-FXT upper limit
  62. GRB 260502A: SVOM/GRM observation of a short GRB
  63. GRB 260503A: SVOM/GRM observation of a GRB
  64. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  65. Konus-Wind detection of GRB 260411C
  66. GRB 260504B: REM optical/NIR observations
  67. GRB 260504B: AST3-2 i-band upper limit
  68. GRB 260504B: LCO z-band upper limit
  69. SVOM GRB 260504B: MASTER-OAFA optical observations
  70. GRB 260504B: SVOM detection of a short burst
  71. Fermi GRB 260504A: Global MASTER-Net observations report
  72. GRB 260504A: Fermi GBM Final Real-time Localization
  73. GRB 260503A: Fermi GBM Final Real-time Localization
  74. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  75. GRB 260502A: GECAM-B observation of a short burst
  76. GRB 260502A: Fermi GBM Final Localization
  77. The EP-WXT trigger 01709261576 is likely a flaring star
  78. GRB 260429B / EP260429a: EP-FXT follow-up observation
  79. EP260502a: BOOTES-7 observations of a fading catalogued source close to the X-ray position
  80. GRB 260429B / EP260429a: AstroSat CZTI detection
  81. EP260502a: BOOTES-7: early optical upper limit
  82. EP260502a: Einstein Probe detection of an X-ray transient
  83. GRB 260429A: SVOM/GRM observation of a short burst
  84. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  85. EP260429a: Global MASTER-Net observations report
  86. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  87. GRB 260424B: AstroSat CZTI detection
  88. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  89. EP260429a: LCO optical upper limits
  90. EP260430a: LCO optical upper limits
  91. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  92. GRB 260429A: Fermi GBM Detection
  93. Fermi GRB 260429A: Global MASTER-Net observations report
  94. EP260430a: Global MASTER-Net observations report
  95. EP260430a: Einstein Probe detection of an X-ray transient
  96. EP260429a: EP-WXT detection of a fast X-ray transient
  97. GRB 260429A: Fermi GBM Final Real-time Localization
  98. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  99. GRB 260428A: GECAM-B detection of a possible long duration Type I burst
  100. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube

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