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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"

27920 results found.

  1. EP250416a: Swift/XRT counterpart fading
  2. Konus-Wind detection of GRB 250403A
  3. EP20250416a: Swift/XRT counterpart detection
  4. EP250416a: Gemini South-GMOS optical counterpart
  5. EP250416a: GSP optical upper limit
  6. EP250416a: Einstein Probe detection of an X-ray transient
  7. IceCube-250416A - IceCube observation of a high-energy neutrino candidate track-like event
  8. GRB 250416B: Fermi GBM Final Real-time Localization
  9. GRB 250416A: Fermi GBM Final Real-time Localization
  10. SVOM/sb25041603: SVOM detection of an X-ray transient
  11. GRB 250413A: AstroSat CZTI detection
  12. GRB 250412A: AstroSat CZTI detection
  13. GRB 250411A: Fermi GBM Final Real-time Localization
  14. GRB 250407A: Mondy and AbAO Optical Observations
  15. GRB 250320B: cubesat Avion detection
  16. IceCube-250406A: Swift-XRT observations
  17. IPN triangulation of GRB 250407A
  18. GRB 250407A: LCO detection of a fading optical counterpart
  19. EP250407a: Swift-XRT observations
  20. Konus-Wind detection of GRB 250407A
  21. GRB 250407A: SVOM/GRM observation of a bright long burst
  22. GRB 250407A: EP-WXT afterglow detection
  23. EP250407a: EP-WXT detection of a fast X-ray transient
  24. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  25. GRB 250407A: Fermi GBM Detection
  26. GRB 250407A: Swift-XRT afterglow detection
  27. GRB 250407A: Swift ToO observations
  28. GRB 250407A: SRG/ART-XC afterglow detection
  29. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  30. Konus-Wind detection of GRB 250406B (short/hard)
  31. IPN triangulation of GRB 250406B (short/hard)
  32. GRB 250407A: Fermi GBM Final Real-time Localization
  33. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  35. GRB 250406A: AstroSat CZTI detection
  36. GRB 250406A: Fermi GBM Final Real-time Localization
  37. Konus-Wind detection of GRB 250404A / EP250404a
  38. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  39. GRB 250331D: Swift-XRT afterglow detection
  40. GRB 250404B: AstroSat CZTI detection of a short burst
  41. GRB 250403A: AstroSat CZTI detection
  42. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  43. EP250404a: Seimei/TriCCS optical counterpart detection
  44. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  45. EP250404a: LCO optical counterpart detection
  46. GRB 250403A: Montarrenti Observatory optical detection
  47. GRB 250404A: Fermi GBM Detection
  48. EP250404a: AKO Optical Afterglow Detection
  49. EP250404a: LAST detection of optical counterpart
  50. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  51. EP250404a: Xinglong-2.16m spectroscopic redshift
  52. GRB 250327B: VIRT Optical Upper Limit
  53. EP250404a: Mephisto multi-band optical detection
  54. GRB 250331C Swift-BAT refined analysis
  55. GRB 250331B Swift-BAT refined analysis
  56. GRB 250330A Swift-BAT refined analysis
  57. EP250321A: J band upper limit by SYSU 80cm telescope
  58. EP250404a: BOOTES-4/JGT optical afterglow detection
  59. EP250404a: Nanshan/HMT optical counterpart detection
  60. EP250404a: Einstein Probe detection of an X-ray transient
  61. GRB 250404A: Fermi GBM Final Real-time Localization
  62. GRB 250403A: Swift/UVOT Detection
  63. GRB 250402A: Swift/UVOT Upper Limits
  64. GRB 250403A: REM NIR afterglow detection
  65. GRB 250403A: LCO optical counterpart detection
  66. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  67. GRB 250402A: EP-FXT afterglow detection
  68. GRB 250403A: Optical counterpart detection by LCO.
  69. GRB 250403A: Swift-XRT observations
  70. GRB 250322A: 10 GHz VLA radio upper limits
  71. GRB 250403A: 1.6m Mephisto multi-band optical detection
  72. GRB 250403A: GOTO detection of the optical afterglow
  73. GRB 250402A: Swift-XRT observations
  74. GRB 250403A : SVOM detection of a burst
  75. GRB 250403A: Fermi GBM Final Real-time Localization
  76. GRB 250225B: VLT host galaxy redshift z = 0.950
  77. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  78. GRB 250402A: VLT/FORS2 spectroscopic redshift z = 2.823
  79. GRB 250402A: LCO optical counterpart detection
  80. EP250402a: Einstein Probe detection of a fast X-ray transient
  81. GRB 250402B: AstroSat CZTI detection of a short burst
  82. GRB 250402A: SVOM detection of a burst
  83. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  84. GRB 250314A: ALMA detection
  85. GRB 250329B: Swift/UVOT Upper Limit
  86. GRB 250329A: Swift/UVOT Upper Limit
  87. GRB 250327B: Swift/UVOT Detection
  88. GRB 250327A: Swift/UVOT Upper Limits
  89. GRB250331D: AbAO optical observations
  90. GRB 250331D: Fermi GBM observation
  91. GRB 250331C: Swift/UVOT Upper Limits
  92. GRB 250331B: Swift/UVOT Upper Limits
  93. GRB 250219A: NOT candidate host galaxy detection
  94. GRB 250322B: GRBAlpha detection
  95. GRB 250331D: Swift-XRT observations
  96. GRB 250331C: Swift-XRT refined Analysis
  97. GRB 250331B: Swift-XRT refined Analysis
  98. GRB 250331B: Swift-XRT refined Analysis
  99. GRB 250322B possible detection by the AstroSat Satellite
  100. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Epoch 2)

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