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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').
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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"
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submitter:"Judith Racusin"

21805 results found.

  1. GRB 250424A: Swift/UVOT Detection
  2. Konus-Wind detection of GRB 250424A
  3. GRB 250424A: Skynet Optical Observations
  4. GRB 250424A: Kilonova-Catcher optical afterglow detection
  5. GRB 250407A: GRBAlpha detection
  6. GRB 250404A / EP250404a: GRBAlpha detection
  7. GRB 250330B: GRBAlpha detection
  8. GRB 250419A: SVOM/ECLAIRs refined analysis
  9. GRB 250424A: Enhanced Swift-XRT position
  10. GRB 250424A: COLIBRÍ Detection of a Bright Optical Counterpart
  11. GRB 250424A: BlackGEM optical afterglow detection
  12. GRB 250424A: DDOTI Afterglow Detection
  13. GRB 250424A: REM optical/NIR afterglow detection
  14. GRB 250424A: Swift detection of a burst with an optical counterpart
  15. Swift GRB 250424A: Global MASTER-Net OT detection
  16. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  17. EP250421a: Nickel optical upper limit
  18. SVOM/sb25042207: XRT observations
  19. SVOM/sb25042207: GOTO optical upper limits
  20. GRB 250421A: AstroSat CZTI detection
  21. SVOM/sb25042207: SVOM detection of an X-ray transient
  22. IceCube-250421A: DDOTI Detection of the LAST Candidate
  23. GRB 250419A: Mephisto Multi-band Optical Detection
  24. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  25. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  26. EP250421a: NOT optical observations
  27. GRB 250419A: Optical Observations via Virtual Telescope Project
  28. EP250421a: REM optical upper limit
  29. EP250421A: COLIBRÍ Optical Upper Limit
  30. GRB 250419A: Mondy Continued Optical Observations
  31. EP250421a: Einstein Probe detection of an X-ray transient
  32. EP250421a: Mephisto optical counterpart confirmation
  33. EP250421a: JinShan likely optical counterpart
  34. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  35. GRB 250419A: LCO optical observation
  36. GRB 250419A: JinShan optical observations
  37. GRB 250419A: SVOM/C-GFT optical observations
  38. GRB 250419A: Swift/UVOT Follow up
  39. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  40. GRB 250419A: LCO optical afterglow multi-band observations
  41. GRB 250419A: Mondy and AbAO Optical Observations
  42. GRB 250419A: AKO Optical Afterglow Detection
  43. GRB 250419A: KAIT optical afterglow observations
  44. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  45. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  46. GRB 250419A: SVOM detection of a soft burst
  47. EP20250416a: Swift/XRT counterpart detection
  48. IceCube-250416A: DDOTI Optical Observations
  49. EP250416a: Gemini South-GMOS optical counterpart
  50. SVOM/sb25041603 is not a GRB
  51. EP250416a: Einstein Probe detection of an X-ray transient
  52. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  53. SVOM/sb25041603: SVOM detection of an X-ray transient
  54. IceCube 250414.324: DDOTI Optical Observations
  55. EP250404a: Nanshan 0.43m Telescope optical observatios
  56. GRB 250411A: DDOTI Optical Observations
  57. GRB 250314A: e-MERLIN observations
  58. GRB 250407A: Mondy and AbAO Optical Observations
  59. EP250227a: Further NOT optical observations
  60. GRB 250320B: cubesat Avion detection
  61. IceCube-250406A: Swift-XRT observations
  62. EP250407a: Global MASTER-Net observations report
  63. GRB 250407A: LCO detection of a fading optical counterpart
  64. GRB 250407A: SVOM/GRM observation of a bright long burst
  65. GRB 250407A: EP-WXT afterglow detection
  66. EP250407a: EP-WXT detection of a fast X-ray transient
  67. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  68. GRB 250407A: KAIT Optical Afterglow Candidate
  69. IceCube-250406A: No candidates from the Zwicky Transient Facility
  70. GRB 250407A: Swift-XRT afterglow detection
  71. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  72. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  73. Konus-Wind detection of GRB 250406B (short/hard)
  74. IPN triangulation of GRB 250406B (short/hard)
  75. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  76. IceCube 250406.951: DDOTI Optical Observations
  77. GRB 250406A: AstroSat CZTI detection
  78. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  79. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  80. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  81. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  82. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  83. Konus-Wind detection of GRB 250404A / EP250404a
  84. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  85. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  86. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  87. EP250402a: Optical upper limit with PD 1.3m observations
  88. GRB 250404A / EP250404a: NOT optical observations
  89. GRB 250331D: Swift-XRT afterglow detection
  90. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  91. EP250404a: REM optical/NIR observations
  92. EP250404a: Seimei/TriCCS optical counterpart detection
  93. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  94. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  95. EP250404a: LCO optical counterpart detection
  96. EP250404a: Xinglong decaying optical counterpart
  97. GRB 250403A: Montarrenti Observatory optical detection
  98. GRB 250403A: KAIT optical observations
  99. EP250404a: AKO Optical Afterglow Detection
  100. EP250404a: LAST detection of optical counterpart

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