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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"

28288 results found.

  1. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  2. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  3. GRB 250419A: SVOM detection of a soft burst
  4. EP250416a: Swift/XRT counterpart fading
  5. EP20250416a: Swift/XRT counterpart detection
  6. IceCube-250416A: DDOTI Optical Observations
  7. EP250416a: Gemini South-GMOS optical counterpart
  8. SVOM/sb25041603 is not a GRB
  9. EP250416a: GSP optical upper limit
  10. EP250416a: Einstein Probe detection of an X-ray transient
  11. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  12. SVOM/sb25041603: SVOM detection of an X-ray transient
  13. IceCube 250414.324: DDOTI Optical Observations
  14. GRB 250413A: AstroSat CZTI detection
  15. EP250304a: ATCA radio observations
  16. EP250404a: Nanshan 0.43m Telescope optical observatios
  17. GRB 250411A: DDOTI Optical Observations
  18. Fermi GRB 250411A: Global MASTER-Net observations report
  19. GRB 250407A: Continued KAIT/Nickel optical observations
  20. GRB 250314A: e-MERLIN observations
  21. GRB 250407A: Mondy and AbAO Optical Observations
  22. EP250227a: Further NOT optical observations
  23. GRB 250320B: cubesat Avion detection
  24. IceCube-250406A: Swift-XRT observations
  25. GRB 250407A: LCO detection of a fading optical counterpart
  26. Fermi-LAT gamma-ray observations of IceCube-250406A
  27. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  28. GRB 250407A: SVOM/GRM observation of a bright long burst
  29. GRB 250407A: EP-WXT afterglow detection
  30. EP250407a: EP-WXT detection of a fast X-ray transient
  31. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  32. GRB 250407A: KAIT Optical Afterglow Candidate
  33. IceCube-250406A: No candidates from the Zwicky Transient Facility
  34. GRB 250407A: Fermi GBM Detection
  35. GRB 250407A: Swift-XRT afterglow detection
  36. GRB 250407A: SRG/ART-XC afterglow detection
  37. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  38. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  39. IPN triangulation of GRB 250406B (short/hard)
  40. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  41. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  42. IceCube 250406.951: DDOTI Optical Observations
  43. GRB 250406A: AstroSat CZTI detection
  44. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  45. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  46. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  47. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  48. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  49. Konus-Wind detection of GRB 250404A / EP250404a
  50. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  51. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  52. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  53. EP250402a: Optical upper limit with PD 1.3m observations
  54. GRB 250404A / EP250404a: NOT optical observations
  55. GRB 250331D: Swift-XRT afterglow detection
  56. GRB 250404B: AstroSat CZTI detection of a short burst
  57. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  58. EP250404a: REM optical/NIR observations
  59. EP250404a: Seimei/TriCCS optical counterpart detection
  60. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  61. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  62. EP250404a: LCO optical counterpart detection
  63. EP250404a: Xinglong decaying optical counterpart
  64. GRB 250403A: Montarrenti Observatory optical detection
  65. GRB 250404A: Fermi GBM Detection
  66. GRB 250403A: KAIT optical observations
  67. EP250404a: AKO Optical Afterglow Detection
  68. EP250404a: LAST detection of optical counterpart
  69. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  70. GRB 250403A: Fermi GBM observations
  71. GRB 250327B: VIRT Optical Upper Limit
  72. EP250404a: Mephisto multi-band optical detection
  73. GRB 250331C Swift-BAT refined analysis
  74. GRB 250331B Swift-BAT refined analysis
  75. GRB 250330A Swift-BAT refined analysis
  76. EP250321A: J band upper limit by SYSU 80cm telescope
  77. EP250404a: Nanshan/HMT optical counterpart detection
  78. EP250404a: Einstein Probe detection of an X-ray transient
  79. GRB 250403A: Swift/UVOT Detection
  80. GRB 250402A: Swift/UVOT Upper Limits
  81. EP250402a: Optical upper limit with Kinder observations
  82. GRB 250403A: REM NIR afterglow detection
  83. GRB 250403A: LCO optical counterpart detection
  84. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  85. GRB 250403A: JinShan optical observations
  86. GRB 250403A: Optical counterpart detection by LCO.
  87. EP250402a: EP-FXT follow-up observations
  88. GRB 250403A: Swift-XRT observations
  89. GRB 250322A: 10 GHz VLA radio upper limits
  90. GRB 250403A: GMG Optical Observation
  91. GRB 250403A: 1.6m Mephisto multi-band optical detection
  92. GRB 250402A: Fermi GBM Observation
  93. GRB 250403A: SVOM/C-GFT optical observations
  94. GRB 250402A: Swift-XRT observations
  95. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  96. GRB 250402A: REM optical/NIR upper limits
  97. GRB 250402A: LCO optical counterpart detection
  98. EP250402a: Einstein Probe detection of a fast X-ray transient
  99. GRB 250402B: AstroSat CZTI detection of a short burst
  100. GRB 250402A: SVOM/VT optical counterpart

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