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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"
body:"GRB"
submitter:"Judith Racusin"

28282 results found.

  1. EP20250416a: Swift/XRT counterpart detection
  2. IceCube-250416A: DDOTI Optical Observations
  3. EP250416a: Gemini South-GMOS optical counterpart
  4. SVOM/sb25041603 is not a GRB
  5. EP250416a: GSP optical upper limit
  6. EP250416a: Einstein Probe detection of an X-ray transient
  7. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  8. SVOM/sb25041603: SVOM detection of an X-ray transient
  9. IceCube 250414.324: DDOTI Optical Observations
  10. GRB 250413A: AstroSat CZTI detection
  11. EP250304a: ATCA radio observations
  12. EP250404a: Nanshan 0.43m Telescope optical observatios
  13. GRB 250411A: DDOTI Optical Observations
  14. Fermi GRB 250411A: Global MASTER-Net observations report
  15. GRB 250407A: Continued KAIT/Nickel optical observations
  16. GRB 250314A: e-MERLIN observations
  17. GRB 250407A: Mondy and AbAO Optical Observations
  18. EP250227a: Further NOT optical observations
  19. GRB 250320B: cubesat Avion detection
  20. IceCube-250406A: Swift-XRT observations
  21. GRB 250407A: LCO detection of a fading optical counterpart
  22. Fermi-LAT gamma-ray observations of IceCube-250406A
  23. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  24. GRB 250407A: SVOM/GRM observation of a bright long burst
  25. GRB 250407A: EP-WXT afterglow detection
  26. EP250407a: EP-WXT detection of a fast X-ray transient
  27. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  28. GRB 250407A: KAIT Optical Afterglow Candidate
  29. IceCube-250406A: No candidates from the Zwicky Transient Facility
  30. GRB 250407A: Fermi GBM Detection
  31. GRB 250407A: Swift-XRT afterglow detection
  32. GRB 250407A: SRG/ART-XC afterglow detection
  33. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  34. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  35. IPN triangulation of GRB 250406B (short/hard)
  36. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  37. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  38. IceCube 250406.951: DDOTI Optical Observations
  39. GRB 250406A: AstroSat CZTI detection
  40. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  41. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  42. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  43. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  44. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  45. Konus-Wind detection of GRB 250404A / EP250404a
  46. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  47. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  48. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  49. EP250402a: Optical upper limit with PD 1.3m observations
  50. GRB 250404A / EP250404a: NOT optical observations
  51. GRB 250331D: Swift-XRT afterglow detection
  52. GRB 250404B: AstroSat CZTI detection of a short burst
  53. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  54. EP250404a: REM optical/NIR observations
  55. EP250404a: Seimei/TriCCS optical counterpart detection
  56. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  57. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  58. EP250404a: LCO optical counterpart detection
  59. EP250404a: Xinglong decaying optical counterpart
  60. GRB 250403A: Montarrenti Observatory optical detection
  61. GRB 250404A: Fermi GBM Detection
  62. GRB 250403A: KAIT optical observations
  63. EP250404a: AKO Optical Afterglow Detection
  64. EP250404a: LAST detection of optical counterpart
  65. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  66. GRB 250403A: Fermi GBM observations
  67. GRB 250327B: VIRT Optical Upper Limit
  68. EP250404a: Mephisto multi-band optical detection
  69. GRB 250331C Swift-BAT refined analysis
  70. GRB 250331B Swift-BAT refined analysis
  71. GRB 250330A Swift-BAT refined analysis
  72. EP250321A: J band upper limit by SYSU 80cm telescope
  73. EP250404a: Nanshan/HMT optical counterpart detection
  74. EP250404a: Einstein Probe detection of an X-ray transient
  75. GRB 250403A: Swift/UVOT Detection
  76. GRB 250402A: Swift/UVOT Upper Limits
  77. EP250402a: Optical upper limit with Kinder observations
  78. GRB 250403A: REM NIR afterglow detection
  79. GRB 250403A: LCO optical counterpart detection
  80. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  81. GRB 250403A: JinShan optical observations
  82. GRB 250403A: Optical counterpart detection by LCO.
  83. EP250402a: EP-FXT follow-up observations
  84. GRB 250403A: Swift-XRT observations
  85. GRB 250322A: 10 GHz VLA radio upper limits
  86. GRB 250403A: GMG Optical Observation
  87. GRB 250403A: 1.6m Mephisto multi-band optical detection
  88. GRB 250402A: Fermi GBM Observation
  89. GRB 250403A: SVOM/C-GFT optical observations
  90. GRB 250402A: Swift-XRT observations
  91. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  92. GRB 250402A: REM optical/NIR upper limits
  93. GRB 250402A: LCO optical counterpart detection
  94. EP250402a: Einstein Probe detection of a fast X-ray transient
  95. GRB 250402B: AstroSat CZTI detection of a short burst
  96. GRB 250402A: SVOM/VT optical counterpart
  97. GRB 250402A: SVOM detection of a burst
  98. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  99. GRB 250329B: Swift/UVOT Upper Limit
  100. GRB 250329A: Swift/UVOT Upper Limit

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