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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"

28276 results found.

  1. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  2. SVOM/sb25041603: SVOM detection of an X-ray transient
  3. IceCube 250414.324: DDOTI Optical Observations
  4. GRB 250413A: AstroSat CZTI detection
  5. EP250304a: ATCA radio observations
  6. EP250404a: Nanshan 0.43m Telescope optical observatios
  7. GRB 250411A: DDOTI Optical Observations
  8. Fermi GRB 250411A: Global MASTER-Net observations report
  9. GRB 250407A: Continued KAIT/Nickel optical observations
  10. GRB 250314A: e-MERLIN observations
  11. GRB 250407A: Mondy and AbAO Optical Observations
  12. EP250227a: Further NOT optical observations
  13. GRB 250320B: cubesat Avion detection
  14. IceCube-250406A: Swift-XRT observations
  15. GRB 250407A: LCO detection of a fading optical counterpart
  16. Fermi-LAT gamma-ray observations of IceCube-250406A
  17. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 250407A: SVOM/GRM observation of a bright long burst
  19. GRB 250407A: EP-WXT afterglow detection
  20. EP250407a: EP-WXT detection of a fast X-ray transient
  21. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  22. GRB 250407A: KAIT Optical Afterglow Candidate
  23. IceCube-250406A: No candidates from the Zwicky Transient Facility
  24. GRB 250407A: Fermi GBM Detection
  25. GRB 250407A: Swift-XRT afterglow detection
  26. GRB 250407A: SRG/ART-XC afterglow detection
  27. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  28. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  29. IPN triangulation of GRB 250406B (short/hard)
  30. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  31. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  32. IceCube 250406.951: DDOTI Optical Observations
  33. GRB 250406A: AstroSat CZTI detection
  34. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  35. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  36. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  37. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  38. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  39. Konus-Wind detection of GRB 250404A / EP250404a
  40. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  41. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  42. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  43. EP250402a: Optical upper limit with PD 1.3m observations
  44. GRB 250404A / EP250404a: NOT optical observations
  45. GRB 250331D: Swift-XRT afterglow detection
  46. GRB 250404B: AstroSat CZTI detection of a short burst
  47. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  48. EP250404a: REM optical/NIR observations
  49. EP250404a: Seimei/TriCCS optical counterpart detection
  50. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  51. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  52. EP250404a: LCO optical counterpart detection
  53. EP250404a: Xinglong decaying optical counterpart
  54. GRB 250403A: Montarrenti Observatory optical detection
  55. GRB 250404A: Fermi GBM Detection
  56. GRB 250403A: KAIT optical observations
  57. EP250404a: AKO Optical Afterglow Detection
  58. EP250404a: LAST detection of optical counterpart
  59. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  60. GRB 250403A: Fermi GBM observations
  61. GRB 250327B: VIRT Optical Upper Limit
  62. EP250404a: Mephisto multi-band optical detection
  63. GRB 250331C Swift-BAT refined analysis
  64. GRB 250331B Swift-BAT refined analysis
  65. GRB 250330A Swift-BAT refined analysis
  66. EP250321A: J band upper limit by SYSU 80cm telescope
  67. EP250404a: Nanshan/HMT optical counterpart detection
  68. EP250404a: Einstein Probe detection of an X-ray transient
  69. GRB 250403A: Swift/UVOT Detection
  70. GRB 250402A: Swift/UVOT Upper Limits
  71. EP250402a: Optical upper limit with Kinder observations
  72. GRB 250403A: REM NIR afterglow detection
  73. GRB 250403A: LCO optical counterpart detection
  74. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  75. GRB 250403A: JinShan optical observations
  76. GRB 250403A: Optical counterpart detection by LCO.
  77. EP250402a: EP-FXT follow-up observations
  78. GRB 250403A: Swift-XRT observations
  79. GRB 250322A: 10 GHz VLA radio upper limits
  80. GRB 250403A: GMG Optical Observation
  81. GRB 250403A: 1.6m Mephisto multi-band optical detection
  82. GRB 250402A: Fermi GBM Observation
  83. GRB 250403A: SVOM/C-GFT optical observations
  84. GRB 250402A: Swift-XRT observations
  85. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  86. GRB 250402A: REM optical/NIR upper limits
  87. GRB 250402A: LCO optical counterpart detection
  88. EP250402a: Einstein Probe detection of a fast X-ray transient
  89. GRB 250402B: AstroSat CZTI detection of a short burst
  90. GRB 250402A: SVOM/VT optical counterpart
  91. GRB 250402A: SVOM detection of a burst
  92. GRB 250331C: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  93. GRB 250329B: Swift/UVOT Upper Limit
  94. GRB 250329A: Swift/UVOT Upper Limit
  95. GRB 250327B: Swift/UVOT Detection
  96. GRB 250327A: Swift/UVOT Upper Limits
  97. GRB 250331E: SVOM/GRM observation
  98. GRB 250327B: Kilonova-Catcher Observations
  99. GRB250331D: AbAO optical observations
  100. GRB 250331D: Fermi GBM observation

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