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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"

28294 results found.

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

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