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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"

28301 results found.

  1. EP250421a: Mephisto optical counterpart confirmation
  2. IceCube-Cascade 250414A: Upper limits from a search for additional neutrino events in IceCube
  3. EP250421a: JinShan likely optical counterpart
  4. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  5. GRB 250419A: LCO optical observation
  6. GRB 250419A: JinShan optical observations
  7. GRB 250419A: SVOM/C-GFT optical observations
  8. GRB 250419A: Swift/UVOT Follow up
  9. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  10. GRB 250419A: LCO optical afterglow multi-band observations
  11. GRB 250419A: Mondy and AbAO Optical Observations
  12. GRB 250419A: AKO Optical Afterglow Detection
  13. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  14. GRB 250419A: Swift-XRT refined Analysis
  15. GRB 250419A: KAIT optical afterglow observations
  16. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  17. GRB 250419A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart
  18. GRB 250419A: SVOM detection of a soft burst
  19. EP250416a: Swift/XRT counterpart fading
  20. EP20250416a: Swift/XRT counterpart detection
  21. IceCube-250416A: DDOTI Optical Observations
  22. EP250416a: Gemini South-GMOS optical counterpart
  23. SVOM/sb25041603 is not a GRB
  24. EP250416a: GSP optical upper limit
  25. EP250416a: Einstein Probe detection of an X-ray transient
  26. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  27. SVOM/sb25041603: SVOM detection of an X-ray transient
  28. IceCube 250414.324: DDOTI Optical Observations
  29. GRB 250413A: AstroSat CZTI detection
  30. EP250304a: ATCA radio observations
  31. EP250404a: Nanshan 0.43m Telescope optical observatios
  32. GRB 250411A: DDOTI Optical Observations
  33. Fermi GRB 250411A: Global MASTER-Net observations report
  34. GRB 250407A: Continued KAIT/Nickel optical observations
  35. GRB 250314A: e-MERLIN observations
  36. GRB 250407A: Mondy and AbAO Optical Observations
  37. EP250227a: Further NOT optical observations
  38. GRB 250320B: cubesat Avion detection
  39. IceCube-250406A: Swift-XRT observations
  40. GRB 250407A: LCO detection of a fading optical counterpart
  41. Fermi-LAT gamma-ray observations of IceCube-250406A
  42. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 250407A: SVOM/GRM observation of a bright long burst
  44. GRB 250407A: EP-WXT afterglow detection
  45. EP250407a: EP-WXT detection of a fast X-ray transient
  46. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  47. GRB 250407A: KAIT Optical Afterglow Candidate
  48. IceCube-250406A: No candidates from the Zwicky Transient Facility
  49. GRB 250407A: Fermi GBM Detection
  50. GRB 250407A: Swift-XRT afterglow detection
  51. GRB 250407A: SRG/ART-XC afterglow detection
  52. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  53. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  54. IPN triangulation of GRB 250406B (short/hard)
  55. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  56. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  57. IceCube 250406.951: DDOTI Optical Observations
  58. GRB 250406A: AstroSat CZTI detection
  59. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  60. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  61. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  62. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  63. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  64. Konus-Wind detection of GRB 250404A / EP250404a
  65. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  66. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  67. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  68. EP250402a: Optical upper limit with PD 1.3m observations
  69. GRB 250404A / EP250404a: NOT optical observations
  70. GRB 250331D: Swift-XRT afterglow detection
  71. GRB 250404B: AstroSat CZTI detection of a short burst
  72. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  73. EP250404a: REM optical/NIR observations
  74. EP250404a: Seimei/TriCCS optical counterpart detection
  75. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  76. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  77. EP250404a: LCO optical counterpart detection
  78. EP250404a: Xinglong decaying optical counterpart
  79. GRB 250403A: Montarrenti Observatory optical detection
  80. GRB 250404A: Fermi GBM Detection
  81. GRB 250403A: KAIT optical observations
  82. EP250404a: AKO Optical Afterglow Detection
  83. EP250404a: LAST detection of optical counterpart
  84. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  85. GRB 250403A: Fermi GBM observations
  86. GRB 250327B: VIRT Optical Upper Limit
  87. EP250404a: Mephisto multi-band optical detection
  88. GRB 250331C Swift-BAT refined analysis
  89. GRB 250331B Swift-BAT refined analysis
  90. GRB 250330A Swift-BAT refined analysis
  91. EP250321A: J band upper limit by SYSU 80cm telescope
  92. EP250404a: Nanshan/HMT optical counterpart detection
  93. EP250404a: Einstein Probe detection of an X-ray transient
  94. GRB 250403A: Swift/UVOT Detection
  95. GRB 250402A: Swift/UVOT Upper Limits
  96. EP250402a: Optical upper limit with Kinder observations
  97. GRB 250403A: REM NIR afterglow detection
  98. GRB 250403A: LCO optical counterpart detection
  99. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  100. GRB 250403A: JinShan optical observations

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