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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"

42572 results found.

  1. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  2. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-250409A
  3. IPN triangulation of GRB 250407A
  4. EP250407a: Global MASTER-Net observations report
  5. GRB 250407A: LCO detection of a fading optical counterpart
  6. Fermi-LAT gamma-ray observations of IceCube-250406A
  7. EP250407a: Swift-XRT observations
  8. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  9. Konus-Wind detection of GRB 250407A
  10. GRB 250407A: SVOM/GRM observation of a bright long burst
  11. GRB 250407A: EP-WXT afterglow detection
  12. EP250407a: EP-WXT detection of a fast X-ray transient
  13. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  14. GRB 250407A: KAIT Optical Afterglow Candidate
  15. IceCube-250406A: No candidates from the Zwicky Transient Facility
  16. GRB 250407A: Fermi GBM Detection
  17. GRB 250407A: Swift-XRT afterglow detection
  18. Fermi GRB 250407A: Global MASTER-Net observations report
  19. GRB 250407A: Swift ToO observations
  20. GRB 250407A: SRG/ART-XC afterglow detection
  21. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  22. Konus-Wind detection of GRB 250406B (short/hard)
  23. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  24. GRB 250407A: Fermi GBM Final Real-time Localization
  25. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  26. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  27. IceCube 250406.951: DDOTI Optical Observations
  28. GRB 250406A: AstroSat CZTI detection
  29. IceCube Alert 250406.95: Global MASTER-Net observations report
  30. Fermi trigger No 765663719: Global MASTER-Net observations report
  31. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  32. Fermi GRB 250406A: Global MASTER-Net observations report
  33. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  34. GRB 250406A: Fermi GBM Final Real-time Localization
  35. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  36. Fermi trigger No 765619921: Global MASTER-Net observations report
  37. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  38. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit
  39. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  40. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  41. Konus-Wind detection of GRB 250404A / EP250404a
  42. GRB 250404A / EP250404a: Mondy optical observations
  43. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  44. GRB 250404A / EP250404a: GMG spectroscopic redshift at z ~ 2.627
  45. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  46. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  47. EP250402a: Optical upper limit with PD 1.3m observations
  48. GRB 250404A / EP250404a: NOT optical observations
  49. GRB 250331D: Swift-XRT afterglow detection
  50. GRB 250404B: AstroSat CZTI detection of a short burst
  51. GRB 250403A: AstroSat CZTI detection
  52. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  53. EP250404a: REM optical/NIR observations
  54. EP250404a: Seimei/TriCCS optical counterpart detection
  55. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  56. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  57. EP250404a: LCO optical counterpart detection
  58. Fermi GRB 250404A: Global MASTER-Net observations report
  59. EP250404a: Xinglong decaying optical counterpart
  60. GRB 250403A: Montarrenti Observatory optical detection
  61. GRB 250404A: Fermi GBM Detection
  62. EP250404a: Global MASTER-Net observations report
  63. GRB 250403A: KAIT optical observations
  64. EP250404a: AKO Optical Afterglow Detection
  65. EP250404a: LAST detection of optical counterpart
  66. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  67. EP250404a: Xinglong-2.16m spectroscopic redshift
  68. GRB 250403A: Fermi GBM observations
  69. GRB 250327B: VIRT Optical Upper Limit
  70. EP250404a: Mephisto multi-band optical detection
  71. GRB 250331C Swift-BAT refined analysis
  72. GRB 250331B Swift-BAT refined analysis
  73. GRB 250330A Swift-BAT refined analysis
  74. EP250321A: J band upper limit by SYSU 80cm telescope
  75. EP250404a: BOOTES-4/JGT optical afterglow detection
  76. EP250404a: Nanshan/HMT optical counterpart detection
  77. EP250404a: Einstein Probe detection of an X-ray transient
  78. GRB 250404A: Fermi GBM Final Real-time Localization
  79. GRB 250402A: Mondy optical observations
  80. GRB 250403A: Swift/UVOT Detection
  81. GRB 250402A: Swift/UVOT Upper Limits
  82. EP250402a: Optical upper limit with Kinder observations
  83. GRB 250403A: SVOM/VT optical observation
  84. GRB 250403A: REM NIR afterglow detection
  85. GRB 250403A: LCO optical counterpart detection
  86. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  87. GRB 250403A: JinShan optical observations
  88. GRB 250402A: EP-FXT afterglow detection
  89. GRB 250403A: Optical counterpart detection by LCO.
  90. EP250402a: EP-FXT follow-up observations
  91. GRB 250403A: Swift-XRT observations
  92. GRB 250322A: 10 GHz VLA radio upper limits
  93. Fermi GRB 250403A: Global MASTER-Net observations report
  94. GRB 250403A: GOTO optical counterpart follow-up observations
  95. GRB 250402A: NUTTelA-TAO Early Optical Limits
  96. GRB 250403A: GMG Optical Observation
  97. GRB 250403A: 1.6m Mephisto multi-band optical detection
  98. GRB 250402A: Fermi GBM Observation
  99. GRB 250403A: SVOM/C-GFT optical observations
  100. GRB 250403A: GOTO detection of the optical afterglow

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