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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"

43094 results found.

  1. IceCube-250416A - IceCube observation of a high-energy neutrino candidate track-like event
  2. IceCube-250416A: Global MASTER-Net observations report
  3. GRB 250416B: Fermi GBM Final Real-time Localization
  4. GRB 250416A: Fermi GBM Final Real-time Localization
  5. SVOM/sb25041603: SVOM/COLIBRÍ (FM-GFT) Upper Limit on the Optical Counterpart
  6. SVOM/sb25041603: SVOM detection of an X-ray transient
  7. IceCube 250414.324: DDOTI Optical Observations
  8. GRB 250413A: AstroSat CZTI detection
  9. EP250304a: ATCA radio observations
  10. GRB 250412A: AstroSat CZTI detection
  11. EP250404a: Nanshan 0.43m Telescope optical observatios
  12. Fermi trigger No 766148493: Global MASTER-Net observations report
  13. Fermi trigger No 766173972: Global MASTER-Net observations report
  14. GRB 250411A: DDOTI Optical Observations
  15. Fermi GRB 250411A: Global MASTER-Net observations report
  16. GRB 250411A: Fermi GBM Final Real-time Localization
  17. GRB 250407A: Continued KAIT/Nickel optical observations
  18. GRB 250314A: e-MERLIN observations
  19. GRB 250407A: Mondy and AbAO Optical Observations
  20. EP250227a: Further NOT optical observations
  21. GRB 250320B: cubesat Avion detection
  22. IceCube-250406A: Swift-XRT observations
  23. IPN triangulation of GRB 250321D (consistent with the fast X-ray transient EP250321a)
  24. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-250409A
  25. IPN triangulation of GRB 250407A
  26. EP250407a: Global MASTER-Net observations report
  27. GRB 250407A: LCO detection of a fading optical counterpart
  28. Fermi-LAT gamma-ray observations of IceCube-250406A
  29. EP250407a: Swift-XRT observations
  30. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  31. Konus-Wind detection of GRB 250407A
  32. GRB 250407A: SVOM/GRM observation of a bright long burst
  33. GRB 250407A: EP-WXT afterglow detection
  34. EP250407a: EP-WXT detection of a fast X-ray transient
  35. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  36. GRB 250407A: KAIT Optical Afterglow Candidate
  37. IceCube-250406A: No candidates from the Zwicky Transient Facility
  38. GRB 250407A: Fermi GBM Detection
  39. GRB 250407A: Swift-XRT afterglow detection
  40. Fermi GRB 250407A: Global MASTER-Net observations report
  41. GRB 250407A: Swift ToO observations
  42. GRB 250407A: SRG/ART-XC afterglow detection
  43. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  44. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  45. Konus-Wind detection of GRB 250406B (short/hard)
  46. IPN triangulation of GRB 250406B (short/hard)
  47. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  48. GRB 250407A: Fermi GBM Final Real-time Localization
  49. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  51. IceCube 250406.951: DDOTI Optical Observations
  52. GRB 250406A: AstroSat CZTI detection
  53. IceCube Alert 250406.95: Global MASTER-Net observations report
  54. Fermi trigger No 765663719: Global MASTER-Net observations report
  55. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  56. Fermi GRB 250406A: Global MASTER-Net observations report
  57. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  58. GRB 250406A: Fermi GBM Final Real-time Localization
  59. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  60. Fermi trigger No 765619921: Global MASTER-Net observations report
  61. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  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. GRB 250404A / EP250404a: Mondy optical observations
  66. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  67. GRB 250404A / EP250404a: GMG spectroscopic redshift at z ~ 2.627
  68. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  69. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  70. EP250402a: Optical upper limit with PD 1.3m observations
  71. GRB 250404A / EP250404a: NOT optical observations
  72. GRB 250331D: Swift-XRT afterglow detection
  73. GRB 250404B: AstroSat CZTI detection of a short burst
  74. GRB 250403A: AstroSat CZTI detection
  75. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  76. EP250404a: REM optical/NIR observations
  77. EP250404a: Seimei/TriCCS optical counterpart detection
  78. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  79. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  80. EP250404a: LCO optical counterpart detection
  81. Fermi GRB 250404A: Global MASTER-Net observations report
  82. EP250404a: Xinglong decaying optical counterpart
  83. GRB 250403A: Montarrenti Observatory optical detection
  84. GRB 250404A: Fermi GBM Detection
  85. EP250404a: Global MASTER-Net observations report
  86. GRB 250403A: KAIT optical observations
  87. EP250404a: AKO Optical Afterglow Detection
  88. EP250404a: LAST detection of optical counterpart
  89. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  90. EP250404a: Xinglong-2.16m spectroscopic redshift
  91. GRB 250403A: Fermi GBM observations
  92. GRB 250327B: VIRT Optical Upper Limit
  93. EP250404a: Mephisto multi-band optical detection
  94. EP250404a: BOOTES-4/JGT optical afterglow detection
  95. EP250404a: Nanshan/HMT optical counterpart detection
  96. EP250404a: Einstein Probe detection of an X-ray transient
  97. GRB 250404A: Fermi GBM Final Real-time Localization
  98. GRB 250403A: Swift/UVOT Detection
  99. GRB 250402A: Swift/UVOT Upper Limits
  100. EP250402a: Optical upper limit with Kinder observations

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