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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"
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submitter:"Judith Racusin"

43933 results found.

  1. Fermi-LAT gamma-ray observations of IceCube-250406A
  2. EP250407a: Swift-XRT observations
  3. IceCube-250406A: Upper limits from a search for additional neutrino events in IceCube
  4. Konus-Wind detection of GRB 250407A
  5. GRB 250407A: SVOM/GRM observation of a bright long burst
  6. GRB 250407A: EP-WXT afterglow detection
  7. EP250407a: EP-WXT detection of a fast X-ray transient
  8. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  9. GRB 250407A: KAIT Optical Afterglow Candidate
  10. IceCube-250406A: No candidates from the Zwicky Transient Facility
  11. GRB 250407A: Fermi GBM Detection
  12. GRB 250407A: Swift-XRT afterglow detection
  13. Fermi GRB 250407A: Global MASTER-Net observations report
  14. GRB 250407A: Swift ToO observations
  15. GRB 250407A: SRG/ART-XC afterglow detection
  16. LIGO/Virgo/KAGRA S250331o: Upper limits from Swift/BAT-GUANO
  17. IceCube 250406A: DDOTI Optical Observations of the Refined Position
  18. Konus-Wind detection of GRB 250406B (short/hard)
  19. IPN triangulation of GRB 250406B (short/hard)
  20. GRB 250407A: BALROG localization (Fermi Trigger 765733706 / GRB 250407659)
  21. GRB 250407A: Fermi GBM Final Real-time Localization
  22. IceCube-250406A - IceCube observation of a high-energy neutrino candidate track-like event
  23. IceCube 250406.951: COLIBRÍ/DDRAGO Optical Upper Limit
  24. IceCube 250406.951: DDOTI Optical Observations
  25. GRB 250406A: AstroSat CZTI detection
  26. IceCube Alert 250406.95: Global MASTER-Net observations report
  27. Fermi trigger No 765663719: Global MASTER-Net observations report
  28. EP250404a: Multi-band Optical Observations from UCAS-70 and XL-C14
  29. Fermi GRB 250406A: Global MASTER-Net observations report
  30. GRB 250404A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  31. GRB 250406A: Fermi GBM Final Real-time Localization
  32. EP250404a / GRB 250404A: Montarrenti Observatory optical observations
  33. Fermi trigger No 765619921: Global MASTER-Net observations report
  34. Fermi Gamma-ray Burst Monitor trigger 765619921/250406342 is not a GRB
  35. GRB 250404A / EP250404a: RC500 INASAN-Kislovodsk optical upper limit
  36. GRB 250404A / EP250404a: SVOM/GWAC-F60 and F50 observations
  37. EP250404a / GRB 250404A: J band observations by SYSU 80cm telescope
  38. Konus-Wind detection of GRB 250404A / EP250404a
  39. GRB 250404A / EP250404a: Mondy optical observations
  40. EP250404a: refined analysis of the EP-WXT and EP-FXT observations
  41. GRB 250404A / EP250404a: GMG spectroscopic redshift at z ~ 2.627
  42. GRB 250404A / EP250404a: Leavitt Observatory optical counterpart detection
  43. GRB 250402A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  44. EP250402a: Optical upper limit with PD 1.3m observations
  45. GRB 250404A / EP250404a: NOT optical observations
  46. GRB 250331D: Swift-XRT afterglow detection
  47. GRB 250404B: AstroSat CZTI detection of a short burst
  48. GRB 250403A: AstroSat CZTI detection
  49. EP250404a: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
  50. EP250404a: REM optical/NIR observations
  51. EP250404a: Seimei/TriCCS optical counterpart detection
  52. EP250404A: COLIBRÍ/DDRAGO Optical Observations
  53. EP250404A / GRB250404A: Ondrejov D50 optical afterglow detection
  54. EP250404a: LCO optical counterpart detection
  55. Fermi GRB 250404A: Global MASTER-Net observations report
  56. EP250404a: Xinglong decaying optical counterpart
  57. GRB 250403A: Montarrenti Observatory optical detection
  58. GRB 250404A: Fermi GBM Detection
  59. EP250404a: Global MASTER-Net observations report
  60. GRB 250403A: KAIT optical observations
  61. EP250404a: AKO Optical Afterglow Detection
  62. EP250404a: LAST detection of optical counterpart
  63. GRB 250402A: Swift/BAT-GUANO localization skymap of a burst
  64. EP250404a: Xinglong-2.16m spectroscopic redshift
  65. GRB 250403A: Fermi GBM observations
  66. GRB 250327B: VIRT Optical Upper Limit
  67. EP250404a: Mephisto multi-band optical detection
  68. GRB 250331C Swift-BAT refined analysis
  69. GRB 250331B Swift-BAT refined analysis
  70. GRB 250330A Swift-BAT refined analysis
  71. EP250321A: J band upper limit by SYSU 80cm telescope
  72. EP250404a: BOOTES-4/JGT optical afterglow detection
  73. EP250404a: Nanshan/HMT optical counterpart detection
  74. EP250404a: Einstein Probe detection of an X-ray transient
  75. GRB 250404A: Fermi GBM Final Real-time Localization
  76. GRB 250402A: Mondy optical observations
  77. GRB 250402A: Swift/UVOT Upper Limits
  78. EP250402a: Optical upper limit with Kinder observations
  79. GRB 250403A: SVOM/VT optical observation
  80. GRB 250403A: REM NIR afterglow detection
  81. GRB 250403A: LCO optical counterpart detection
  82. IceCube-250330A: MASTER detection of PKS 2032+107 blazar flare with Zhirkov effect
  83. GRB 250403A: JinShan optical observations
  84. GRB 250402A: EP-FXT afterglow detection
  85. GRB 250403A: Optical counterpart detection by LCO.
  86. EP250402a: EP-FXT follow-up observations
  87. GRB 250403A: Swift-XRT observations
  88. GRB 250322A: 10 GHz VLA radio upper limits
  89. Fermi GRB 250403A: Global MASTER-Net observations report
  90. GRB 250403A: GOTO optical counterpart follow-up observations
  91. GRB 250403A: GMG Optical Observation
  92. GRB 250403A: 1.6m Mephisto multi-band optical detection
  93. GRB 250402A: Fermi GBM Observation
  94. GRB 250403A: SVOM/C-GFT optical observations
  95. GRB 250403A: GOTO detection of the optical afterglow
  96. GRB 250402A: Swift-XRT observations
  97. GRB 250403A : SVOM detection of a burst
  98. GRB 250403A: Fermi GBM Final Real-time Localization
  99. GRB 250225B: VLT host galaxy redshift z = 0.950
  100. GRB250402A: SVOM/COLIBRÍ (FM-GFT) Detection of the Optical Counterpart

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