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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

10363 results found.

  1. LIGO/Virgo/KAGRA S250328ae: DECam DESGW Candidates (Final Epochs)
  2. Konus-Wind detection of GRB 250506A
  3. GRB 250507B: AstroSat CZTI detection
  4. EP250512a/GRB 250512B refined analysis of the EP-WXT and EP-FXT observations
  5. EP250512a: Global MASTER-Net observations report
  6. GRB 250512B/EP250512a:SVOM/VT bright optical counterpart
  7. GRB 250512B: SVOM detection of a burst
  8. EP250512a: Einstein Probe detection of an X-ray transient
  9. EP250511a: Einstein Probe follow-up obsevation and refined analysis
  10. EP250511a: Global MASTER-Net observations report
  11. EP250511a: Einstein Probe detection of an X-ray transient
  12. Fermi GRB 250510C: Global MASTER-Net observations report
  13. GRB 250510B: Swift/BAT-GUANO localization skymap of a burst
  14. GRB 250510A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  15. GRB 250509A: Swift-XRT refined Analysis
  16. GRB 250510A: SVOM possible detection of a burst
  17. Fermi GRB 250509A: Global MASTER-Net observations report
  18. GRB 250509A: Swift detection of a burst
  19. EP250508a: refined analysis of the EP-WXT and EP-FXT observations
  20. GRB 250506A: Swift-XRT afterglow detection
  21. EP250508a: Global MASTER-Net observations report
  22. EP250508a: Einstein Probe detection of an X-ray transient
  23. GRB 250507A: refined SVOM/MXT data analysis
  24. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  25. IceCube Alert 250506.59: Global MASTER-Net observations report
  26. GRB 250430A: Konus-Wind detection and joint Konus-Wind+Swift-BAT spectral analysis
  27. GRB 250506A: REM optical/NIR upper limits
  28. GRB 250506A: Fermi GBM Observation
  29. GRB 250504A: Swift-BAT refined analysis
  30. GRB 250504A: REM optical/NIR observations
  31. GRB 250504A: MeerLICHT optical afterglow detection
  32. Fermi GRB 250504A: Global MASTER-Net observations report
  33. GRB 250504A: Swift detection of a burst
  34. GRB 250502A: Mondy and Tien-Shan Optical Observations
  35. GRB 250502A: Montarrenti Observatory optical detection
  36. GRB 250502A: Swift-XRT afterglow detection
  37. GRB 250502B: AstroSat CZTI detection
  38. GRB 250502A: LCO optical counterpart detection
  39. GRB 250502C: Fermi GBM Final Localization
  40. GRB 250407A: VZLUSAT-2 detection
  41. Fermi-LAT Gamma-ray Observations of IceCube-250429A
  42. GRB 250502B: DDOTI Optical Observations
  43. GRB 250430A: Swift-XRT refined Analysis
  44. GRB 250430A: Swift/UVOT Detection
  45. Fermi GRB 250502B: Global MASTER-Net observations report
  46. GRB 250430A: Swift detection of a burst with optical counterpart
  47. EP250428b: refined analysis of the EP-FXT follow-up observation
  48. EP250428b: SAO RAS optical upper limit
  49. EP250428b: Einstein Probe detection of a fast X-ray transient
  50. Fermi-LAT Gamma-ray Observations of IceCube-250426A
  51. EP250427a: REM optical/NIR afterglow detection
  52. EP250427a: Einstein Probe detection of a fast X-ray transient
  53. IceCube Alert 250426.74: Global MASTER-Net observations report
  54. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  55. Konus-Wind detection of GRB 250424A
  56. Fermi-LAT gamma-ray observations of IceCube-250421A
  57. GRB 250424A: Kilonova-Catcher optical afterglow detection
  58. GRB 250404A / EP250404a: GRBAlpha detection
  59. GRB 250424A: Swift-XRT refined Analysis
  60. GRB 250424A: AstroSat CZTI detection of a bright long burst
  61. GRB 250424A: DDOTI Afterglow Detection
  62. LIGO/Virgo/KAGRA S250328ae: Subaru/PFS Spectroscopic Follow up and Candidates
  63. SVOM/sb25042207: BOOTES-2 early optical upper limit
  64. SVOM/sb25042207: GOTO optical upper limits
  65. GRB 250421A: AstroSat CZTI detection
  66. GRB 250419A: Mephisto Multi-band Optical Detection
  67. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  68. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  69. GRB 250419A: Mondy Continued Optical Observations
  70. Fermi GRB 250421A: Global MASTER-Net observations report
  71. GRB 250421B: AstroSat CZTI detection of a bright long burst
  72. IceCube Alert 250421.71: Global MASTER-Net observations report
  73. GRB 250419A: Liverpool Telescope observations
  74. GRB 250419A: JinShan optical observations
  75. GRB 250416C / EP250416a: SVOM/GRM observation of a burst
  76. GRB 250419A: LCO optical afterglow multi-band observations
  77. GRB 250419A: MASTER optical afterglow observation
  78. Fermi-LAT Gamma-ray Observations of IceCube-250416A
  79. GRB 250419A: Swift-XRT refined Analysis
  80. Konus-Wind detection of GRB 250416C (a counterpart of EP250416a)
  81. EP250416a: refined EP-WXT and EP-FXT analysis
  82. Konus-Wind detection of GRB 250403A
  83. IceCube-250416A: DDOTI Optical Observations
  84. EP250416a: GSP optical upper limit
  85. EP250416a: Global MASTER-Net observations report
  86. EP250416a: Einstein Probe detection of an X-ray transient
  87. IceCube-250416A: Global MASTER-Net observations report
  88. GRB 250413A: AstroSat CZTI detection
  89. GRB 250412A: AstroSat CZTI detection
  90. EP250404a: Nanshan 0.43m Telescope optical observatios
  91. Fermi trigger No 766148493: Global MASTER-Net observations report
  92. Fermi trigger No 766173972: Global MASTER-Net observations report
  93. Fermi GRB 250411A: Global MASTER-Net observations report
  94. GRB 250320B: cubesat Avion detection
  95. Fermi-LAT gamma-ray observations of IceCube-250406A
  96. Konus-Wind detection of GRB 250407A
  97. GRB 250407A: EP-WXT afterglow detection
  98. GRB 250407A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
  99. GRB 250407A: Fermi GBM Detection
  100. GRB 250407A: Swift-XRT afterglow detection

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