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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"

4252 results found.

  1. GRB 250628B: SVOM detection of a long burst
  2. Fermi GRB 250626A: Global MASTER-Net observations report
  3. GRB 250625A: Leavitt Observatory afterglow detection
  4. Fermi trigger No 772190032: Global MASTER-Net observations report
  5. GRB 250621B: SVOM/GRM detection of a possible magnetar X-ray burst
  6. GRB 250619B: Fermi GBM Observation
  7. GRB 250615A/EP250615a: FTW optical and NIR observations
  8. GRB 250617B: Ondrejov D50 optical afterglow detection
  9. EP-WXT trigger 01709178875: confirmation of a stellar flare by BOOTES-6
  10. Fermi trigger No 771424081: Global MASTER-Net observations report
  11. EP250612a: Global MASTER-Net observations report
  12. EP250610a: SVOM/VT optical upper limit
  13. Fermi trigger No 771072240: Global MASTER-Net observations report
  14. GRB 250608A: SVOM/GRM detection of a possible magnetar X-ray burst
  15. GRB 250529A: GOTO optical counterpart candidate (GOTO25dea/AT 2025ndt)
  16. Fermi trigger No 770867684: Global MASTER-Net observations report
  17. Konus-Wind detection of GRB 250601A
  18. GRB 250601A: Fermi GBM Observation
  19. Fermi GRB 250601A: Global MASTER-Net observations report
  20. GRB 250601A: Swift/BAT-GUANO arcminute localization of a likely short burst
  21. GRB 250601A: Fermi GBM Final Real-time Localization
  22. GRB 250521C/AT2025mgj: NOT optical observations of the afterglow candidate
  23. GRB 250530A: SVOM/VT optical upper limit
  24. GRB 250529B: Fermi GBM Final Real-time Localization
  25. GRB 250529A: Fermi GBM Final Real-time Localization
  26. GRB 250527B / MAXI J1450-527 : MAXI/GSC detection
  27. Fermi GRB 250522B: Global MASTER-Net observations report
  28. GRB 250521B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  29. Konus-Wind detection of GRB 250516A
  30. GRB 250515A: NOT classification of GOTO25cqo as a type-Ia SN
  31. GRB 250516A: Swift detection of a burst
  32. GRB 250516A: Fermi GBM Final Real-time Localization
  33. GRB 250507B: AstroSat CZTI detection
  34. Fermi GRB 250510C: Global MASTER-Net observations report
  35. Fermi GRB 250510B: Global MASTER-Net observations report
  36. GRB 250509A: Fermi GBM Final Real-time Localization
  37. GRB 250506A: NOT optical upper limits
  38. GRB 250506A: Swift XRT observations and possible counterpart detection
  39. GRB 250506A: TRT optical observations
  40. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  41. GRB 250504A: MeerLICHT optical afterglow detection
  42. Fermi GRB 250504A: Global MASTER-Net observations report
  43. Swift GRB250504.98: Global MASTER-Net observations report
  44. Fermi-LAT Gamma-ray Observations of IceCube-250429A
  45. GRB 250430A: Leavitt Observatory optical upper limit
  46. GRB 250430A : MITSuME Akeno optical upper limits
  47. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  48. GRB 250430A: AKO Optical Afterglow Detection
  49. Swift GRB250430.73: Global MASTER-Net observations report
  50. EP250427a/GRB250427A: HCT optical follow-up
  51. EP250428b: SVOM/VT upper limit
  52. EP250428b: SAO RAS optical upper limit
  53. EP250428b: LAST optical upper limit
  54. IceCube-250429A - IceCube observation of a high-energy neutrino candidate track-like event
  55. EP250428b: Global MASTER-Net observations report
  56. EP250427a/GRB 250427A: FTW optical and NIR observations of the counterpart
  57. EP250427a: TRT optical counterpart detection
  58. EP 250427a: BOOTES-7 optical afterglow candidate
  59. GRB 250424A: SVOM/VT optical observation
  60. GRB 250419A: Mondy Optical Observations
  61. GRB 250424A: Swift/UVOT Detection
  62. GRB250419A: VLA radio detection
  63. GRB 250419A: Mephisto Multi-band Optical Detection
  64. GRB 250419A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations.
  65. GRB 250419A: Optical Observations via Virtual Telescope Project
  66. IceCube Alert 250421.71: Global MASTER-Net observations report
  67. EP250421a: JinShan likely optical counterpart
  68. The EP-WXT trigger 01709135179: Kinder optical counterpart candidate
  69. GRB 250419A: Swift/UVOT Follow up
  70. GRB 250419A: AKO Optical Afterglow Detection
  71. GRB 250419A: SVOM/VT optical bright counterpart confirmation
  72. GRB 250419A: SVOM detection of a soft burst
  73. GRB 250412A: AstroSat CZTI detection
  74. EP250404a: Nanshan 0.43m Telescope optical observatios
  75. Fermi trigger No 766148493: Global MASTER-Net observations report
  76. Fermi trigger No 766173972: Global MASTER-Net observations report
  77. Fermi GRB 250407A: Global MASTER-Net observations report
  78. Fermi GRB 250406A: Global MASTER-Net observations report
  79. GRB 250402A: Mondy optical observations
  80. EP250402a: Einstein Probe detection of a fast X-ray transient
  81. Fermi GRB 250331E: Global MASTER-Net observations report
  82. GRB 250329A: AbAO, Mondy and SAO RAS optical upper limits
  83. IceCube-250330A: Upper limits from a search for additional neutrino events in IceCube
  84. SVOM/sb25033102: SVOM detection of an X-ray transient
  85. GRB 250328A: 1.6m Mephisto optical observations
  86. GRB 250327B: ALMA detection
  87. GRB 250327B: VLA detection
  88. GRB 250327B: SVOM/COLIBRÍ (F-GFT) Further Observations
  89. GRB 250329B: 1.6m Mephisto Optical Upper Limits
  90. GRB250329A: REM optical afterglow detection
  91. GRB 250329A: Swift-XRT afterglow detection
  92. GRB 250329A: Fading optical counterpart detection by LCO.
  93. GRB 250328A: SVOM/COLIBRÍ (F-GFT) optical afterglow candidate
  94. GRB 250328A: VLT/HAWK-I near-infrared afterglow candidate
  95. GRB 250329A: SVOM/VT optical counterpart confirmation
  96. GRB 250329A: SVOM/COLIBRÍ (F-GFT) Detection of a Bright Optical Counterpart Candidate
  97. GRB 250327B: further optical observations by LCOGT
  98. GRB 250327B: SVOM/VT optically bright counterpart
  99. GRB 250327B: SAO RAS optical candidate
  100. IPN triangulation of GRB 250322B

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