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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"

38193 results found.

  1. Fermi GBM Sub-Threshold Detection of GRB 251105B
  2. GRB 251103B: Swift/UVOT Upper Limits
  3. GRB 251105B: SVOM/GRM observation of a possible short burst with extended emission
  4. Fermi GRB 251105A: Global MASTER-Net observations report
  5. GRB 251105A: Fermi GBM Final Real-time Localization
  6. Fermi Gamma-ray Burst Monitor trigger 783986701/251104920 is not a GRB
  7. GRB 251103B: Fermi GBM observation
  8. GRB 251104A: SVOM detection of a burst
  9. GRB 251028A: Insight-HXMT/HE detection
  10. GRB 251103A: Optical afterglow detection by ZTF’s public survey
  11. GRB 251103A: WFST optical observations
  12. EP251102a: OHP/T193 optical observations
  13. GRB 251103A: OHP/T193 optical observations
  14. GRB 251103A: Xinglong 2.16m optical detection
  15. GRB 251103A: Insight-HXMT detection
  16. GRB 251103A: KAIT optical observations
  17. GRB 251103B: Nanshan/HMT optical upper limit
  18. GRB 251013C: 7DT detection and Medium-band SED of Afterglow
  19. GRB 251103A: Swift/BAT-GUANO arcminute localization of a burst
  20. GRB 251103B: MITSuME Akeno optical upper limits
  21. GRB 251103B: Swift-XRT refined Analysis
  22. Fermi GRB 251103A: Global MASTER-Net observations report
  23. GRB 251103A: J-band detection with WINTER
  24. Swift GRB 251103B: Global MASTER-Net observations report
  25. GRB 251103B: GROWTH-India Telescope optical upper limits
  26. GRB 251103A: Kilonova-Catcher optical afterglow detection
  27. GRB 251103B: Enhanced Swift-XRT position
  28. GRB 251103B: Prompt enhanced Swift-XRT position
  29. GRB 251103B: Swift detection of a burst
  30. GRB 251103B: Fermi GBM Final Real-time Localization
  31. GRB 251103A: Swift/UVOT Detection
  32. GRB 251103A: Fermi GBM Observation
  33. GRB 251103A: SVOM/GRM observation
  34. GRB 251103A: Swift-XRT afterglow detection
  35. GRB 251103A: SVOM/COLIBRÍ (FM-GFT) optical observations
  36. GRB 251025B: OHP/T193 optical upper limit
  37. GRB 251103A: LCO optical observation
  38. GRB 251103A: GOTO optical afterglow detection
  39. GRB 251102A: AstroSat CZTI detection
  40. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical counterpart
  41. GRB 251103A: NOT spectroscopic redshift z = 0.76
  42. GRB 251103A: BOOTES-2/TELMA optical afterglow
  43. GRB 251103A: LCO optical afterglow detection
  44. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  45. GRB 251103A: Fermi GBM Final Localization
  46. GRB 251103A: NOT optical afterglow candidate
  47. GRB 251103A: SVOM detection of a bright burst
  48. GRB 251102B: Fermi GBM Final Real-time Localization
  49. Fermi GRB 251102A: Global MASTER-Net observations report
  50. GRB 251102A: Fermi GBM Final Real-time Localization
  51. GRB 251031A: Fermi GBM Observation
  52. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  53. Konus-Wind detection of GRB 251028A
  54. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  55. GRB 251031A: Fermi GBM Final Real-time Localization
  56. GRB 251025C: SVOM/GRM observation
  57. GRB 251028A: GECAM-B detection
  58. GRB 251028A: SVOM/GRM observation
  59. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  60. GRB 251028A: Fermi GBM Observation
  61. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  62. GRB 251022A: Swift-XRT confirmation of fading
  63. GRB 251026B: LBT near-infrared observations
  64. GRB 250926B: VZLUSAT-2 detection
  65. GRB 250926A: VZLUSAT-2 detection
  66. GRB 250925A: VZLUSAT-2 detection
  67. GRB 251026B: Fermi GBM Observation
  68. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  69. GRB 251026A/EP251026a: EP-FXT follow-up observation
  70. GRB 251028B: Fermi/GBM observation
  71. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 251028B: Glowbug gamma-ray detection
  73. GRB 251028A: Glowbug gamma-ray detection
  74. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  75. Fermi GRB 251028B: Global MASTER-Net observations report
  76. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  77. GRB 251028B: Fermi GBM Final Localization Correction
  78. GRB251025B: 3.6m DOT Optical Observations
  79. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  80. GRB 251028A: MAXI/GSC detection
  81. GRB 251028A: Fermi GBM Final Real-time Localization
  82. SVOM trigger sb25102702/GRB 251027A is not a GRB
  83. GRB 251025B: Swift-XRT confirmation of fading
  84. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  85. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  86. GRB 251025C: Glowbug gamma-ray detection
  87. GRB 251023B: Swift-UVOT Upper Limits
  88. Konus-Wind detection of GRB 251022A
  89. GRB 251027A: Swift-XRT observations
  90. GRB 251022A: SVOM/GRM observation
  91. GRB 251026B: Swift ToO observations
  92. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  93. GRB 251027A: LCO optical upper limit
  94. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  96. GRB 251023B / EP251023b: Mondy optical upper limit
  97. GRB 251017A: INASAN-Kislovodsk optical observations
  98. GRB 251026A: Mondy optical upper limit
  99. GRB 251025B: Mondy optical observations
  100. GRB 251025B: Kilonova-Catcher optical afterglow detection

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