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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"

28098 results found.

  1. Fermi GRB 260208A: Global MASTER-Net observations report
  2. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  3. GRB 260131A/B: Mondy and Terskol optical observations
  4. Fermi GRB 260207B: Global MASTER-Net observations report
  5. GRB 260206A: Swift-XRT observations
  6. Fermi trigger No 792135758: Global MASTER-Net observations report
  7. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  8. GRB 260204A: Swift-XRT observations
  9. GRB 260204A: SVOM/VT optical candidate
  10. GRB 260204A : MASTER Global robotic net optical observations
  11. Fermi GBM Sub-Threshold Detection of GRB 260204A
  12. GRB 260204A: LCO optical upper limits
  13. EP260110a: Late GTC/EMIR near-infrared observations
  14. GRB 260121A: 239Alferov CubeSat detection
  15. GRB 260131A: KAIT optical observations
  16. GRB 251230A: MeerLICHT afterglow detection
  17. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  18. GRB 260130A: Insight-HXMT/HE detection
  19. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  20. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  21. GRB 260127A: GECAM-B observation
  22. EP260131a: Liverpool Telescope optical upper limits
  23. EP260131a: COLIBRÍ further observations
  24. EP260131a: SVOM/VT optical observation
  25. EP260131a: Xinglong optical upper limit
  26. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  27. GRB 260131A/B: Fermi GBM Observation
  28. EP260131a: COLIBRÍ observations of slow optical fading
  29. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  30. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  31. GRB 260131B: MAXI/GSC detection
  32. EP260131a: COLIBRÍ optical observations of the counterpart
  33. EP260131a: Las Cumbres detection of an optical counterpart
  34. GRB 260127B: AstroSat CZTI detection
  35. GRB 260130A: Fermi GBM Detection
  36. EP260131a: Einstein Probe detection of an X-ray transient
  37. GRB 260127B: Fermi GBM Detection
  38. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  39. Fermi GRB 260130A: Global MASTER-Net observations report
  40. Fermi GRB 260129A: Global MASTER-Net observations report
  41. GRB 260128B: LCO optical upper limits
  42. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  43. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  44. GRB 260127A: Swift-BAT refined analysis
  45. GRB 260127B: Swift-XRT observations
  46. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  47. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  48. EP260128a: NOT optical counterpart candidate
  49. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  50. EP260128a: Liverpool Telescope optical observations and possible counterpart
  51. EP260128a: LCO optical upper limits
  52. EP260128a: Global MASTER-Net observations report
  53. EP260128a: Einstein Probe detection of an X-ray transient
  54. Fermi GRB 260127A: Global MASTER-Net observations report
  55. GRB 260127A: Fermi GBM Observation
  56. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 260127A: COLIBRÍ optical observations
  58. EP260126a: Seimei/TriCCS optical upper limit
  59. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  60. GRB 260127A: Swift-XRT refined Analysis
  61. GRB 260127A: SVOM/C-GFT optical observations
  62. GRB 260127A: Enhanced Swift-XRT position
  63. Fermi GRB 260127B: Global MASTER-Net observations report
  64. Swift GRB 260127A: Global MASTER-Net observations report
  65. GRB 260127A: LCO optical afterglow discovery
  66. GRB 260127A: Swift detection of a burst
  67. GRB 260125A: Swift-XRT observations
  68. EP260126a: Optical upper limit with Kinder observations
  69. EP260126a: Liverpool Telescope optical upper limits
  70. EP260126a: Further NOT optical upper limits
  71. EP260126a: COLIBRÍ optical upper limits
  72. EP260126a: NOT optical observations
  73. EP260126a: Einstein Probe detection of a fast X-ray transient
  74. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  75. GRB 251222A: SVOM/ECLAIRs refined analysis
  76. GRB 260125A: GOTO candidate optical counterpart
  77. Fermi GRB 260125B: Global MASTER-Net observations report
  78. GRB 260114A: SVOM/VT optical upper limits
  79. GRB 260122B: Swift-BAT refined analysis
  80. GRB 260120B: SVOM/GRM observation
  81. Swift GRB260122.97: Global MASTER-Net observations report
  82. EP260119a: Assy AZT-20 optical observations
  83. EP260119a: Mondy and SAO RAS optical upper limits
  84. EP260119a: Xinglong optical upper limit
  85. Fermi GRB 260120C: Global MASTER-Net observations report
  86. GRB 260120B: Swift-BAT refined analysis
  87. GRB 260120B: Swift-XRT refined Analysis
  88. EP260116a: COLIBRÍ further observations
  89. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  90. GRB 260120B: Fermi GBM Observation
  91. EP260105a: GTC/HiPERCAM optical observations
  92. GRB 260120B: Swift/UVOT Detection
  93. GRB 260120B: COLIBRÍ optical upper limits
  94. SVOM GRB260121.06: Global MASTER-Net observations report
  95. GRB 260120B: Enhanced Swift-XRT position
  96. GRB 260120B: SVOM/C-GFT optical counterpart detection
  97. GRB 260101A: 239Alferov CubeSat detection
  98. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  99. GRB 260120B: Swift detection of a burst
  100. Swift GRB260120B: Global MASTER-Net observations report

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