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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"

28232 results found.

  1. GRB 260210A: Glowbug gamma-ray detection
  2. GRB 260208C: AstroSat CZTI detection
  3. EP260210a: COLIBRÍ optical upper limit
  4. EP260210a: SVOM/C-GFT upper limit
  5. EP260210a: Einstein Probe detection of an X-ray transient
  6. GRB 260207B: AstroSat CZTI detection
  7. GRB 260208C: SVOM/GRM observation
  8. GRB 260204A: Swift-XRT afterglow detection
  9. GRB 260208B: AstroSat CZTI detection of a bright long burst
  10. GRB260208A: Liverpool Telescope optical follow-up observations
  11. GRB 260208A: Glowbug gamma-ray detection
  12. GRB 260208A: NuSTAR detection of prompt emission
  13. GRB 260208A: Fermi GBM Observation
  14. Fermi GRB 260209A: Global MASTER-Net observations report
  15. GRB 260208B: Swift-XRT observations
  16. GRB 260131A/B: continued Mondy optical observations
  17. GRB 260204A: Swift/UVOT Upper Limits
  18. GRB 260208B: COLIBRÍ optical observations
  19. GRB 260208A: Mondy optical observations
  20. GRB 260208A: 1.3m DFOT optical detection
  21. GRB 260208A: COLIBRÍ optical observations
  22. GRB 260208B: EP-FXT observation
  23. Fermi GRB 260208C: Global MASTER-Net observations report
  24. GRB 260208B: SVOM/VT optical candidate
  25. GRB 260208A: GECAM-B observation of a bright burst
  26. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  27. GRB 260208A: SVOM/VT optical observation
  28. Fermi GRB 260208D: Global MASTER-Net observations report
  29. GRB 260208A: Swift-XRT observations
  30. GRB 260208B: SVOM/GRM observation of a bright burst
  31. GRB 260208B: Fermi GBM Detection
  32. LAT GRB 260208B: Global MASTER-Net observations report
  33. GRB 260208A : MASTER bright optical transient inside retracted Fermi error-box
  34. GRB 260208B: BALROG localization (Fermi Trigger 792237169 / GRB 260208412)
  35. Fermi GRB 260208A: Global MASTER-Net observations report
  36. GRB 260207B: Fermi GBM Detection of a Short Burst with Extended Emission
  37. GRB 260131A/B: Mondy and Terskol optical observations
  38. Fermi GRB 260207B: Global MASTER-Net observations report
  39. GRB 260206A: Swift-XRT observations
  40. Fermi trigger No 792135758: Global MASTER-Net observations report
  41. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  42. GRB 260204A: Swift-XRT observations
  43. GRB 260204A: SVOM/VT optical candidate
  44. GRB 260204A : MASTER Global robotic net optical observations
  45. Fermi GBM Sub-Threshold Detection of GRB 260204A
  46. GRB 260204A: LCO optical upper limits
  47. EP260110a: Late GTC/EMIR near-infrared observations
  48. GRB 260121A: 239Alferov CubeSat detection
  49. GRB 260131A: KAIT optical observations
  50. GRB 251230A: MeerLICHT afterglow detection
  51. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  52. GRB 260130A: Insight-HXMT/HE detection
  53. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  54. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  55. GRB 260127A: GECAM-B observation
  56. EP260131a: Liverpool Telescope optical upper limits
  57. EP260131a: COLIBRÍ further observations
  58. EP260131a: SVOM/VT optical observation
  59. EP260131a: Xinglong optical upper limit
  60. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  61. GRB 260131A/B: Fermi GBM Observation
  62. EP260131a: COLIBRÍ observations of slow optical fading
  63. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  64. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  65. GRB 260131B: MAXI/GSC detection
  66. EP260131a: COLIBRÍ optical observations of the counterpart
  67. EP260131a: Las Cumbres detection of an optical counterpart
  68. GRB 260127B: AstroSat CZTI detection
  69. GRB 260130A: Fermi GBM Detection
  70. EP260131a: Einstein Probe detection of an X-ray transient
  71. GRB 260127B: Fermi GBM Detection
  72. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  73. Fermi GRB 260130A: Global MASTER-Net observations report
  74. Fermi GRB 260129A: Global MASTER-Net observations report
  75. GRB 260128B: LCO optical upper limits
  76. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  77. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  78. GRB 260127A: Swift-BAT refined analysis
  79. GRB 260127B: Swift-XRT observations
  80. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  81. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  82. EP260128a: NOT optical counterpart candidate
  83. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  84. EP260128a: Liverpool Telescope optical observations and possible counterpart
  85. EP260128a: LCO optical upper limits
  86. EP260128a: Global MASTER-Net observations report
  87. EP260128a: Einstein Probe detection of an X-ray transient
  88. Fermi GRB 260127A: Global MASTER-Net observations report
  89. GRB 260127A: Fermi GBM Observation
  90. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  91. GRB 260127A: COLIBRÍ optical observations
  92. EP260126a: Seimei/TriCCS optical upper limit
  93. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  94. GRB 260127A: Swift-XRT refined Analysis
  95. GRB 260127A: SVOM/C-GFT optical observations
  96. GRB 260127A: Enhanced Swift-XRT position
  97. Fermi GRB 260127B: Global MASTER-Net observations report
  98. Swift GRB 260127A: Global MASTER-Net observations report
  99. GRB 260127A: LCO optical afterglow discovery
  100. GRB 260127A: Swift detection of a burst

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