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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"

28231 results found.

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

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