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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"

37166 results found.

  1. GRB 260131A: KAIT optical observations
  2. GRB 251230A: MeerLICHT afterglow detection
  3. GRB 260131A: FTW optical and NIR observations
  4. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  5. GRID detection of GRB 260131A/B
  6. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  7. GRB 260130A: Insight-HXMT/HE detection
  8. GRB 260130A: GECAM-B observation of a short burst
  9. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  10. GRB 260131A/B: EP/FXT X-ray afterglow detection
  11. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  12. GRB 260127B: Insight-HXMT/HE detection
  13. GRB 260127B: GECAM-B observation of a short burst
  14. GRB 260127A: GECAM-B observation
  15. GRB 260131A: NOT spectroscopic redshift z = 1.434
  16. EP260131a: Liverpool Telescope optical upper limits
  17. Konus-Wind detection of GRB 260128A / EP260128a
  18. GRB 260131A: Insight-HXMT/HE detection
  19. Konus-Wind detection of GRB 260131A/B
  20. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  21. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  22. GRB 260131A/B: Fermi GBM Observation
  23. EP260131a: VLT/X-shooter spectroscopic redshift z = 0.937
  24. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  25. GRB 260131B: MAXI/GSC detection
  26. GRB 260131A: Fermi GBM Final Real-time Localization
  27. GRB 260127B: AstroSat CZTI detection
  28. GRB 260130A: Fermi GBM Detection
  29. GRB 260127B: Fermi GBM Detection
  30. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  31. Fermi GRB 260130A: Global MASTER-Net observations report
  32. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  33. GRB 260130A: Fermi GBM Final Real-time Localization
  34. Fermi GRB 260129A: Global MASTER-Net observations report
  35. GRB 260128B: LCO optical upper limits
  36. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  37. IPN triangulation of GRB 260121A
  38. GRB 260127A: Swift-BAT refined analysis
  39. GRB 260129B: Fermi GBM Final Localization
  40. GRB 260128B: SVOM detection of a burst through offline search
  41. GRB 260129A: Fermi GBM Final Localization
  42. IPN triangulation of GRB 260127B (short)
  43. GRB 260127B: Swift-XRT observations
  44. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  45. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  46. Fermi GRB 260127A: Global MASTER-Net observations report
  47. GRB 260127A: Fermi GBM Observation
  48. GRB 260127A: COLIBRÍ optical observations
  49. GRB 260127A: NOT optical observations
  50. GRB 260127B: Swift ToO observations
  51. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  52. GRB 260127A: Swift-XRT refined Analysis
  53. GRB 260127B: GOTO candidate optical counterpart
  54. GRB 260127A: SVOM/C-GFT optical observations
  55. GRB 260127A: Enhanced Swift-XRT position
  56. Fermi GRB 260127B: Global MASTER-Net observations report
  57. GRB 260127B: Fermi GBM Final Real-time Localization
  58. GRB 260127A: Prompt enhanced Swift-XRT position
  59. Swift GRB 260127A: Global MASTER-Net observations report
  60. GRB 260127A: LCO optical afterglow discovery
  61. GRB 260127A: Swift detection of a burst
  62. GRB 260127A: Fermi GBM Final Real-time Localization
  63. GRB 260125A: Swift-XRT observations
  64. EP260126a: Optical upper limit with Kinder observations
  65. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  66. Konus-Wind detection of GRB 260120B
  67. GRB 251222A: SVOM/ECLAIRs refined analysis
  68. GRB 260125A: Swift ToO observations
  69. GRB 260125A: GOTO candidate optical counterpart
  70. Fermi GRB 260125B: Global MASTER-Net observations report
  71. GRB 260125B: Fermi GBM Final Real-time Localization
  72. GRB 260125A: Fermi GBM Final Real-time Localization
  73. GRB 260114A: SVOM/VT optical upper limits
  74. GRB 260120A: AstroSat CZTI detection
  75. GRB 260122B: Swift-BAT refined analysis
  76. GRB 260120B: SVOM/GRM observation
  77. GRB 260120A: GECAM-B observation
  78. GRB 260120B: AstroSat CZTI detection
  79. GRB 260114A: Insight-HXMT/HE detection
  80. GRB 260122B: Swift detection of a burst
  81. EP260119a: Assy AZT-20 optical observations
  82. EP260119a: Mondy and SAO RAS optical upper limits
  83. GRB 260122A: Fermi GBM Final Real-time Localization
  84. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  85. Fermi GRB 260120C: Global MASTER-Net observations report
  86. GRB 260120B: Swift-BAT refined analysis
  87. GRB 260120B: Swift-XRT refined Analysis
  88. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  89. GRB 260120B: Fermi GBM Observation
  90. GRB 260120B: Swift/UVOT Detection
  91. GRB 260120B: COLIBRÍ optical upper limits
  92. GRB 260120B: Enhanced Swift-XRT position
  93. GRB 260120B: SVOM/C-GFT optical counterpart detection
  94. GRB 260120C: Fermi GBM Final Real-time Localization
  95. GRB 260101A: 239Alferov CubeSat detection
  96. GRB 260120B: Swift detection of a burst
  97. GRB 260120B: Fermi GBM Final Real-time Localization
  98. EP260119A: Mondy I-Band Observations
  99. GRB 260114A: Swift/UVOT Upper Limits
  100. EP260119a: Liverpool Telescope optical follow-up observations

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