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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').
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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"

32548 results found.

  1. Konus-Wind detection of GRB 260121A
  2. GRB 260131A/B: OHP/T193 optical observations
  3. GRB 260131A: KAIT optical observations
  4. GRB 251230A: MeerLICHT afterglow detection
  5. GRB 260131A: FTW optical and NIR observations
  6. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  7. GRID detection of GRB 260131A/B
  8. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  9. GRB 260130A: Insight-HXMT/HE detection
  10. GRB 260130A: GECAM-B observation of a short burst
  11. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  12. GRB 260131A/B: EP/FXT X-ray afterglow detection
  13. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  14. GRB 260127B: Insight-HXMT/HE detection
  15. GRB 260127B: GECAM-B observation of a short burst
  16. GRB 260127A: GECAM-B observation
  17. GRB 260131A: NOT spectroscopic redshift z = 1.434
  18. EP260131a: Liverpool Telescope optical upper limits
  19. EP260131a: COLIBRÍ further observations
  20. Konus-Wind detection of GRB 260128A / EP260128a
  21. GRB 260131A: Insight-HXMT/HE detection
  22. Konus-Wind detection of GRB 260131A/B
  23. EP260131a: SVOM/VT optical observation
  24. EP260131a: Xinglong optical upper limit
  25. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  26. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  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: VLT/X-shooter spectroscopic redshift z = 0.937
  31. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  32. EP260131a: COLIBRÍ optical observations of the counterpart
  33. GRB 260127B: AstroSat CZTI detection
  34. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  35. Fermi GRB 260130A: Global MASTER-Net observations report
  36. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  37. Fermi GRB 260129A: Global MASTER-Net observations report
  38. GRB 260128B: LCO optical upper limits
  39. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  40. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  41. IPN triangulation of GRB 260121A
  42. GRB 260127A: Swift-BAT refined analysis
  43. IPN triangulation of GRB 260127B (short)
  44. GRB 260127B: Swift-XRT observations
  45. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  46. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  47. EP260128a: NOT optical counterpart candidate
  48. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  49. EP260128a: Liverpool Telescope optical observations and possible counterpart
  50. EP260128a: LCO optical upper limits
  51. EP260126a: SVOM/VT optical upperlimit
  52. EP260128a: Global MASTER-Net observations report
  53. Fermi GRB 260127A: Global MASTER-Net observations report
  54. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  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. GRB 260127A: NOT optical observations
  59. GRB 260127B: Swift ToO observations
  60. EP260126a: Seimei/TriCCS optical upper limit
  61. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  62. GRB 260127B: GOTO candidate optical counterpart
  63. GRB 260127A: SVOM/C-GFT optical observations
  64. Fermi GRB 260127B: Global MASTER-Net observations report
  65. Swift GRB 260127A: Global MASTER-Net observations report
  66. GRB 260127A: LCO optical afterglow discovery
  67. GRB 260125A: Swift-XRT observations
  68. EP260126a: EP-FXT follow-up observation
  69. EP260126a: Optical upper limit with Kinder observations
  70. EP260126a: Liverpool Telescope optical upper limits
  71. EP260126a: Further NOT optical upper limits
  72. EP260126a: COLIBRÍ optical upper limits
  73. EP260126a: NOT optical observations
  74. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  75. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  76. Konus-Wind detection of GRB 260120B
  77. GRB 251222A: SVOM/ECLAIRs refined analysis
  78. GRB 260125A: Swift ToO observations
  79. GRB 260125A: GOTO candidate optical counterpart
  80. Fermi GRB 260125B: Global MASTER-Net observations report
  81. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  82. GRB 260114A: SVOM/VT optical upper limits
  83. GRB 260120A: AstroSat CZTI detection
  84. GRB 260122B: Swift-BAT refined analysis
  85. GRB 260120B: SVOM/GRM observation
  86. GRB 260120A: GECAM-B observation
  87. GRB 260120B: AstroSat CZTI detection
  88. GRB 260114A: Insight-HXMT/HE detection
  89. EP260119a: Assy AZT-20 optical observations
  90. EP260119a: Mondy and SAO RAS optical upper limits
  91. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  92. EP260119a: Xinglong optical upper limit
  93. Fermi GRB 260120C: Global MASTER-Net observations report
  94. GRB 260120B: Swift-BAT refined analysis
  95. EP260116a: COLIBRÍ further observations
  96. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  97. GRB 260120B: Fermi GBM Observation
  98. EP260105a: GTC/HiPERCAM optical observations
  99. GRB 260120B: Swift/UVOT Detection
  100. GRB 260120B: COLIBRÍ optical upper limits

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