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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"

23619 results found.

  1. GRB 260208A: Glowbug gamma-ray detection
  2. GRB 260208B: COLIBRÍ optical observations
  3. GRB 260208A: COLIBRÍ optical observations
  4. GRB 260208B: Fermi-LAT detection
  5. GRB 260208A: Fermi-LAT detection
  6. GRB 260208A: GOTO detection of a potential optical counterpart (GOTO26aob)
  7. EP260131a: VLA detection
  8. GRB 260206A (or XRB from 4U 0513-40): MAXI/GSC detection
  9. GRB 260204A: Swift-XRT observations
  10. GRB 260204A: LCO optical afterglow detection
  11. GRB 260204A: SVOM/VT optical candidate
  12. GRB 260204A: GOTO optical upper limit
  13. GRB 260204A: LCO optical upper limits
  14. GRB 260204A: SVOM detection of a burst
  15. GRB 260121A: 239Alferov CubeSat detection
  16. Konus-Wind detection of GRB 260121A
  17. GRB 260131A: KAIT optical observations
  18. GRB 260131A/AT2026bwg: Observations by the Zwicky Transient Facility
  19. GRB 260131A/B: GTC/OSIRIS+ redshift confimation
  20. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  21. GRB 260127A: GECAM-B observation
  22. EP260131a: COLIBRÍ further observations
  23. Konus-Wind detection of GRB 260128A / EP260128a
  24. Konus-Wind detection of GRB 260131A/B
  25. EP260131a: Xinglong optical upper limit
  26. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  27. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  28. EP260131a: COLIBRÍ observations of slow optical fading
  29. GRB 260131B: MAXI/GSC detection
  30. EP260131a: COLIBRÍ optical observations of the counterpart
  31. GRB 260127B: AstroSat CZTI detection
  32. GRB 260130A: Fermi GBM Detection
  33. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  34. Fermi GRB 260130A: Global MASTER-Net observations report
  35. EP260128a / GRB 260128A: NOT and TNG optical and NIR 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 260128B: SVOM detection of a burst through offline search
  40. IPN triangulation of GRB 260127B (short)
  41. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  42. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  43. EP260128a: NOT optical counterpart candidate
  44. GRB 260127A: COLIBRÍ optical observations
  45. EP260126a: Seimei/TriCCS optical upper limit
  46. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  47. GRB 260127B: GOTO candidate optical counterpart
  48. GRB 260127A: LCO optical afterglow discovery
  49. GRB 260127A: Swift detection of a burst
  50. EP260126a: Optical upper limit with Kinder observations
  51. EP260126a: COLIBRÍ optical upper limits
  52. EP260126a: NOT optical observations
  53. Konus-Wind detection of GRB 260120B
  54. GRB 260125A: GOTO candidate optical counterpart
  55. GRB 260114A: SVOM/VT optical upper limits
  56. GRB 260120A: AstroSat CZTI detection
  57. GRB 260122B: Swift-BAT refined analysis
  58. GRB 260120B: AstroSat CZTI detection
  59. GRB 260122B: Swift detection of a burst
  60. EP260119a: Assy AZT-20 optical observations
  61. EP260119a: Xinglong optical upper limit
  62. GRB 260120B: Swift-BAT refined analysis
  63. GRB 260120B: Swift-XRT refined Analysis
  64. EP260116a: COLIBRÍ further observations
  65. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  66. GRB 260120B: Swift/UVOT Detection
  67. GRB 260120B: COLIBRÍ optical upper limits
  68. GRB 260101A: 239Alferov CubeSat detection
  69. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  70. GRB 260120B: Swift detection of a burst
  71. GRB 251202A: further radio observations with the VLA
  72. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  73. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  74. EP260119a: KAIT optical observations
  75. EP260119a: NOT optical observations
  76. EP260116a: COLIBRÍ detection of a fading optical source
  77. GRB 251208D: SVOM/ECLAIRs refined analysis
  78. GRB 251208D: SVOM/ECLAIRs refined analysis
  79. GRB 260117A: Swift-XRT afterglow detection
  80. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  81. GRB 260115A: AstroSat CZTI detection
  82. EP260119a: COLIBRÍ optical counterpart candidate
  83. GRB 260110A: SVOM detection of a burst through offline search
  84. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  85. Swift trigger on the HMXB 1A 1118-61
  86. GRB 260117A: Swift-XRT observations
  87. EP 260116a: COLIBRÍ optical upper limit
  88. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  89. GRB 260114A: VLT/MUSE spectroscopic observations
  90. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  91. EP260116a: Xinglong optical upper limit
  92. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  93. GRB260114A: STEP/T80S optical limits
  94. GRB 251222A: radio detection with the VLA
  95. Konus-Wind detection of GRB 260114A
  96. GRB 260114A: Swift-XRT refined Analysis
  97. GRB 260114A: 6 GHz VLA observations
  98. GRB 260114A : MITSuME Akeno optical upper limits
  99. GRB 260114A: COLIBRÍ optical upper limits
  100. GRB 260114A: TNG NIR upper limit

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