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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"

32720 results found.

  1. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  2. EP260131a: VLT/X-shooter spectroscopic redshift z = 0.937
  3. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  4. EP260131a: COLIBRÍ optical observations of the counterpart
  5. GRB 260127B: AstroSat CZTI detection
  6. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  7. Fermi GRB 260130A: Global MASTER-Net observations report
  8. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  9. Fermi GRB 260129A: Global MASTER-Net observations report
  10. GRB 260128B: LCO optical upper limits
  11. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  12. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  13. IPN triangulation of GRB 260121A
  14. GRB 260127A: Swift-BAT refined analysis
  15. IPN triangulation of GRB 260127B (short)
  16. GRB 260127B: Swift-XRT observations
  17. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  18. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  19. EP260128a: NOT optical counterpart candidate
  20. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  21. EP260128a: Liverpool Telescope optical observations and possible counterpart
  22. EP260128a: LCO optical upper limits
  23. EP260126a: SVOM/VT optical upperlimit
  24. EP260128a: Global MASTER-Net observations report
  25. Fermi GRB 260127A: Global MASTER-Net observations report
  26. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  27. GRB 260127A: Fermi GBM Observation
  28. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 260127A: COLIBRÍ optical observations
  30. GRB 260127A: NOT optical observations
  31. GRB 260127B: Swift ToO observations
  32. EP260126a: Seimei/TriCCS optical upper limit
  33. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  34. GRB 260127B: GOTO candidate optical counterpart
  35. GRB 260127A: SVOM/C-GFT optical observations
  36. Fermi GRB 260127B: Global MASTER-Net observations report
  37. Swift GRB 260127A: Global MASTER-Net observations report
  38. GRB 260127A: LCO optical afterglow discovery
  39. GRB 260125A: Swift-XRT observations
  40. EP260126a: EP-FXT follow-up observation
  41. EP260126a: Optical upper limit with Kinder observations
  42. EP260126a: Liverpool Telescope optical upper limits
  43. EP260126a: Further NOT optical upper limits
  44. EP260126a: COLIBRÍ optical upper limits
  45. EP260126a: NOT optical observations
  46. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  47. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  48. Konus-Wind detection of GRB 260120B
  49. GRB 251222A: SVOM/ECLAIRs refined analysis
  50. GRB 260125A: Swift ToO observations
  51. GRB 260125A: GOTO candidate optical counterpart
  52. Fermi GRB 260125B: Global MASTER-Net observations report
  53. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  54. GRB 260114A: SVOM/VT optical upper limits
  55. GRB 260120A: AstroSat CZTI detection
  56. GRB 260122B: Swift-BAT refined analysis
  57. GRB 260120B: SVOM/GRM observation
  58. GRB 260120A: GECAM-B observation
  59. GRB 260120B: AstroSat CZTI detection
  60. GRB 260114A: Insight-HXMT/HE detection
  61. EP260119a: Assy AZT-20 optical observations
  62. EP260119a: Mondy and SAO RAS optical upper limits
  63. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  64. EP260119a: Xinglong optical upper limit
  65. Fermi GRB 260120C: Global MASTER-Net observations report
  66. GRB 260120B: Swift-BAT refined analysis
  67. EP260116a: COLIBRÍ further observations
  68. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  69. GRB 260120B: Fermi GBM Observation
  70. EP260105a: GTC/HiPERCAM optical observations
  71. GRB 260120B: Swift/UVOT Detection
  72. GRB 260120B: COLIBRÍ optical upper limits
  73. GRB 260120B: SVOM/C-GFT optical counterpart detection
  74. GRB 260101A: 239Alferov CubeSat detection
  75. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  76. EP260119A: Mondy I-Band Observations
  77. GRB 260114A: Swift/UVOT Upper Limits
  78. EP260119a: Liverpool Telescope optical follow-up observations
  79. GRB 251202A: further radio observations with the VLA
  80. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  81. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  82. EP260119a: KAIT optical observations
  83. EP260119a: SVOM/VT optical observation
  84. EP260119a: update of EP-FXT follow-up observation
  85. EP260119a: NOT optical observations
  86. EP260119a: SAO RAS optical observations
  87. EP260116a: COLIBRÍ detection of a fading optical source
  88. GRB 251208D: SVOM/ECLAIRs refined analysis
  89. GRB 251208D: SVOM/ECLAIRs refined analysis
  90. GRB 260117A: Swift-XRT afterglow detection
  91. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  92. EP260119a: Global MASTER-Net observations report
  93. GRB 260115A: AstroSat CZTI detection
  94. EP260119a: LCO optical observations
  95. GRB 260117A: ZTSh optical upper limit
  96. EP260119a: COLIBRÍ optical counterpart candidate
  97. EP260119a: preliminary result from the EP-FXT observation
  98. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  99. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  100. Swift trigger on the HMXB 1A 1118-61

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