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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').
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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"

32717 results found.

  1. GRB 260127B: AstroSat CZTI detection
  2. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  3. Fermi GRB 260130A: Global MASTER-Net observations report
  4. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  5. Fermi GRB 260129A: Global MASTER-Net observations report
  6. GRB 260128B: LCO optical upper limits
  7. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  8. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  9. IPN triangulation of GRB 260121A
  10. GRB 260127A: Swift-BAT refined analysis
  11. IPN triangulation of GRB 260127B (short)
  12. GRB 260127B: Swift-XRT observations
  13. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  14. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  15. EP260128a: NOT optical counterpart candidate
  16. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  17. EP260128a: Liverpool Telescope optical observations and possible counterpart
  18. EP260128a: LCO optical upper limits
  19. EP260126a: SVOM/VT optical upperlimit
  20. EP260128a: Global MASTER-Net observations report
  21. Fermi GRB 260127A: Global MASTER-Net observations report
  22. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  23. GRB 260127A: Fermi GBM Observation
  24. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  25. GRB 260127A: COLIBRÍ optical observations
  26. GRB 260127A: NOT optical observations
  27. GRB 260127B: Swift ToO observations
  28. EP260126a: Seimei/TriCCS optical upper limit
  29. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  30. GRB 260127B: GOTO candidate optical counterpart
  31. GRB 260127A: SVOM/C-GFT optical observations
  32. Fermi GRB 260127B: Global MASTER-Net observations report
  33. Swift GRB 260127A: Global MASTER-Net observations report
  34. GRB 260127A: LCO optical afterglow discovery
  35. GRB 260125A: Swift-XRT observations
  36. EP260126a: EP-FXT follow-up observation
  37. EP260126a: Optical upper limit with Kinder observations
  38. EP260126a: Liverpool Telescope optical upper limits
  39. EP260126a: Further NOT optical upper limits
  40. EP260126a: COLIBRÍ optical upper limits
  41. EP260126a: NOT optical observations
  42. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  43. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  44. Konus-Wind detection of GRB 260120B
  45. GRB 251222A: SVOM/ECLAIRs refined analysis
  46. GRB 260125A: Swift ToO observations
  47. GRB 260125A: GOTO candidate optical counterpart
  48. Fermi GRB 260125B: Global MASTER-Net observations report
  49. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 260114A: SVOM/VT optical upper limits
  51. GRB 260120A: AstroSat CZTI detection
  52. GRB 260122B: Swift-BAT refined analysis
  53. GRB 260120B: SVOM/GRM observation
  54. GRB 260120A: GECAM-B observation
  55. GRB 260120B: AstroSat CZTI detection
  56. GRB 260114A: Insight-HXMT/HE detection
  57. EP260119a: Assy AZT-20 optical observations
  58. EP260119a: Mondy and SAO RAS optical upper limits
  59. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  60. EP260119a: Xinglong optical upper limit
  61. Fermi GRB 260120C: Global MASTER-Net observations report
  62. GRB 260120B: Swift-BAT refined analysis
  63. EP260116a: COLIBRÍ further observations
  64. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  65. GRB 260120B: Fermi GBM Observation
  66. EP260105a: GTC/HiPERCAM optical observations
  67. GRB 260120B: Swift/UVOT Detection
  68. GRB 260120B: COLIBRÍ optical upper limits
  69. GRB 260120B: SVOM/C-GFT optical counterpart detection
  70. GRB 260101A: 239Alferov CubeSat detection
  71. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  72. EP260119A: Mondy I-Band Observations
  73. GRB 260114A: Swift/UVOT Upper Limits
  74. EP260119a: Liverpool Telescope optical follow-up observations
  75. GRB 251202A: further radio observations with the VLA
  76. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  77. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  78. EP260119a: KAIT optical observations
  79. EP260119a: SVOM/VT optical observation
  80. EP260119a: update of EP-FXT follow-up observation
  81. EP260119a: NOT optical observations
  82. EP260119a: SAO RAS optical observations
  83. EP260116a: COLIBRÍ detection of a fading optical source
  84. GRB 251208D: SVOM/ECLAIRs refined analysis
  85. GRB 251208D: SVOM/ECLAIRs refined analysis
  86. GRB 260117A: Swift-XRT afterglow detection
  87. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  88. EP260119a: Global MASTER-Net observations report
  89. GRB 260115A: AstroSat CZTI detection
  90. EP260119a: LCO optical observations
  91. GRB 260117A: ZTSh optical upper limit
  92. EP260119a: COLIBRÍ optical counterpart candidate
  93. EP260119a: preliminary result from the EP-FXT observation
  94. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  95. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  96. Swift trigger on the HMXB 1A 1118-61
  97. GRB 260117A: SVOM/VT optical candidate
  98. GRB 260117A: SVOM/C-GFT upper limit
  99. GRB 260117A: Swift ToO observations
  100. EP 260116a: COLIBRÍ optical upper limit

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