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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"

32740 results found.

  1. GRB 260130A: Insight-HXMT/HE detection
  2. GRB 260130A: GECAM-B observation of a short burst
  3. GRB 260131A/B (AT2026bwg): J-band observations by SYSU 80cm infrared telescope
  4. GRB 260131A/B: EP/FXT X-ray afterglow detection
  5. GRB 260131A/B (AT2026bwg): COLIBRÍ further optical observations
  6. GRB 260127B: Insight-HXMT/HE detection
  7. GRB 260127B: GECAM-B observation of a short burst
  8. GRB 260127A: GECAM-B observation
  9. GRB 260131A: NOT spectroscopic redshift z = 1.434
  10. EP260131a: Liverpool Telescope optical upper limits
  11. EP260131a: COLIBRÍ further observations
  12. Konus-Wind detection of GRB 260128A / EP260128a
  13. GRB 260131A: Insight-HXMT/HE detection
  14. Konus-Wind detection of GRB 260131A/B
  15. EP260131a: SVOM/VT optical observation
  16. EP260131a: Xinglong optical upper limit
  17. GRB 260131A/B (AT2026bwg): COLIBRÍ optical observations and confirmation of fading
  18. GRB 260131A/B: GOTO candidate optical counterpart consistent with the MAXI localisation
  19. GRB 260131A/B: Fermi GBM Observation
  20. EP260131a: COLIBRÍ observations of slow optical fading
  21. EP260131a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  22. EP260131a: VLT/X-shooter spectroscopic redshift z = 0.937
  23. EP260131a: NOT early detection of the counterpart in "rapid response mode"
  24. EP260131a: COLIBRÍ optical observations of the counterpart
  25. GRB 260127B: AstroSat CZTI detection
  26. EP260128a / GRB 260128A: COLIBRÍ optical upper limit
  27. Fermi GRB 260130A: Global MASTER-Net observations report
  28. EP260128a / GRB 260128A: NOT and TNG optical and NIR upper limits
  29. Fermi GRB 260129A: Global MASTER-Net observations report
  30. GRB 260128B: LCO optical upper limits
  31. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  32. EP260128a: J band upper limit by SYSU 80cm infrared telescope
  33. IPN triangulation of GRB 260121A
  34. GRB 260127A: Swift-BAT refined analysis
  35. IPN triangulation of GRB 260127B (short)
  36. GRB 260127B: Swift-XRT observations
  37. GRB 260127A: INASAN-Kislovodsk, SAO RAS, and Terskol K-800 optical observations
  38. GRB 260128A / EP260128a: Fermi-GBM Sub-Threshold Detection
  39. EP260128a: NOT optical counterpart candidate
  40. EP260128a: refined analysis of the EP-WXT and autonomous EP-FXT observations
  41. EP260128a: Liverpool Telescope optical observations and possible counterpart
  42. EP260128a: LCO optical upper limits
  43. EP260126a: SVOM/VT optical upperlimit
  44. EP260128a: Global MASTER-Net observations report
  45. Fermi GRB 260127A: Global MASTER-Net observations report
  46. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  47. GRB 260127A: Fermi GBM Observation
  48. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  49. GRB 260127A: COLIBRÍ optical observations
  50. GRB 260127A: NOT optical observations
  51. GRB 260127B: Swift ToO observations
  52. EP260126a: Seimei/TriCCS optical upper limit
  53. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  54. GRB 260127B: GOTO candidate optical counterpart
  55. GRB 260127A: SVOM/C-GFT optical observations
  56. Fermi GRB 260127B: Global MASTER-Net observations report
  57. Swift GRB 260127A: Global MASTER-Net observations report
  58. GRB 260127A: LCO optical afterglow discovery
  59. GRB 260125A: Swift-XRT observations
  60. EP260126a: EP-FXT follow-up observation
  61. EP260126a: Optical upper limit with Kinder observations
  62. EP260126a: Liverpool Telescope optical upper limits
  63. EP260126a: Further NOT optical upper limits
  64. EP260126a: COLIBRÍ optical upper limits
  65. EP260126a: NOT optical observations
  66. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  67. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  68. Konus-Wind detection of GRB 260120B
  69. GRB 251222A: SVOM/ECLAIRs refined analysis
  70. GRB 260125A: Swift ToO observations
  71. GRB 260125A: GOTO candidate optical counterpart
  72. Fermi GRB 260125B: Global MASTER-Net observations report
  73. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  74. GRB 260114A: SVOM/VT optical upper limits
  75. GRB 260120A: AstroSat CZTI detection
  76. GRB 260122B: Swift-BAT refined analysis
  77. GRB 260120B: SVOM/GRM observation
  78. GRB 260120A: GECAM-B observation
  79. GRB 260120B: AstroSat CZTI detection
  80. GRB 260114A: Insight-HXMT/HE detection
  81. EP260119a: Assy AZT-20 optical observations
  82. EP260119a: Mondy and SAO RAS optical upper limits
  83. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  84. EP260119a: Xinglong optical upper limit
  85. Fermi GRB 260120C: Global MASTER-Net observations report
  86. GRB 260120B: Swift-BAT refined analysis
  87. EP260116a: COLIBRÍ further observations
  88. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  89. GRB 260120B: Fermi GBM Observation
  90. EP260105a: GTC/HiPERCAM optical observations
  91. GRB 260120B: Swift/UVOT Detection
  92. GRB 260120B: COLIBRÍ optical upper limits
  93. GRB 260120B: SVOM/C-GFT optical counterpart detection
  94. GRB 260101A: 239Alferov CubeSat detection
  95. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  96. EP260119A: Mondy I-Band Observations
  97. GRB 260114A: Swift/UVOT Upper Limits
  98. EP260119a: Liverpool Telescope optical follow-up observations
  99. GRB 251202A: further radio observations with the VLA
  100. Trigger 1442421: Swift detection of HMXB 1A 1118-61

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