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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"

32698 results found.

  1. EP260128a: Global MASTER-Net observations report
  2. Fermi GRB 260127A: Global MASTER-Net observations report
  3. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  4. GRB 260127A: Fermi GBM Observation
  5. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  6. GRB 260127A: COLIBRÍ optical observations
  7. GRB 260127A: NOT optical observations
  8. GRB 260127B: Swift ToO observations
  9. EP260126a: Seimei/TriCCS optical upper limit
  10. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  11. GRB 260127B: GOTO candidate optical counterpart
  12. GRB 260127A: SVOM/C-GFT optical observations
  13. Fermi GRB 260127B: Global MASTER-Net observations report
  14. Swift GRB 260127A: Global MASTER-Net observations report
  15. GRB 260127A: LCO optical afterglow discovery
  16. GRB 260125A: Swift-XRT observations
  17. EP260126a: EP-FXT follow-up observation
  18. EP260126a: Optical upper limit with Kinder observations
  19. EP260126a: Liverpool Telescope optical upper limits
  20. EP260126a: Further NOT optical upper limits
  21. EP260126a: COLIBRÍ optical upper limits
  22. EP260126a: NOT optical observations
  23. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  24. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  25. Konus-Wind detection of GRB 260120B
  26. GRB 251222A: SVOM/ECLAIRs refined analysis
  27. GRB 260125A: Swift ToO observations
  28. GRB 260125A: GOTO candidate optical counterpart
  29. Fermi GRB 260125B: Global MASTER-Net observations report
  30. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  31. GRB 260114A: SVOM/VT optical upper limits
  32. GRB 260120A: AstroSat CZTI detection
  33. GRB 260122B: Swift-BAT refined analysis
  34. GRB 260120B: SVOM/GRM observation
  35. GRB 260120A: GECAM-B observation
  36. GRB 260120B: AstroSat CZTI detection
  37. GRB 260114A: Insight-HXMT/HE detection
  38. EP260119a: Assy AZT-20 optical observations
  39. EP260119a: Mondy and SAO RAS optical upper limits
  40. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  41. EP260119a: Xinglong optical upper limit
  42. Fermi GRB 260120C: Global MASTER-Net observations report
  43. GRB 260120B: Swift-BAT refined analysis
  44. EP260116a: COLIBRÍ further observations
  45. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  46. GRB 260120B: Fermi GBM Observation
  47. EP260105a: GTC/HiPERCAM optical observations
  48. GRB 260120B: Swift/UVOT Detection
  49. GRB 260120B: COLIBRÍ optical upper limits
  50. GRB 260120B: SVOM/C-GFT optical counterpart detection
  51. GRB 260101A: 239Alferov CubeSat detection
  52. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  53. EP260119A: Mondy I-Band Observations
  54. GRB 260114A: Swift/UVOT Upper Limits
  55. EP260119a: Liverpool Telescope optical follow-up observations
  56. GRB 251202A: further radio observations with the VLA
  57. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  58. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  59. EP260119a: KAIT optical observations
  60. EP260119a: SVOM/VT optical observation
  61. EP260119a: update of EP-FXT follow-up observation
  62. EP260119a: NOT optical observations
  63. EP260119a: SAO RAS optical observations
  64. EP260116a: COLIBRÍ detection of a fading optical source
  65. GRB 251208D: SVOM/ECLAIRs refined analysis
  66. GRB 251208D: SVOM/ECLAIRs refined analysis
  67. GRB 260117A: Swift-XRT afterglow detection
  68. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  69. EP260119a: Global MASTER-Net observations report
  70. GRB 260115A: AstroSat CZTI detection
  71. EP260119a: LCO optical observations
  72. GRB 260117A: ZTSh optical upper limit
  73. EP260119a: COLIBRÍ optical counterpart candidate
  74. EP260119a: preliminary result from the EP-FXT observation
  75. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  76. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  77. Swift trigger on the HMXB 1A 1118-61
  78. GRB 260117A: SVOM/VT optical candidate
  79. GRB 260117A: SVOM/C-GFT upper limit
  80. GRB 260117A: Swift ToO observations
  81. EP 260116a: COLIBRÍ optical upper limit
  82. GRB 260115A: GECAM-B observation
  83. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  84. EP260116a: Liverpool Telescope upper limits
  85. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  86. EP260116A: 1.3m DFOT optical upper limit
  87. GRB 260114A: VLT/MUSE spectroscopic observations
  88. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  89. EP260116a: Global MASTER-Net observations report
  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. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  94. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  95. Fermi GRB 260115A: Global MASTER-Net observations report
  96. GRB260114A: STEP/T80S optical limits
  97. GRB 251222A: radio detection with the VLA
  98. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  99. Konus-Wind detection of GRB 260114A
  100. GRB 260114A: 6 GHz VLA observations

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