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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"

32689 results found.

  1. EP260126a: Seimei/TriCCS optical upper limit
  2. GRB 260127A : MITSuME Akeno optical afterglow candidate detection
  3. GRB 260127B: GOTO candidate optical counterpart
  4. GRB 260127A: SVOM/C-GFT optical observations
  5. Fermi GRB 260127B: Global MASTER-Net observations report
  6. Swift GRB 260127A: Global MASTER-Net observations report
  7. GRB 260127A: LCO optical afterglow discovery
  8. GRB 260125A: Swift-XRT observations
  9. EP260126a: EP-FXT follow-up observation
  10. EP260126a: Optical upper limit with Kinder observations
  11. EP260126a: Liverpool Telescope optical upper limits
  12. EP260126a: Further NOT optical upper limits
  13. EP260126a: COLIBRÍ optical upper limits
  14. EP260126a: NOT optical observations
  15. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  16. GRB 260125A: NOT optical observations on GOTO26acv / AT 2026bjf
  17. Konus-Wind detection of GRB 260120B
  18. GRB 251222A: SVOM/ECLAIRs refined analysis
  19. GRB 260125A: Swift ToO observations
  20. GRB 260125A: GOTO candidate optical counterpart
  21. Fermi GRB 260125B: Global MASTER-Net observations report
  22. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  23. GRB 260114A: SVOM/VT optical upper limits
  24. GRB 260120A: AstroSat CZTI detection
  25. GRB 260122B: Swift-BAT refined analysis
  26. GRB 260120B: SVOM/GRM observation
  27. GRB 260120A: GECAM-B observation
  28. GRB 260120B: AstroSat CZTI detection
  29. GRB 260114A: Insight-HXMT/HE detection
  30. EP260119a: Assy AZT-20 optical observations
  31. EP260119a: Mondy and SAO RAS optical upper limits
  32. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  33. EP260119a: Xinglong optical upper limit
  34. Fermi GRB 260120C: Global MASTER-Net observations report
  35. GRB 260120B: Swift-BAT refined analysis
  36. EP260116a: COLIBRÍ further observations
  37. GRB 251122A / EP251122a: VLT/X-shooter host redshift z = 1.765
  38. GRB 260120B: Fermi GBM Observation
  39. EP260105a: GTC/HiPERCAM optical observations
  40. GRB 260120B: Swift/UVOT Detection
  41. GRB 260120B: COLIBRÍ optical upper limits
  42. GRB 260120B: SVOM/C-GFT optical counterpart detection
  43. GRB 260101A: 239Alferov CubeSat detection
  44. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  45. EP260119A: Mondy I-Band Observations
  46. GRB 260114A: Swift/UVOT Upper Limits
  47. EP260119a: Liverpool Telescope optical follow-up observations
  48. GRB 251202A: further radio observations with the VLA
  49. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  50. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  51. EP260119a: KAIT optical observations
  52. EP260119a: SVOM/VT optical observation
  53. EP260119a: update of EP-FXT follow-up observation
  54. EP260119a: NOT optical observations
  55. EP260119a: SAO RAS optical observations
  56. EP260116a: COLIBRÍ detection of a fading optical source
  57. GRB 251208D: SVOM/ECLAIRs refined analysis
  58. GRB 251208D: SVOM/ECLAIRs refined analysis
  59. GRB 260117A: Swift-XRT afterglow detection
  60. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  61. EP260119a: Global MASTER-Net observations report
  62. GRB 260115A: AstroSat CZTI detection
  63. EP260119a: LCO optical observations
  64. GRB 260117A: ZTSh optical upper limit
  65. EP260119a: COLIBRÍ optical counterpart candidate
  66. EP260119a: preliminary result from the EP-FXT observation
  67. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  68. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  69. Swift trigger on the HMXB 1A 1118-61
  70. GRB 260117A: SVOM/VT optical candidate
  71. GRB 260117A: SVOM/C-GFT upper limit
  72. GRB 260117A: Swift ToO observations
  73. EP 260116a: COLIBRÍ optical upper limit
  74. GRB 260115A: GECAM-B observation
  75. FRB 20251229A: COLIBRÍ further inspection of the updated localization
  76. EP260116a: Liverpool Telescope upper limits
  77. FRB 20251229A: Updated CHIME/FRB Baseband Localization of FRB 20251229A
  78. EP260116A: 1.3m DFOT optical upper limit
  79. GRB 260114A: VLT/MUSE spectroscopic observations
  80. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  81. EP260116a: Global MASTER-Net observations report
  82. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  83. EP260116a: Xinglong optical upper limit
  84. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  85. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  86. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  87. Fermi GRB 260115A: Global MASTER-Net observations report
  88. GRB260114A: STEP/T80S optical limits
  89. GRB 251222A: radio detection with the VLA
  90. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  91. Konus-Wind detection of GRB 260114A
  92. GRB 260114A: 6 GHz VLA observations
  93. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  94. GRB 260114A : MITSuME Akeno optical upper limits
  95. GRB 260114A: COLIBRÍ optical upper limits
  96. GRB 260114A: TNG NIR upper limit
  97. GRB 260114A: NOT optical observations
  98. Konus-Wind detection of GRB 251230A / EP251230a
  99. GRB 260114A: SVOM/GRM observation of a short burst
  100. Swift GRB 260114A: Global MASTER-Net observations report

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