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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"

32686 results found.

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

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