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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

15247 results found.

  1. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 260705A: SVOM/ECLAIRs refined analysis
  3. GRB 260706A: SVOM detection of a burst
  4. The EP-WXT trigger 01709274014 is likely a flaring star
  5. GRB 260704A: NOT optical upper limits
  6. GRB 260705A: SVOM detection of a burst
  7. GRB 260629A: SVOM/GRM observation of a short burst
  8. GRB 260629A: GECAM-A observation of a short burst
  9. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  10. GRB 260629A: AstroSat CZTI detection
  11. GRB 260704A: SVOM detection of a possible GRB
  12. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  13. EP260626a: further Liverpool Telescope optical upper limits
  14. EP260626a: COLIBRÍ optical upper limit
  15. Konus-Wind detection of GRB 260623B / EP260623a
  16. GRB 260618A: Fermi GBM Observation
  17. GRB 260619A: SVOM/ECLAIRs refined analysis
  18. EP260623a: Liverpool Telescope optical observations
  19. Konus-Wind detection of GRB 260618B
  20. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  21. EP260623a: Optical follow-up observations with Kinder
  22. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  23. EP 260623a: COLIBRÍ optical observations
  24. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  25. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  26. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  27. EP260618a: Liverpool Telescope optical observations
  28. GRB 260619A: NOT optical observations
  29. EP260618a: JinShan optical observations
  30. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  31. GRB 260618B: Fermi GBM Observation
  32. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  33. GRB 260619A: TRT optical counterpart confirmation
  34. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  35. GRB 260604B: 239Alferov CubeSat detection
  36. GRB 260604A: 239Alferov CubeSat detection
  37. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  38. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  39. Konus-Wind detection of GRB 260617A
  40. GRB 260616B: AstroSat CZTI detection
  41. GRB 260616A: AstroSat CZTI detection
  42. GRB 260616A: SVOM/GRM observation
  43. EP260618a: LCO optical counterpart confirmation
  44. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  45. GRB 260619A: SVOM possible detection of a faint burst
  46. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 260618B: Fermi-LAT detection
  48. GRB 260610B/AT 2026owq: FTW optical and NIR observations
  49. GRB 260616A: Insight-HXMT detection
  50. EP260618a: EP-WXT detection of an X-ray transient
  51. GRB 260506B: cubesat Avion detection
  52. GRB 260616C: GECAM-B observation of a burst
  53. GRB 260617A: Fermi GBM Detection
  54. Konus-Wind detection of GRB 260616B/EP260616a
  55. Konus-Wind detection of GRB 260616A
  56. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  57. GRB 260616A: GECAM-B observation
  58. GRB 260429A: cubesat Avion detection
  59. GRB 260616A: Fermi-LAT detection
  60. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  61. GRB 260614A: AstroSat CZTI detection
  62. GRB 260614B: SVOM/ECLAIRs refined analysis
  63. GRB 260614B: GECAM-B observation
  64. GRB 260610B: SVOM/GRM observation
  65. GRB 260614B: Fermi GBM Observation
  66. GRB 260614A: GECAM-B observation
  67. GRB 260614B: SVOM detection of a burst
  68. GRB 260611B: SVOM/GRM detection
  69. GRB 260603C: AstroSat CZTI detection
  70. GRB 260610B: further Liverpool Telescope optical observations
  71. GRB 260610B: Fermi GBM Observation
  72. GRB 260610B / AT2026owq: GRANDMA optical observations
  73. GRB 260610b: Liverpool Telescope optical observations
  74. IceCube-260610A: No candidates from the Zwicky Transient Facility
  75. GRB 260611B: CALET Gamma-Ray Burst Monitor detection
  76. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  77. GRB 260610B / AT2026owq: OASDG optical observations
  78. GRB 260610B: optical counterpart shows spectroscopic redshift of z=0.473
  79. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  80. GRB 260610B / AT2026owq: Early ATLAS observations
  81. GRB 260610B: TRT optical observation
  82. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  83. EP260610b: COLIBRÍ optical observations
  84. GRB 260610B: DDOTI optical observations
  85. EP260610b: NOT optical observation
  86. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  87. GRB 260515A: SOAR optical observations
  88. Konus-Wind detection of GRB 260601A
  89. Konus-Wind detection of GRB 260604C
  90. GRB 260608A: Fermi GRB Observation
  91. GRB 260604C: AstroSat CZTI detection
  92. GRB 260604C: SVOM/ECLAIRs refined analysis
  93. GRB 260608A: SVOM/ECLAIRs refined analysis
  94. Konus-Wind detection of GRB 260607B
  95. GRB 260607B: GECAM-B observation
  96. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  97. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  98. GRB 260607B: AstroSat CZTI detection
  99. GRB 260608A: SVOM detection of a burst
  100. GRB 260607A: TRT optical observations

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