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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

38414 results found.

  1. EP260703a: EP-WXT detection of a fast X-ray transient
  2. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  3. GRB 260703A: Fermi GBM Final Localization
  4. GRB 260610B: VLA detection
  5. GRB 260623A: Glowbug gamma-ray detection
  6. GRB 260614B: ATCA Radio Upper Limits
  7. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  8. GRB 260701A: Fermi GBM Final Real-time Localization
  9. Fermi GBM trigger 804552016/260630945 is not a GRB
  10. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  11. EP260628a: EP-FXT follow-up observation
  12. GRB 260629A: Fermi GBM Final Real-time Localization
  13. EP260628a: EP-WXT detection of a fast X-ray transient
  14. GRB 260628A: Fermi GBM Final Real-time Localization
  15. The EP-WXT trigger 01709272671 is likely a flaring star
  16. EP260626a: further Liverpool Telescope optical upper limits
  17. EP260626a: EP-FXT follow-up observation
  18. EP260626a: COLIBRÍ optical upper limit
  19. EP260626a: Liverpool Telescope upper limits
  20. EP260626a: EP-WXT detection of a fast X-ray transient
  21. Konus-Wind detection of GRB 260623B / EP260623a
  22. EP260623a: TNG NIR afterglow detection
  23. GRB 260618A: Fermi GBM Observation
  24. MASS-Cube (GRID 2.0) detection of GRB 260616B
  25. GRB 260619A: SVOM/ECLAIRs refined analysis
  26. EP260623a: Liverpool Telescope optical observations
  27. Fermi GBM trigger 804010507/260624677 is not a GRB
  28. Konus-Wind detection of GRB 260618B
  29. GRB 260624A: Fermi GBM Final Real-time Localization
  30. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  31. GRB 260617A: Glowbug gamma-ray detection of a short burst
  32. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  33. IPN triangulation of GRB 260605A
  34. EP260623a: Optical follow-up observations with Kinder
  35. GRB 260623A: Fermi GBM Final Real-time Localization
  36. EP260623a: SVOM/VT optical observations
  37. EP260623a: TRT optical observations
  38. EP260623a: REM optical/NIR afterglow detection
  39. EP 260623a: COLIBRÍ optical observations
  40. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  41. EP260623a: OSIRIS+/GTC redshift z = 0.703
  42. EP260623a: Einstein Probe detection of an X-ray transient
  43. GRB 260614B: EP-FXT follow-up observation
  44. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  45. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  46. EP260618a: Liverpool Telescope optical observations
  47. GRB 260619A: NOT optical observations
  48. GRB 260618B: LCO optical observations
  49. The EP-WXT trigger 01709271197 is likely a flaring star
  50. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  51. GRB 260618B: Fermi GBM Observation
  52. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 260619A: TRT optical counterpart confirmation
  54. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  55. GRB 260604B: 239Alferov CubeSat detection
  56. GRB 260604A: 239Alferov CubeSat detection
  57. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  58. GRB 260619A: SVOM/VT optical counterpart confirmation
  59. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  60. GRB 260618B: SVOM/VT optical candidate
  61. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  62. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  63. Konus-Wind detection of GRB 260617A
  64. GRB 260616B: AstroSat CZTI detection
  65. GRB 260616A: AstroSat CZTI detection
  66. GRB 260616A: SVOM/GRM observation
  67. EP260618a: OHP/T193 optical observations
  68. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  69. GRB 260619A: Kilonova-Catcher optical upper limit
  70. EP260618a: EP-FXT follow-up observation
  71. EP260618a: LCO optical counterpart confirmation
  72. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  73. EP260618a: COLIBRÍ optical counterpart candidate
  74. GRB 260616A: NuSTAR detection of prompt emission
  75. GRB 260614B: NuSTAR detection of prompt emission
  76. GRB 260619A: SVOM possible detection of a faint burst
  77. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  78. GRB 260618B: Fermi-LAT detection
  79. IPN triangulation of GRB 260617A (short)
  80. GRB 260616A: Insight-HXMT detection
  81. GRB 260618B: Fermi GBM Final Real-time Localization
  82. EP260618a: EP-WXT detection of an X-ray transient
  83. GRB 260610B: AbAO optical observations
  84. EP260616a/GRB 260616B: EP-FXT follow-up observation
  85. GRB 260506B: cubesat Avion detection
  86. GRB 260616C: GECAM-B observation of a burst
  87. GRB 260618A: Fermi GBM Final Real-time Localization
  88. GRB 260617A: Fermi GBM Detection
  89. GRB 260616A: Fermi GBM Observation
  90. GRB 260617A: Fermi GBM Final Real-time Localization
  91. Konus-Wind detection of GRB 260616B/EP260616a
  92. Konus-Wind detection of GRB 260616A
  93. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  94. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  95. GRB 260616A: GECAM-B observation
  96. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  97. GRB 260429A: cubesat Avion detection
  98. GRB260616C: MAXI/GSC detection
  99. GRB 260616A: Fermi-LAT detection
  100. GRB 260610B / AT 2026owq: Liverpool Telescope confirmation of continuing optical rebrightening

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