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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').
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"

45447 results found.

  1. GRB 260706A: SVOM detection of a burst
  2. GRB 260706A: Fermi GBM Final Real-time Localization
  3. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  4. The EP-WXT trigger 01709274014 is likely a flaring star
  5. IceCube260704A: OHP/T193 optical observations
  6. GRB 260705A: LCO optical upper limits
  7. GRB 260704A: NOT optical upper limits
  8. GRB 260705C: Fermi GBM Final Localization
  9. GRB 260705B: Fermi GBM Final Real-time Localization
  10. Fermi GBM Sub-Threshold Detection of GRB 260705A
  11. GRB 260705A: SVOM detection of a burst
  12. GRB 260704A: EP-FXT follow-up observation
  13. GRB 260629A: SVOM/GRM observation of a short burst
  14. GRB 260629A: GECAM-A observation of a short burst
  15. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  16. GRB 260629A: AstroSat CZTI detection
  17. EP260703a: EP-FXT follow-up observation
  18. GRB 260704A: SVOM detection of a possible GRB
  19. GRB 260703B: Fermi GBM Final Localization
  20. EP260703a: EP-WXT detection of a fast X-ray transient
  21. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  22. Fermi trigger No 804738310: Global MASTER-Net observations report
  23. Fermi GRB 260703A: Global MASTER-Net observations report
  24. GRB 260703A: Fermi GBM Final Localization
  25. GRB 260610B: VLA detection
  26. GRB 260623A: Glowbug gamma-ray detection
  27. GRB 260614B: ATCA Radio Upper Limits
  28. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  29. Fermi trigger No 804552016: Global MASTER-Net observations report
  30. GRB 260701A: Fermi GBM Final Real-time Localization
  31. Fermi GBM trigger 804552016/260630945 is not a GRB
  32. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  33. EP260628a: EP-FXT follow-up observation
  34. GRB 260629A: Fermi GBM Final Real-time Localization
  35. Fermi GRB 260628A: Global MASTER-Net observations report
  36. EP260628a: EP-WXT detection of a fast X-ray transient
  37. GRB 260628A: Fermi GBM Final Real-time Localization
  38. The EP-WXT trigger 01709272671 is likely a flaring star
  39. EP260626a: further Liverpool Telescope optical upper limits
  40. EP260626a: EP-FXT follow-up observation
  41. EP260626a: COLIBRÍ optical upper limit
  42. EP260626a: Liverpool Telescope upper limits
  43. EP260626a: EP-WXT detection of a fast X-ray transient
  44. Konus-Wind detection of GRB 260623B / EP260623a
  45. EP260623a: TNG NIR afterglow detection
  46. GRB 260618A: Fermi GBM Observation
  47. MASS-Cube (GRID 2.0) detection of GRB 260616B
  48. EP260623a: FTW optical and NIR observations
  49. GRB 260619A: SVOM/ECLAIRs refined analysis
  50. EP260623a: Liverpool Telescope optical observations
  51. Fermi GBM trigger 804010507/260624677 is not a GRB
  52. Konus-Wind detection of GRB 260618B
  53. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  54. GRB 260624A: Fermi GBM Final Real-time Localization
  55. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  56. EP260623a: WINTER J-band observations
  57. GRB 260617A: Glowbug gamma-ray detection of a short burst
  58. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  59. IPN triangulation of GRB 260605A
  60. EP260623a: Optical follow-up observations with Kinder
  61. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  62. GRB 260623A: Fermi GBM Final Real-time Localization
  63. EP260623a: SVOM/VT optical observations
  64. EP260623a: TRT optical observations
  65. EP260623a: REM optical/NIR afterglow detection
  66. EP 260623a: COLIBRÍ optical observations
  67. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  68. EP260623a: OSIRIS+/GTC redshift z = 0.703
  69. EP260623a: Las Cumbres discovery of the optical counterpart
  70. EP260623a: Einstein Probe detection of an X-ray transient
  71. GRB 260614B: EP-FXT follow-up observation
  72. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  74. EP260618a: Liverpool Telescope optical observations
  75. GRB 260619A: NOT optical observations
  76. GRB 260618B: LCO optical observations
  77. The EP-WXT trigger 01709271197 is likely a flaring star
  78. EP260618a: JinShan optical observations
  79. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  80. GRB 260618B: Fermi GBM Observation
  81. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  82. GRB 260619A: TRT optical counterpart confirmation
  83. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  84. GRB 260604B: 239Alferov CubeSat detection
  85. GRB 260604A: 239Alferov CubeSat detection
  86. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  87. GRB 260619A: SVOM/VT optical counterpart confirmation
  88. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  89. GRB 260618B: SVOM/VT optical candidate
  90. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  91. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  92. Konus-Wind detection of GRB 260617A
  93. GRB 260616B: AstroSat CZTI detection
  94. GRB 260616A: AstroSat CZTI detection
  95. GRB 260616A: SVOM/GRM observation
  96. EP260618a: OHP/T193 optical observations
  97. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  98. GRB 260619A: Kilonova-Catcher optical upper limit
  99. EP260618a: EP-FXT follow-up observation
  100. EP260618a: LCO optical counterpart confirmation

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