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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"

27571 results found.

  1. The EP-WXT trigger 01709274141 is likely a flaring star
  2. GRB 260706A: Fermi GBM Observation
  3. GRB 260706A: SVOM detection of a burst
  4. GRB 260706A: Fermi GBM Final Real-time Localization
  5. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  6. The EP-WXT trigger 01709274014 is likely a flaring star
  7. IceCube260704A: OHP/T193 optical observations
  8. GRB 260705A: LCO optical upper limits
  9. GRB 260704A: NOT optical upper limits
  10. GRB 260705C: Fermi GBM Final Localization
  11. GRB 260705B: Fermi GBM Final Real-time Localization
  12. Fermi GBM Sub-Threshold Detection of GRB 260705A
  13. GRB 260705A: SVOM detection of a burst
  14. GRB 260704A: EP-FXT follow-up observation
  15. GRB 260704A: SVOM detection of a possible GRB
  16. GRB 260703B: Fermi GBM Final Localization
  17. Fermi trigger No 804738310: Global MASTER-Net observations report
  18. Fermi GRB 260703A: Global MASTER-Net observations report
  19. GRB 260703A: Fermi GBM Final Localization
  20. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  21. Fermi trigger No 804552016: Global MASTER-Net observations report
  22. GRB 260701A: Fermi GBM Final Real-time Localization
  23. Fermi GBM trigger 804552016/260630945 is not a GRB
  24. GRB 260629A: Fermi GBM Final Real-time Localization
  25. Fermi GRB 260628A: Global MASTER-Net observations report
  26. GRB 260628A: Fermi GBM Final Real-time Localization
  27. The EP-WXT trigger 01709272671 is likely a flaring star
  28. EP260626a: further Liverpool Telescope optical upper limits
  29. EP260626a: COLIBRÍ optical upper limit
  30. EP260623a: TNG NIR afterglow detection
  31. GRB 260618A: Fermi GBM Observation
  32. EP260623a: FTW optical and NIR observations
  33. EP260623a: Liverpool Telescope optical observations
  34. Fermi GBM trigger 804010507/260624677 is not a GRB
  35. GRB 260624A: Fermi GBM Final Real-time Localization
  36. EP260623a: WINTER J-band observations
  37. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  38. GRB 260623A: Fermi GBM Final Real-time Localization
  39. EP260623a: SVOM/VT optical observations
  40. EP260623a: TRT optical observations
  41. EP260623a: REM optical/NIR afterglow detection
  42. EP 260623a: COLIBRÍ optical observations
  43. EP260623a: OSIRIS+/GTC redshift z = 0.703
  44. EP260623a: Las Cumbres discovery of the optical counterpart
  45. GRB 260614B: EP-FXT follow-up observation
  46. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  47. EP260618a: Liverpool Telescope optical observations
  48. GRB 260619A: NOT optical observations
  49. GRB 260618B: LCO optical observations
  50. The EP-WXT trigger 01709271197 is likely a flaring star
  51. EP260618a: JinShan optical observations
  52. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  53. GRB 260618B: Fermi GBM Observation
  54. GRB 260619A: TRT optical counterpart confirmation
  55. GRB 260619A: SVOM/VT optical counterpart confirmation
  56. GRB 260618B: SVOM/VT optical candidate
  57. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  58. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  59. Konus-Wind detection of GRB 260617A
  60. EP260618a: OHP/T193 optical observations
  61. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  62. EP260618a: LCO optical counterpart confirmation
  63. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  64. EP260618a: COLIBRÍ optical counterpart candidate
  65. GRB 260619A: SVOM possible detection of a faint burst
  66. GRB 260618B: Fermi-LAT detection
  67. IPN triangulation of GRB 260617A (short)
  68. GRB 260618B: Fermi GBM Final Real-time Localization
  69. GRB 260610B: AbAO optical observations
  70. GRB 260618A: Fermi GBM Final Real-time Localization
  71. GRB 260617A: Fermi GBM Detection
  72. GRB 260616A: Fermi GBM Observation
  73. GRB 260617A: Fermi GBM Final Real-time Localization
  74. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  75. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  76. GRB 260616A: Fermi-LAT detection
  77. GRB 260610B / AT 2026owq: Liverpool Telescope confirmation of continuing optical rebrightening
  78. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  79. The EP-WXT trigger 01709270148 is likely a flaring star
  80. GRB 260616B: Fermi GBM Detection
  81. GRB 260616B: BALROG localization (Fermi Trigger 803286321 / GRB 260616295)
  82. The EP-WXT trigger 01709269893 is likely a flaring star
  83. GRB 260616A: BALROG localization (Fermi Trigger 803272919 / GRB 260616140)
  84. GRB 260616A: Fermi GBM Final Real-time Localization
  85. GRB 260614B: SVOM/ECLAIRs refined analysis
  86. GRB 260614B: SVOM/VT optical afterglow confirmation
  87. GRB 260614B: Fermi GBM Observation
  88. GRB 260614B: SVOM/VT optical candidate from VHF data
  89. GRB 260614B: SVOM detection of a burst
  90. GRB 260614B: Fermi GBM Final Real-time Localization
  91. GRB 260614A: Fermi GBM Final Localization
  92. The EP-WXT trigger 01709269488 is likely a flaring star
  93. GRB 260610B: further Liverpool Telescope optical observations
  94. GRB 260610B: Fermi GBM Observation
  95. GRB 260610B / AT2026owq: GRANDMA optical observations
  96. EP260605a: COLIBRÍ optical upper limits
  97. GRB 260610b: Liverpool Telescope optical observations
  98. EP260610b: Liverpool Telescope optical upper limits
  99. IceCube-260610A: EP-FXT follow-up observation
  100. GRB 260611B: CALET Gamma-Ray Burst Monitor detection

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