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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"

41718 results found.

  1. GRB 260611B: SVOM/GRM detection
  2. GRB 260614A: Fermi GBM Final Localization
  3. The EP-WXT trigger 01709269488 is likely a flaring star
  4. GRB 260603C: AstroSat CZTI detection
  5. GRB 260610B: further Liverpool Telescope optical observations
  6. GRB 260610B: Fermi GBM Observation
  7. GRB 260610B / AT2026owq: GRANDMA optical observations
  8. GRB 260610B / AT2026owq: further SAO RAS optical observations
  9. EP260605a: COLIBRÍ optical upper limits
  10. GRB 260610b: Liverpool Telescope optical observations
  11. IceCube-260610A: No candidates from the Zwicky Transient Facility
  12. IceCube-260610A: EP-FXT follow-up observation
  13. GRB 260611B: CALET Gamma-Ray Burst Monitor detection
  14. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  15. GRB 260610B / AT2026owq: SVOM/VT optical observations
  16. GRB 260610B / AT2026owq: OASDG optical observations
  17. GRB 260610B: IAC-80 Optical observations
  18. GRB 260610B / AT2026owq: SAO RAS optical observations
  19. GRB 260611B: Fermi GBM Final Real-time Localization
  20. EP260601a: VLT/X-shooter spectroscopic host galaxy redshift z = 1.068
  21. EP260610b: GTC likely spectroscopic redshift z = 1.10
  22. GRB 260610B: optical counterpart shows spectroscopic redshift of z=0.473
  23. The EP-WXT trigger 01709269176 is likely a flaring star
  24. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  25. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  26. GRB 260610B / AT2026owq: Early ATLAS observations
  27. GRB 260610B: TRT optical observation
  28. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  29. GRB 260611A: Fermi GBM Final Real-time Localization
  30. EP260610b: COLIBRÍ optical observations
  31. GRB 260610B: DDOTI optical observations
  32. EP260610b: MAO/AZT-22 optical observations
  33. GRB 260610B: GOTO optical counterpart candidate
  34. EP260610b: NOT optical observation
  35. GRB 260610B: Fermi GBM Final Localization
  36. EP260610b: SVOM/VT optical confirmation with blue color
  37. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  38. GRB 260515A: SOAR optical observations
  39. EP260610b: Gemini North optical counterpart candidate
  40. EP260610a: SVOM/VT optical upper limits
  41. EP260610b: Einstein Probe detection of an X-ray transient
  42. Konus-Wind detection of GRB 260601A
  43. GRB 260610A: Fermi GBM Final Real-time Localization
  44. EP260610a: COLIBRÍ optical upper limits
  45. EP260610a: Einstein Probe detection of a fast X-ray transient
  46. GRB 260609A: Fermi GBM Final Localization
  47. Konus-Wind detection of GRB 260604C
  48. GRB 260608A: Fermi GRB Observation
  49. GRB 260604C: AstroSat CZTI detection
  50. GRB 260604C: SVOM/ECLAIRs refined analysis
  51. GRB 260608A: SVOM/ECLAIRs refined analysis
  52. Konus-Wind detection of GRB 260607B
  53. GRB 260607B: GECAM-B observation
  54. GRB 260608C: Fermi GBM Final Real-time Localization
  55. GRB 260604C: further SAO RAS optical observations
  56. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  57. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  58. GRB 260608B: Fermi GBM Final Localization
  59. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  60. GRB 260604C: SVOM/C-GFT upper limit
  61. GRB 260607B: AstroSat CZTI detection
  62. GRB 260608A: SVOM detection of a burst
  63. GRB 260608A: Fermi GBM Final Real-time Localization
  64. EP260605a: EP-FXT follow-up observation
  65. GRB 260607A: TRT optical observations
  66. GRB 260604C: GRANDMA further observations
  67. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  68. GRB 260604A: SVOM/GRM detection
  69. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  70. GRB 260607B: Fermi GBM Observation
  71. GRB 260607B: Fermi-LAT detection
  72. GRB 260607B: Fermi GBM Final Localization Correction
  73. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  74. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  75. GRB 260607A: Fermi GBM Final Real-time Localization
  76. GRB 260604C: GECAM-B observation
  77. GRB 260604C: 6 GHz VLA observations
  78. GRB 260604C: SAO RAS optical observations
  79. GRB 260604C: GRANDMA observations
  80. GRB 260604B: SVOM/GRM detection
  81. GRB 260605A: Insight-HXMT/HE detection
  82. GRB260603A: SVOM/ECLAIRs refined analysis
  83. EP260605a: Einstein Probe detection of a fast X-ray transient
  84. EP260603a: COLIBRÍ optical upper limit
  85. GRB 260604A: Glowbug gamma-ray detection
  86. GRB 260604C: LCO optical upper limit
  87. GRB 260604C: Liverpool Telescope optical detection
  88. The EP-WXT trigger 01709267001 is likely a flaring star
  89. EP260602d: EP-FXT follow-up observation
  90. EP260602c: EP-FXT follow-up observation
  91. GRB 260601B / EP260601a: AstroSat CZTI detection
  92. GRB 260527A/EP260527a: 6 GHz VLA observations
  93. GRB 260604C: GOTO detections of the optical afterglow
  94. GRB 260604C: Kilonova-Catcher optical afterglow detection
  95. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. The EP-WXT trigger 01709266798 is likely a flaring star
  97. GRB 260604C: Jinshan optical observations
  98. GRB 260604C: Fermi GBM Observation
  99. EP260602d: J-band upper limit with WINTER
  100. EP260602b: J-band upper limit with WINTER

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