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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"

43681 results found.

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

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