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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"

35996 results found.

  1. GRB 260610B: SVOM/GRM observation
  2. GRB 260614B: SVOM/VT optical afterglow confirmation
  3. GRB 260614B: Fermi GBM Observation
  4. GRB 260610B: ALMA detection
  5. GRB 260614A: GECAM-B observation
  6. GRB 260614B: SVOM/VT optical candidate from VHF data
  7. GRB 260614B: SVOM detection of a burst
  8. GRB 260614B: Fermi GBM Final Real-time Localization
  9. GRB 260611B: SVOM/GRM detection
  10. GRB 260614A: Fermi GBM Final Localization
  11. GRB 260603C: AstroSat CZTI detection
  12. GRB 260610B: further Liverpool Telescope optical observations
  13. GRB 260610B: Fermi GBM Observation
  14. GRB 260610B / AT2026owq: GRANDMA optical observations
  15. GRB 260610B / AT2026owq: further SAO RAS optical observations
  16. GRB 260610b: Liverpool Telescope optical observations
  17. GRB 260611B: CALET Gamma-Ray Burst Monitor detection
  18. GRB 260610B / AT2026owq: SVOM/VT optical observations
  19. GRB 260610B / AT2026owq: OASDG optical observations
  20. GRB 260610B: IAC-80 Optical observations
  21. GRB 260610B / AT2026owq: SAO RAS optical observations
  22. GRB 260611B: Fermi GBM Final Real-time Localization
  23. EP260601a: VLT/X-shooter spectroscopic host galaxy redshift z = 1.068
  24. GRB 260610B: optical counterpart shows spectroscopic redshift of z=0.473
  25. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  26. GRB 260610B / AT2026owq: Early ATLAS observations
  27. GRB 260610B: TRT optical observation
  28. GRB 260611A: Fermi GBM Final Real-time Localization
  29. GRB 260610B: DDOTI optical observations
  30. GRB 260610B: GOTO optical counterpart candidate
  31. GRB 260610B: Fermi GBM Final Localization
  32. GRB 260515A: SOAR optical observations
  33. Konus-Wind detection of GRB 260601A
  34. IPN triangulation of GRB 260601A (short/hard)
  35. GRB 260610A: Fermi GBM Final Real-time Localization (duplicate submission)
  36. GRB 260610A: Fermi GBM Final Real-time Localization
  37. GRB 260609A: Fermi GBM Final Localization
  38. Konus-Wind detection of GRB 260604C
  39. GRB 260608A: Fermi GRB Observation
  40. GRB 260604C: AstroSat CZTI detection
  41. IPN triangulation of GRB 260601B / EP260601a
  42. GRB 260604C: SVOM/ECLAIRs refined analysis
  43. GRB 260608A: SVOM/ECLAIRs refined analysis
  44. Konus-Wind detection of GRB 260607B
  45. GRB 260607B: GECAM-B observation
  46. GRB 260608C: Fermi GBM Final Real-time Localization (duplicate submission)
  47. GRB 260608C: Fermi GBM Final Real-time Localization
  48. GRB 260604C: further SAO RAS optical observations
  49. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  50. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  51. GRB 260608B: Fermi GBM Final Localization
  52. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  53. GRB 260604C: SVOM/C-GFT upper limit
  54. GRB 260607B: AstroSat CZTI detection
  55. GRB 260608A: SVOM detection of a burst
  56. GRB 260608A: Fermi GBM Final Real-time Localization (duplicate submission)
  57. GRB 260608A: Fermi GBM Final Real-time Localization
  58. GRB 260607A: TRT optical observations
  59. GRB 260604C: GRANDMA further observations
  60. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  61. GRB 260604A: SVOM/GRM detection
  62. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  63. GRB 260607B: Fermi GBM Observation
  64. GRB 260607B: Fermi-LAT detection
  65. GRB 260607B: Fermi GBM Final Localization Correction
  66. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  67. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  68. GRB 260607A: Fermi GBM Final Real-time Localization (duplicate submission)
  69. GRB 260607A: Fermi GBM Final Real-time Localization
  70. GRB 260604C: GECAM-B observation
  71. GRB 260604C: 6 GHz VLA observations
  72. GRB 260604C: SAO RAS optical observations
  73. GRB 260604C: GRANDMA observations
  74. GRB 260604B: SVOM/GRM detection
  75. GRB 260605A: Insight-HXMT/HE detection
  76. GRB260603A: SVOM/ECLAIRs refined analysis
  77. GRB 260604A: Glowbug gamma-ray detection
  78. GRB 260604C: LCO optical upper limit
  79. GRB 260604C: Liverpool Telescope optical detection
  80. GRB 260601B / EP260601a: AstroSat CZTI detection
  81. GRB 260527A/EP260527a: 6 GHz VLA observations
  82. GRB 260604C: GOTO detections of the optical afterglow
  83. GRB 260604C: Correction to GCN 44828
  84. GRB 260604C: Kilonova-Catcher optical afterglow detection
  85. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  86. GRB 260604C: Jinshan optical observations
  87. GRB 260604C: Fermi GBM Observation
  88. GRB 260604C: LAST detection of optical counterpart candidate
  89. GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
  90. Fermi GRB 260604C: Global MASTER-Net observations report
  91. Fermi GRB 260604C: Global MASTER-Net observations report
  92. GRB 260604C: SVOM detection of a long burst
  93. GRB 260604C: Fermi GBM Final Real-time Localization
  94. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  95. GRB 260603A: NOT optical observations
  96. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  97. GRB 260604B: Fermi GBM Final Real-time Localization
  98. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  99. GRB 260604A: Fermi GBM Final Real-time Localization
  100. GRB 260603B: Fermi GBM Final Localization

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