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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"

32550 results found.

  1. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  2. EP260610b: COLIBRÍ optical observations
  3. GRB 260610B: DDOTI optical observations
  4. EP260610b: MAO/AZT-22 optical observations
  5. GRB 260610B: GOTO optical counterpart candidate
  6. EP260610b: NOT optical observation
  7. EP260610b: SVOM/VT optical confirmation with blue color
  8. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  9. GRB 260515A: SOAR optical observations
  10. EP260610b: Gemini North optical counterpart candidate
  11. EP260610a: SVOM/VT optical upper limits
  12. Konus-Wind detection of GRB 260601A
  13. IPN triangulation of GRB 260601A (short/hard)
  14. GRB 260610A: Fermi GBM Final Real-time Localization (duplicate submission)
  15. EP260610a: COLIBRÍ optical upper limits
  16. Konus-Wind detection of GRB 260604C
  17. GRB 260608A: Fermi GRB Observation
  18. GRB 260604C: AstroSat CZTI detection
  19. IPN triangulation of GRB 260601B / EP260601a
  20. GRB 260604C: SVOM/ECLAIRs refined analysis
  21. GRB 260608A: SVOM/ECLAIRs refined analysis
  22. Konus-Wind detection of GRB 260607B
  23. GRB 260607B: GECAM-B observation
  24. GRB 260608C: Fermi GBM Final Real-time Localization (duplicate submission)
  25. GRB 260604C: further SAO RAS optical observations
  26. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  27. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  28. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  29. GRB 260604C: SVOM/C-GFT upper limit
  30. GRB 260607B: AstroSat CZTI detection
  31. GRB 260608A: SVOM detection of a burst
  32. GRB 260608A: Fermi GBM Final Real-time Localization (duplicate submission)
  33. EP260605a: EP-FXT follow-up observation
  34. GRB 260607A: TRT optical observations
  35. GRB 260604C: GRANDMA further observations
  36. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  37. GRB 260604A: SVOM/GRM detection
  38. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  39. GRB 260607B: Fermi GBM Observation
  40. GRB 260607B: Fermi-LAT detection
  41. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  42. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  43. GRB 260607A: Fermi GBM Final Real-time Localization (duplicate submission)
  44. GRB 260604C: GECAM-B observation
  45. GRB 260604C: 6 GHz VLA observations
  46. GRB 260604C: SAO RAS optical observations
  47. GRB 260604C: GRANDMA observations
  48. GRB 260604B: SVOM/GRM detection
  49. GRB260603A: SVOM/ECLAIRs refined analysis
  50. EP260603a: COLIBRÍ optical upper limit
  51. GRB 260604A: Glowbug gamma-ray detection
  52. GRB 260604C: LCO optical upper limit
  53. GRB 260604C: Liverpool Telescope optical detection
  54. EP260602d: EP-FXT follow-up observation
  55. EP260602c: EP-FXT follow-up observation
  56. GRB 260601B / EP260601a: AstroSat CZTI detection
  57. GRB 260527A/EP260527a: 6 GHz VLA observations
  58. GRB 260604C: GOTO detections of the optical afterglow
  59. GRB 260604C: Correction to GCN 44828
  60. GRB 260604C: Kilonova-Catcher optical afterglow detection
  61. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  62. GRB 260604C: Jinshan optical observations
  63. GRB 260604C: Fermi GBM Observation
  64. EP260602d: J-band upper limit with WINTER
  65. EP260602b: J-band upper limit with WINTER
  66. GRB 260604C: LAST detection of optical counterpart candidate
  67. Fermi GRB 260604C: Global MASTER-Net observations report
  68. Fermi GRB 260604C: Global MASTER-Net observations report
  69. GRB 260604C: SVOM detection of a long burst
  70. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  71. GRB 260603A: NOT optical observations
  72. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  73. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  74. EP260602a: EP-FXT follow-up observation
  75. EP260603a: Global MASTER-Net observations report
  76. EP260602d: Optical Upper limits with kinder observations
  77. EP260602b: Liverpool Telescope observations
  78. EP260602a: Liverpool Telescope optical upper limits
  79. EP260602b: Liverpool Telescope and LCO observations
  80. EP260602a: GTC and Liverpool Telescope optical observations
  81. Konus-Wind detection of GRB 260601B/EP260601a
  82. GRB 260603A: EP-FXT follow-up observation
  83. EP260601a/GRB 260601B: EP-FXT follow-up observation
  84. GRB 260601B / EP260601a: Mondy optical upper limit
  85. EP260602b: EP-FXT follow-up observation
  86. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  87. GRB 260603A: Kilonova-Catcher optical upper limit
  88. GRB 260603A: SVOM/VT optical observations
  89. EP260602a: NOT NIR J-band observations
  90. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  91. EP260602d: Einstein Probe detection of a fast X-ray transient
  92. EP260602a: SVOM/VT optical magnitudes correction
  93. GRB 260601A: SVOM/GRM observation of a short burst
  94. EP260602c: Einstein Probe detection of a fast X-ray transient
  95. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  96. EP260602a: COLIBRÍ optical observations
  97. GRB260601B/EP260601a: NOT near-infrared observations
  98. EP260602b: Einstein Probe detection of a fast X-ray transient
  99. GRB 260601B/EP260601a: Insight-HXMT detection
  100. Fermi GRB 260602B: Global MASTER-Net observations report

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