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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"

27009 results found.

  1. EP261103a: NOT optical counterpart candidate
  2. EP261103a: Einstein Probe detection of an X-ray transient
  3. GRB 261029A: VST/OmegaCAM detection of the optical afterglow at 3 days
  4. GRB 261029A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation
  5. GRB 261103A: LCO optical upper limits
  6. GRB 261103A: SVOM/ECLAIRs detection of a burst through on-ground search
  7. EP-WXT trigger 01709322206: confirmation of a stellar flare by BOOTES-5
  8. GRB 261029A: SAO RAS optical observations
  9. The EP-WXT trigger 01709322206 is likely a flaring star
  10. EP261015a/SN 2026ahoa: VLT/FORS2 discovery of a pre-peak type Ic-BL supernova at a tentative spectroscopic redshift z=0.31
  11. GRB 261102A: Fermi GBM Detection
  12. GRB 261029C: AstroSat CZTI detection of a short burst
  13. GRB 261102A: Fermi GBM Final Real-time Localization
  14. GRB 261101B: BALROG localization (Fermi Trigger 815240277 / GRB 261101651)
  15. GRB 261101B: Fermi GBM Final Real-time Localization
  16. EP261030a: EP-FXT follow-up observation
  17. GRB 261101A: Fermi GBM Final Real-time Localization
  18. EP261030a: Einstein Probe detection of a fast X-ray transient
  19. GRB 261030A: Fermi GBM Detection
  20. GRB 261030B: Fermi GBM Final Real-time Localization
  21. GRB 261029A: SVOM/ECLAIRs refined analysis
  22. The EP-WXT trigger 01709321980: KAIT confirmation of a stellar flare
  23. GRB 261030A: BALROG localization (Fermi Trigger 815070447 / GRB 261030686)
  24. GRB 261030A: Fermi GBM Final Real-time Localization
  25. GRB 261029A / AT 2026ahaw: Optical upper limits from the PKU 60cm Telescope
  26. GRB 261029A: Glowbug gamma-ray detection
  27. GRB 261024D: SVOM/GRM observation
  28. GRB 261026A: Mondy, SAO RAS and Terskol optical observations
  29. GRB 261029A : SVOM/GWAC-F60 observations
  30. GRB 261029A: GECAM-B detection of a bright burst
  31. EP-WXT trigger 01709321980: confirmation of a stellar flare by BOOTES-5
  32. The EP-WXT trigger 01709321980 is likely a flaring star
  33. GRB 261029A: ULL-ASTRO-MASTER observations with LCO 1-m telescope at Siding Spring Observatory
  34. GRB 261029A: Liverpool Telescope observations
  35. GRB 261029A: NuSTAR detection of bright prompt emission
  36. GRB 261029A: Optical detection with 60cm Panzhihua Telescope
  37. GRB 261029A: Fermi GBM Observation
  38. GRB 261029A: SVOM/GRM observation of a bright burst
  39. GRB 261029A: CALET Gamma-Ray Burst Monitor detection
  40. IPN triangulation of GRB 261024D
  41. GRB261029A: Infrared fading detected with MDM/MIRAGE
  42. GRB 261029A: SVOM/VT optical observation
  43. GRB 261029B : AstroSat CZTI detection
  44. GRB 261029A : AstroSat CZTI detection
  45. GRB 261029A: SVOM/C-GFT optical observations
  46. EP261010a: Xinglong optical follow-up
  47. GRB 261029A: EP-FXT follow-up observation
  48. GRB 261029A: Fermi-LAT detection
  49. GRB 261029A: LCO optical observations (correction to GCN 46082)
  50. GRB 261029A: SVOM/COLIBRÍ (FM-GFT) optical observations
  51. GRB 261029A: LCO optical observations
  52. GRB 261029A: NOT imaging and spectroscopic redshift z = 3.27
  53. GRB261029A: Early infrared detection with MDM/MIRAGE
  54. GRB 261029A: KAIT optical observations
  55. GRB 261029A: TRT optical observations
  56. EP261006a / AT 2026aetp: Xinglong 2.16-m optical follow-up
  57. EP261025a: EP-FXT follow-up observations
  58. GRB 261029B: Fermi GBM Final Real-time Localization
  59. GRB 261028B / MAXI J1609-487: MAXI GSC detection
  60. GRB 261029A: GOTO optical counterpart candidate
  61. GRB 261029A: SVOM detection of a burst
  62. GRB 261029A: Fermi GBM Final Real-time Localization
  63. GRB 261021A: Glowbug gamma-ray detection
  64. GRB 261028A: Fermi GBM Final Localization
  65. GRB 261026A: SVOM/ECLAIRs refined analysis
  66. GRB 261024C: GECAM-B observation
  67. GRB 261026B: AstroSat CZTI detection
  68. GRB 261024D: Insight-HXMT/HE detection
  69. GRB261026A: Infrared detection with MDM/MIRAGE
  70. GRB 261026A: SVOM/VT optical blue bump
  71. GRB 261026A: SAO RAS optical observations
  72. GRB 261024D: GECAM-B observation
  73. The EP-WXT trigger 01709321750 is likely a flaring star
  74. GRB 261026A: EP-FXT follow-up observation
  75. GRB 261024A: SVOM/GRM observation
  76. GRB 261026A: Upper Limit with 60cm Panzhihua Telescope
  77. GRB 261026A: OHP/T120 optical imaging
  78. GRB 261024D: Glowbug gamma-ray detection
  79. GRB 261026B: NuSTAR detection of prompt emission
  80. GRB 261024D: NuSTAR detection of prompt emission
  81. GRB 261024C: NuSTAR detection of prompt emission
  82. GRB 261026A: Ondrejov D50 optical limit
  83. GRB 261026A: ULL-ASTRO-MASTER optical detection with LCO 40-cm telescope at Haleakalā Observatory
  84. GRB 261026A: J-band observations by the SYSU 80cm infrared telescope
  85. GRB 261026A: SVOM/VT optical observations
  86. IPN triangulation of GRB 260730B
  87. GRB 261026C: Fermi GBM Final Real-time Localization
  88. GRB 261020A: Insight-HXMT/HE detection
  89. GRB 261026A: WINTER J-band observations
  90. GRB 261024D: AstroSat CZTI detection of a long burst
  91. GRB 261024C: AstroSat CZTI detection of a long burst
  92. GRB 261019A: GECAM-B observation
  93. GRB 261019A: SVOM/GRM observation
  94. GRB 261026A: SVOM/VT optical observation from VHF data
  95. GRB 261026A: KAIT optical observations
  96. GRB 261026B: Fermi GBM Final Real-time Localization
  97. GRB 261024A: NuSTAR detection of prompt emission
  98. GRB 261026A: SVOM detection of a burst
  99. GRB 261025B: Fermi GBM Final Real-time Localization
  100. EP261025a: J-band upper limit with WINTER

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