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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"

36180 results found.

  1. GRB 251205A: Swift-XRT refined Analysis
  2. GRB 251205A: Swift/UVOT Detection
  3. GRB 251205A: Liverpool Telescope optical follow-up observations
  4. GRB 251203C: Swift/UVOT Upper Limit
  5. Konus-Wind detection of GRB 251118A
  6. GRB 251205A: Zeiss-1000 Koshka observatory optical observations
  7. GRB 251205A: COLIBRÍ optical observations
  8. GRB 251205A: GOTO optical afterglow detection
  9. GRB 251205A: NOT optical observations
  10. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  11. GRB 251205A: Enhanced Swift-XRT position
  12. Swift GRB 251205A : MASTER OT detection with host galaxy
  13. GRB 251205A: Swift detection of a burst with an optical afterglow
  14. GRB 251126B: Fermi GBM Final Localization
  15. GRB 251203A: Insight-HXMT/HE detection
  16. GRB 251203C: SVOM/ECLAIRs refined analysis
  17. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  18. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  19. GRB 251202A: SVOM/GRM observation
  20. GRB 251203A: GECAM-B observation of a burst
  21. GRB 251203A: SVOM/GRM observation
  22. GRB 251201B: SALT spectroscopic redshift z = 1.599
  23. GRB 251203C: J-band observations with WINTER
  24. GRB 251129B: Glowbug gamma-ray detection of a short burst
  25. GRB 251203A: AstroSat CZTI detection
  26. Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
  27. GRB 251203C: LCO optical afterglow confirmation
  28. GRB 251203C: SVOM/VT optical counterpart
  29. GRB 251203C: EP-FXT follow-up observation
  30. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  31. GRB 251129B: GECAM-B observation of a burst
  32. GRB 251203B: Swift-XRT observations
  33. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  34. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  35. GRB 251203C: LCO optical upper limits
  36. GRB 251203B: LCO optical upper limits
  37. GRB 251203B: SVOM/VT optical observation
  38. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  39. GRB 251203C: SVOM detection of a burst
  40. GRB 251203B: SVOM detection of a burst
  41. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  42. GRB 251201B: Insight-HXMT/HE detection
  43. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  44. GRB 251203A: Fermi GBM Final Real-time Localization
  45. EP251202a / GRB251202A: AstroSat CZTI detection
  46. GRB 251202A / EP251202a: SVOM/VT optical observation
  47. GRB 251201B: Fermi GBM Observation
  48. EP251202a/GRB 251202A: KAIT optical observations
  49. Fermi GRB 251202B: Global MASTER-Net observations report
  50. GRB 251202B: Fermi GBM Final Real-time Localization
  51. IPN triangulation of GRB 251129B (short/hard)
  52. GRB251129A/EP251129a: Swift UVOT detection
  53. GRB 251129B: AstroSat CZTI detection
  54. GRB 251202A: Fermi GBM Observation
  55. GRB 251202A: Swift/UVOT Detection
  56. GRB 251201B: Kilonova-Catcher optical afterglow detection
  57. GRB 251201B: Swift/UVOT Detection
  58. GRB 251130B: Glowbug gamma-ray detection
  59. GRB 251201B: GECAM-B observation of a long burst
  60. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  61. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  62. GRB 251202A: GOTO optical afterglow detection
  63. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  64. GRB 251201A: GECAM-B observation of a burst
  65. GRB 251126A: SAO RAS optical marginal detection
  66. GRB 251202A: Swift-XRT afterglow detection
  67. EP251129a/GRB 251129A: NOWT Detection
  68. GRB 251126A: SVOM/VT optical observation
  69. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  70. Fermi GRB 251202A: Global MASTER-Net observations report
  71. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  72. GRB 251201B: Swift-XRT refined Analysis
  73. GRB 251202A: Fermi GBM Final Real-time Localization
  74. GRB 251201A: SVOM/GRM observation of a burst
  75. GRB 251201B: SVOM/VT optical fading
  76. Swift GRB 251201B : MASTER optical counterpart detection
  77. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  78. Swift GRB 251201B: Global MASTER-Net observations report
  79. GRB 251201B: Enhanced Swift-XRT position
  80. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  81. GRB 251130B: AstroSat CZTI detection
  82. GRB 251201B: Swift detection of a burst with an optical counterpart
  83. GRB 251201B: Fermi GBM Final Real-time Localization
  84. EP251130a: Mondy optical observations
  85. EP251130a: SAO RAS optical observations
  86. EP251130a: KAIT optical observations
  87. GRB 251201A: MAXI/GSC detection
  88. Fermi GRB 251130B: Global MASTER-Net observations report
  89. GRB 251127A: SVOM/GRM observation
  90. GRB 251130B: Fermi GBM Final Localization Correction
  91. GRB 251130B: Fermi GBM Final Real-time Localization
  92. EP251129a/GRB 251129A: EP-FXT follow-up observations
  93. GRB 251130A: Fermi GBM Final Real-time Localization
  94. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  95. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  96. GRB 251128A: AstroSat CZTI detection
  97. GRB 251129A / EP251129a: SAO RAS optical observations
  98. GRB 251126A: SAO RAS optical observations
  99. GRB 251128A: GECAM-B detection
  100. GRB 251128A: SVOM/GRM observation of a long burst

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