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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"

37770 results found.

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

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