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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"

36318 results found.

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

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