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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"

38676 results found.

  1. GRB 251203A: SVOM/GRM observation
  2. GRB 251201B: SALT spectroscopic redshift z = 1.599
  3. GRB 251129B: Glowbug gamma-ray detection of a short burst
  4. GRB 251203A: AstroSat CZTI detection
  5. Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
  6. GRB 251203C: LCO optical afterglow confirmation
  7. GRB 251203C: SVOM/VT optical counterpart
  8. GRB 251203C: EP-FXT follow-up observation
  9. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  10. GRB 251129B: GECAM-B observation of a burst
  11. GRB 251203B: Swift-XRT observations
  12. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  13. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  14. GRB 251203C: LCO optical upper limits
  15. GRB 251203B: LCO optical upper limits
  16. GRB 251203B: SVOM/VT optical observation
  17. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  18. GRB 251203C: SVOM detection of a burst
  19. SVOM GRB251203.77: Global MASTER-Net observations report
  20. SVOM GRB251203B: Global MASTER-Net observations report
  21. GRB 251203B: SVOM detection of a burst
  22. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  23. GRB 251201B: Insight-HXMT/HE detection
  24. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  25. EP251130a: MAO/AZT-22 optical observations
  26. GRB 251203A: Fermi GBM Final Real-time Localization
  27. EP251202a / GRB251202A: AstroSat CZTI detection
  28. GRB 251202A / EP251202a: SVOM/VT optical observation
  29. GRB 251201B: Fermi GBM Observation
  30. EP251202a/GRB 251202A: KAIT optical observations
  31. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  32. GRB 251202B: Fermi GBM Final Real-time Localization
  33. IPN triangulation of GRB 251129B (short/hard)
  34. GRB251129A/EP251129a: Swift UVOT detection
  35. GRB 251129B: AstroSat CZTI detection
  36. GRB 251202A: Fermi GBM Observation
  37. GRB 251202A: Swift/UVOT Detection
  38. GRB 251201B: Kilonova-Catcher optical afterglow detection
  39. GRB 251201B: Swift/UVOT Detection
  40. GRB 251130B: Glowbug gamma-ray detection
  41. GRB 251201B: GECAM-B observation of a long burst
  42. EP251130a: continued NOT optical observations indicate steep fading phase
  43. GRB 251122A/EP251122a: CrAO ZTSh optical observations
  44. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  45. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  46. GRB 251202A: GOTO optical afterglow detection
  47. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  48. GRB 251201A: GECAM-B observation of a burst
  49. GRB 251126A: SAO RAS optical marginal detection
  50. GRB 251202A: Swift-XRT afterglow detection
  51. EP251129a/GRB 251129A: NOWT Detection
  52. GRB 251126A: SVOM/VT optical observation
  53. EP251130a: SVOM/VT optical observation
  54. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  55. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  56. GRB 251201B: Swift-XRT refined Analysis
  57. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  58. GRB 251202A: Fermi GBM Final Real-time Localization
  59. GRB 251201A: SVOM/GRM observation of a burst
  60. GRB 251201B: SVOM/VT optical fading
  61. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  62. GRB 251201B: Enhanced Swift-XRT position
  63. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  64. GRB 251130B: AstroSat CZTI detection
  65. GRB 251201B: Swift detection of a burst with an optical counterpart
  66. GRB 251201B: Fermi GBM Final Real-time Localization
  67. EP251130a: Mondy optical observations
  68. EP251130a: Optical detections with Kinder observations
  69. SVOM GRB251201.19: Global MASTER-Net observations report
  70. EP251130a: SAO RAS optical observations
  71. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  72. EP251130a: KAIT optical observations
  73. EP251130A: Optical observation from 1.3m DFOT
  74. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  75. EP251130a: JinShan optical observations
  76. GRB 251201A: MAXI/GSC detection
  77. GRB 251127A: SVOM/GRM observation
  78. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  79. EP251130a: Swift-XRT counterpart detection
  80. GRB 251130B: Fermi GBM Final Localization Correction
  81. GRB 251130B: Fermi GBM Final Real-time Localization
  82. EP251130a: COLIBRÍ optical counterpart candidate
  83. EP251130a: Einstein Probe detection of an X-ray transient
  84. EP251129a/GRB 251129A: EP-FXT follow-up observations
  85. GRB 251130A: Fermi GBM Final Real-time Localization
  86. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  87. GRB 251129A / EP251129a: OSN and CAHA optical follow-up
  88. GRB 251128A: AstroSat CZTI detection
  89. GRB 251129A / EP251129a: SAO RAS optical observations
  90. GRB 251126A: SAO RAS optical observations
  91. GRB 251128A: GECAM-B detection
  92. GRB 251128A: SVOM/GRM observation of a long burst
  93. GRB 251128A: Insight-HXMT/HE detection
  94. SVOM GRB 251129A : MASTER optical counterpart detection
  95. GRB 251129A: Swift-XRT afterglow detection
  96. The EP-WXT trigger 01709248941 is triggered by the known source Perseus Cluster
  97. Swift trigger 1418333 is not an astrophysical source
  98. GRB 251129A: Swift ToO observations
  99. GRB 251129A / EP251129a: SVOM/VT optical fading
  100. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy

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