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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"

38673 results found.

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

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