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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"

12409 results found.

  1. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  2. GRB 251202A: SVOM/GRM observation
  3. GRB 251203A: GECAM-B observation of a burst
  4. GRB 251203A: SVOM/GRM observation
  5. GRB 251201B: SALT spectroscopic redshift z = 1.599
  6. GRB 251203A: AstroSat CZTI detection
  7. Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
  8. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  9. GRB 251201B: Insight-HXMT/HE detection
  10. EP251202a / GRB 251202A: Insight-HXMT/HE detection
  11. GRB 251203A: Fermi GBM Final Real-time Localization
  12. EP251202a / GRB251202A: AstroSat CZTI detection
  13. GRB 251202A / EP251202a: SVOM/VT optical observation
  14. GRB 251201B: Fermi GBM Observation
  15. EP251202a/GRB 251202A: KAIT optical observations
  16. Fermi GRB 251202B: Global MASTER-Net observations report
  17. GRB 251202B: Fermi GBM Final Real-time Localization
  18. GRB 251202A: Fermi GBM Observation
  19. GRB 251201B: Kilonova-Catcher optical afterglow detection
  20. GRB 251130B: Glowbug gamma-ray detection
  21. GRB 251201B: GECAM-B observation of a long burst
  22. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  23. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  24. GRB 251202A: GOTO optical afterglow detection
  25. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  26. Fermi GRB 251202A: Global MASTER-Net observations report
  27. EP251202a/GRB 251202A: Einstein Probe detection of an X-ray transient
  28. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 251202A: Fermi GBM Final Real-time Localization
  30. GRB 251201B: SVOM/VT optical fading
  31. Swift GRB 251201B : MASTER optical counterpart detection
  32. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  33. GRB 251130B: AstroSat CZTI detection
  34. GRB 251201B: Fermi GBM Final Real-time Localization
  35. Fermi GRB 251130B: Global MASTER-Net observations report
  36. GRB 251127A: SVOM/GRM observation
  37. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  38. GRB 251130B: Fermi GBM Final Localization Correction
  39. GRB 251130B: Fermi GBM Final Real-time Localization
  40. GRB 251130A: Fermi GBM Final Real-time Localization
  41. GRB 251128A: AstroSat CZTI detection
  42. GRB 251128A: GECAM-B detection
  43. GRB 251128A: SVOM/GRM observation of a long burst
  44. GRB 251128A: Insight-HXMT/HE detection
  45. GRB 251128A: Fermi GBM Observation
  46. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  47. Fermi GRB 251128A: Global MASTER-Net observations report
  48. GRB 251127A: Glowbug gamma-ray detection
  49. GRB 251128A: Fermi GBM Final Real-time Localization
  50. GRB 251125B: GECAM-B detection
  51. Fermi GRB 251127A: Global MASTER-Net observations report
  52. GRB 251127A: Fermi GBM Final Real-time Localization
  53. GRB 251121A: Fermi GBM Observation
  54. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  55. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  56. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  57. Fermi GRB 251125B: Global MASTER-Net observations report
  58. GRB 251125B: Fermi GBM Final Real-time Localization
  59. Fermi GRB 251125A: Global MASTER-Net observations report
  60. GRB 251125A: Fermi GBM Final Real-time Localization
  61. GRB 251124A: Fermi GBM Localization by automated pipeline
  62. GRB 251122B: Fermi GBM Final Localization
  63. Fermi GRB 251124a: Global MASTER-Net observations report
  64. GRB 251124a: Fermi GBM Final Localization
  65. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  66. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  67. GRB 251115A: Fermi GBM Observation
  68. GRB 251121A: Fermi GBM Final Real-time Localization
  69. Fermi Gamma-ray Burst Monitor trigger 785388351 / 251121143 is not a GRB
  70. Fermi trigger No 785388351: Global MASTER-Net observations report
  71. GRB 251118A: Swift/UVOT Detection
  72. GRB 251118A: Glowbug gamma-ray detection
  73. GRB 251118A: Fermi GBM Observation
  74. GRB 251118A: Swift-XRT afterglow detection
  75. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  76. GRB 251118A: GECAM-B detection
  77. GRB 251118A: NuSTAR detection of bright prompt emission
  78. GRB 251117A: Swift-XRT observations
  79. GRB 251117A: Insight-HXMT/HE detection
  80. GRB 251118A: Fermi-LAT detection
  81. GRB 251118A: Swift ToO observations
  82. Fermi GRB 251118B: Global MASTER-Net observations report
  83. GRB 251118B: Fermi GBM Final Real-time Localization
  84. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  85. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  86. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  87. GRB 251118A: Fermi GBM Final Real-time Localization
  88. GRB 251117A: AstroSat CZTI detection
  89. GRB 251114B: Insight-HXMT/HE detection
  90. GRB 251114B: GECAM-B detection of a short burst
  91. GRB 251117A: Fermi GBM observation
  92. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  93. GRB 251115A: Swift-XRT observations
  94. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  95. GRB 251117A: SVOM/GRM observation of a short burst
  96. GRB 251117A: Tiled Swift observations
  97. GRB 251117A: Fermi-LAT detection
  98. GRB 251117A: Fermi GBM Final Localization Correction
  99. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  100. GRB 251116A: Fermi GBM Final Real-time Localization

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