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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

26164 results found.

  1. SVOM GRB251211.12: Global MASTER-Net observations report
  2. GRB 251211A: Fermi GBM Final Real-time Localization
  3. GRB 251209A: Fermi GBM observation
  4. GRB 251205A: 1.3m DFOT optical upper limit
  5. IceCube Alert 251210.46: Global MASTER-Net observations report
  6. EP251130a: Mondy and AbAO optical observations
  7. Fermi GBM Sub-Threshold Detection of GRB 251205A
  8. GRB 251208B: COLIBRÍ optical upper limits
  9. EP251118a / GRB 251118C: VLT/MUSE redshift confirmation
  10. GRB 251208C: GECAM-B observation of a short burst
  11. GRB 251208A: GECAM-B observation of a short burst
  12. Fermi GRB 251209A: Global MASTER-Net observations report
  13. Fermi GRB 251208C: Global MASTER-Net observations report
  14. GRB 251206A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  15. GRB 251209A: Fermi GBM Final Real-time Localization
  16. GRB 251208B: Fermi GBM Observation
  17. GRB 251208B: GROWTH-India Telescope optical upper limits
  18. GRB 251205A: J-band detection with WINTER
  19. GRB 251208D: Swift-XRT observations
  20. GRB 251208A: SVOM/GRM observation of a short burst
  21. GRB 251208C: SVOM/GRM observation of a short burst
  22. LAT GRB251208.43: Global MASTER-Net observations report
  23. GRB 251205A: Liverpool Telescope further optical follow-up observations
  24. GRB 251208D: LCO optical upper limits
  25. SVOM GRB251208D: Global MASTER-Net observations report
  26. GRB 251208B: Fermi-LAT detection
  27. GRB 251208B: Swift/BAT-GUANO arcminute localization of a burst
  28. GRB 251208D: SVOM possible detection of a faint burst
  29. GRB 251206A: SVOM detection of a burst through offline search
  30. GRB 251208C: Fermi GBM Final Real-time Localization
  31. GRB 251205A : MITSuME Akeno optical afterglow candidate detection
  32. GRB 251208B: Fermi GBM Final Real-time Localization
  33. GRB 251208A: Fermi GBM Final Real-time Localization
  34. EP-WXT trigger 01709249380: KAIT confirmation of a stellar flare
  35. GRB 251205A: Liverpool Telescope further optical follow-up observations
  36. SVOM GRB251206.86: Global MASTER-Net observations report
  37. EP-WXT trigger 01709249380: confirmation of a stellar flare by BOOTES-5
  38. The EP-WXT trigger 01709249380 is likely a flaring star
  39. GRB 251205A: GROWTH-India Telescope optical observations
  40. GRB 251205A: Swift-BAT refined analysis
  41. GRB 251205A: Swift-XRT refined Analysis
  42. GRB 251205A: Swift/UVOT Detection
  43. GRB 251205A: Liverpool Telescope optical follow-up observations
  44. GRB 251203C: Swift/UVOT Upper Limit
  45. GRB 251205A: COLIBRÍ optical observations
  46. GRB 251205A: GOTO optical afterglow detection
  47. GRB 251205A: NOT optical observations
  48. GRB 251205A: GTC/OSIRIS+ redshift z = 1.100
  49. GRB 251205A: Swift detection of a burst with an optical afterglow
  50. Swift GRB251205A: Global MASTER-Net observations report
  51. GRB 251126B: Fermi GBM Final Localization
  52. GRB 251203C: SVOM/ECLAIRs refined analysis
  53. SVOM/sb25120502: SVOM detection of a faint X-ray transient candidate
  54. GRB 251202A / EP251202a: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 40-cm and 1-m telescopes at McDonald Observatory
  55. GRB 251203C: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  56. GRB 251202A: SVOM/GRM observation
  57. GRB 251203A: GECAM-B observation of a burst
  58. GRB 251203A: SVOM/GRM observation
  59. GRB 251201B: SALT spectroscopic redshift z = 1.599
  60. GRB 251203C: J-band observations with WINTER
  61. Fermi Gamma-ray Burst Monitor trigger 786496343/251203967 is not a GRB
  62. GRB 251203C: LCO optical afterglow confirmation
  63. GRB 251203C: SVOM/VT optical counterpart
  64. GRB 251203C: EP-FXT follow-up observation
  65. GRB 251129A/EP251129a : SVOM/ECLAIRs refined analysis
  66. GRB 251129B: GECAM-B observation of a burst
  67. GRB 251203B: Swift-XRT observations
  68. GRB 251203B: confirmation of a stellar flare by BOOTES-2
  69. GRB 251203B : SVOM trigger sb25120304 is not a GRB
  70. GRB 251203C: LCO optical upper limits
  71. GRB 251203B: LCO optical upper limits
  72. GRB 251203B: SVOM/VT optical observation
  73. GRB 251202A / EP251202a: Liverpool Telescope optical follow-up observations
  74. GRB 251203C: SVOM detection of a burst
  75. SVOM GRB251203.77: Global MASTER-Net observations report
  76. SVOM GRB251203B: Global MASTER-Net observations report
  77. GRB 251203B: SVOM detection of a burst
  78. GRB 251129A / EP251129a: SVOM/VT optical color bluer
  79. GRB 251203A: Fermi GBM Final Real-time Localization
  80. GRB 251202A / EP251202a: SVOM/VT optical observation
  81. GRB 251201B: Fermi GBM Observation
  82. EP251130a: ULL-ASTRO-MASTER late detection of the optical afterglow with LCO 1-m telescope at Teide Observatory
  83. Fermi GRB 251202B: Global MASTER-Net observations report
  84. GRB 251202B: Fermi GBM Final Real-time Localization
  85. GRB251129A/EP251129a: Swift UVOT detection
  86. GRB 251202A: Fermi GBM Observation
  87. GRB 251202A: Swift/UVOT Detection
  88. GRB 251201B: Kilonova-Catcher optical afterglow detection
  89. GRB 251201B: Swift/UVOT Detection
  90. GRB 251130B: Glowbug gamma-ray detection
  91. GRB 251201B: GECAM-B observation of a long burst
  92. EP251130a: continued NOT optical observations indicate steep fading phase
  93. EP251202a / GRB 251202A: LCO r- and i-band optical detection
  94. GRB 251202A: GOTO optical afterglow detection
  95. EP251202a/GRB 251202A: refined analysis of the EP-WXT observations
  96. GRB 251201A: GECAM-B observation of a burst
  97. GRB 251126A: SVOM/VT optical observation
  98. EP251130a: SVOM/VT optical observation
  99. EP251202a / GRB 251202A: NOT spectroscopic redshift z = 2.785
  100. Fermi GRB 251202A: Global MASTER-Net observations report

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