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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"

37709 results found.

  1. GRB 251103A: NOT optical afterglow candidate (duplicate submission)
  2. GRB 251103A: Fermi GBM Final Localization
  3. GRB 251103A: NOT optical afterglow candidate
  4. GRB 251103A: SVOM detection of a bright burst
  5. GRB 251102B: Fermi GBM Final Real-time Localization
  6. Fermi GRB 251102A: Global MASTER-Net observations report
  7. GRB 251102A: Fermi GBM Final Real-time Localization
  8. GRB 251031A: Fermi GBM Observation
  9. GRB 251031A: Swift/BAT-GUANO localization skymap of a burst
  10. Konus-Wind detection of GRB 251028A
  11. GRB 251031A: BALROG localization (Fermi Trigger 783588065 / GRB 251031306)
  12. GRB 251031A: Fermi GBM Final Real-time Localization
  13. GRB 251025C: SVOM/GRM observation
  14. GRB 251028A: GECAM-B detection
  15. GRB 251028A: SVOM/GRM observation
  16. GRB 251028A: Fermi GBM Observation
  17. GRB 251026B: SOAR Classification of GOTO25jgl/SN2025absf as a Type Ia supernova
  18. GRB 251022A: Swift-XRT confirmation of fading
  19. GRB 251026B: LBT near-infrared observations
  20. GRB 250926B: VZLUSAT-2 detection
  21. GRB 250926A: VZLUSAT-2 detection
  22. GRB 250925A: VZLUSAT-2 detection
  23. GRB 251026B: Fermi GBM Observation
  24. GRB 251026A/EP251026a: SVOM/VT optical counterpart
  25. GRB 251026A/EP251026a: EP-FXT follow-up observation
  26. GRB 251028B: Fermi/GBM observation
  27. GRB 251028B: Swift/BAT-GUANO localization skymap of a burst
  28. GRB 251028B: Glowbug gamma-ray detection
  29. GRB 251028A: Glowbug gamma-ray detection
  30. GRB 251028B: CALET Gamma-Ray Burst Monitor detection
  31. Fermi GRB 251028B: Global MASTER-Net observations report
  32. GRB 251025B: GROWTH-India Telescope continued multiband optical observations and rebrightening
  33. GRB 251028B: Fermi GBM Final Localization Correction
  34. GRB251026B: PRIME H-band upper limit
  35. GRB251025B: 3.6m DOT Optical Observations
  36. GRB 251028A: BALROG localization (Fermi Trigger 783314796 / GRB 251028143)
  37. GRB 251028A: MAXI/GSC detection
  38. GRB 251028A: Fermi GBM Final Real-time Localization
  39. SVOM trigger sb25102702/GRB 251027A is not a GRB
  40. GRB 251025B: Swift-XRT confirmation of fading
  41. GRB 251013C : 3.4-m telescope of Iranian National Observatory (INO340) optical observations
  42. GRB 251026B: Swift-XRT observations of GOTO25jgl/AT2025absf
  43. GRB 251025C: Glowbug gamma-ray detection
  44. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  45. GRB 251023B: Swift-UVOT Upper Limits
  46. Konus-Wind detection of GRB 251022A
  47. GRB 251027A: Swift-XRT observations
  48. GRB 251022A: SVOM/GRM observation
  49. GRB 251026B: Swift ToO observations
  50. GRB 251026A/EP251026a: Einstein Probe detection of a fast X-ray transient
  51. GRB 251027A: LCO optical upper limit
  52. GRB 251027A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  53. GRB 251017A: Mondy AZT-33IK and Koshka Zeiss-1000 optical observations
  54. GRB 251023B / EP251023b: Mondy optical upper limit
  55. GRB 251017A: INASAN-Kislovodsk optical observations
  56. GRB 251026A: Mondy optical upper limit
  57. GRB 251025B: Mondy optical observations
  58. GRB 251025B: Kilonova-Catcher optical afterglow detection
  59. Konus-Wind detection of GRB 251016A (short/hard)
  60. GRB 251025B: VLT/MUSE spectroscopic redshift z = 2.003
  61. GRB 251027A: SVOM detection of a faint burst
  62. GRB 251026B: Tentative GOTO optical counterpart candidate
  63. GRB 251025C: AstroSat CZTI detection
  64. EP251023a: Mondy optical observations
  65. GRB 251025C: CALET Gamma-Ray Burst Monitor detection
  66. GRB 251025B: MAO/AZT-22 optical observations
  67. Fermi GRB 251026B: Global MASTER-Net observations report
  68. Fermi GRB 251025C: Global MASTER-Net observations report
  69. GRB 251026A: Swift-XRT observations
  70. GRB 251025B: OHP/T193 optical detection
  71. GRB 251025B: J-band detection with WINTER
  72. GRB 251026A: SVOM/C-GFT upper limit
  73. GRB 251026A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. GRB 251026B: Fermi GBM Final Localization
  75. GRB 251026A: SVOM detection of a long burst
  76. GRB 251025B: SVOM/VT optical bump
  77. GRB 251025B: SVOM/COLIBRÍ (FM-GFT) strong rebrightening of the optical counterpart
  78. GRB 251023A: SVOM/GRM observation
  79. GRB 251025B: ULL-ASTRO-MASTER optical counterpart detection with IAC80 telescope at Teide Observatory
  80. GRB 251025C: Fermi GBM Final Real-time Localization
  81. Konus-Wind detection of GRB 251016B
  82. GRB 251025B: GROWTH-India Telescope optical observations
  83. GRB 251024A: Swift/UVOT Upper Limits
  84. GRB 251025B: Swift-XRT afterglow detection
  85. GRB 251024A: Swift-BAT refined analysis
  86. GRB 251024A: Swift-XRT refined Analysis
  87. GRB 251025A (sb25102501): stellar flare confirmed
  88. GRB 251025B: SVOM/VT optical observations with VHF data
  89. GRB 251025B: MASTER OT detection
  90. GRB 251025B: SVOM/C-GFT optical counterpart detection
  91. GRB 251025B: SVOM detection of a burst
  92. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  93. GRB 251025A (sb25102501): Likely a stellar flare by SVOM/VT
  94. GRB 251025A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  95. GRB 251025A: SVOM/VT VHF optical upper limit
  96. GRB 251025A: SVOM detection of a faint burst
  97. GRB 251003A: VLA Detection
  98. GRB 251024A: Enhanced Swift-XRT position
  99. GRB 251023C: Glowbug gamma-ray detection
  100. GRB 251024A: LCOGT Optical Afterglow Detection

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