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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"

36143 results found.

  1. GRB 240215A: Tiled Swift observations
  2. GRB 240215A: Swift/BAT-GUANO localization of a burst
  3. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  4. GRB 240209A: Fermi GBM observation
  5. GRB 240213A: Glowbug gamma-ray detection
  6. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  7. GRB 240209A: Wendelstein Optical Observations
  8. GRB 240128A: Further Swift-XRT observations
  9. GRB 240214A: Tiled Swift observations
  10. GRB 240214A/1H 0451-560: MAXI/GSC detection
  11. GRB 240213A: BALROG localization (Fermi Trigger / GRB 240213841)
  12. Fermi GRB 240213A: Global MASTER-Net observations report
  13. GRB 240213A: Fermi GBM Final Real-time Localization
  14. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  15. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  16. GRB 240209A: GOTO optical counterpart candidate
  17. Konus-Wind detection of GRB 240204A
  18. Konus-Wind detection of GRB 240205A (short)
  19. GRB 240209A: Fermi GBM Final Localization
  20. IPN triangulation of GRB 240205A (short)
  21. GRB 240205B: PRIME near infrared detection
  22. GRB 240205A (short): Glowbug gamma-ray detection
  23. GRB240204A: Swift/UVOT Upper Limits
  24. GRB 240205B: AstroSat CZTI detection
  25. GRB 240205B: Swift-BAT refined analysis
  26. Konus-Wind detection of GRB 240205B (long / very soft)
  27. GRB 240207A: Fermi GBM Final Real-time Localization
  28. Konus-Wind detection of GRB 240125A
  29. GRB 240205B: VLT/X-shooter redshift
  30. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  31. GRB 240205B: BOOTES-6 optical afterglow follow-up
  32. GRB 240205B: ATCA detection of radio counterpart
  33. GRB 240205B: REM detection of the optical/NIR afterglow
  34. GRB 240205B: Fermi GBM Observation
  35. GRB 240204A: AstroSat CZTI detection
  36. GRB 240204A: Mondy optical afterglow observations
  37. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  38. GRB 240205B: GECAM detection of a long burst
  39. GRB 240204A: Swift-BAT refined analysis
  40. GRB 240205B: Skynet Optical Afterglow Observations
  41. GRB 240205B: BOOTES-7 optical afterglow follow-up
  42. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  43. GRB 240205B: Swift detection of a burst
  44. GRB 240205B: Fermi GBM Final Real-time Localization
  45. GRB 240204A: Fermi GBM Observation
  46. GRB 240205A: Fermi GBM Final Real-time Localization
  47. GRB 240204a: Liverpool Telescope optical afterglow detection
  48. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  49. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  50. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  51. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  52. GRB 240204A: Montarrenti Observatory optical observations
  53. GRB 240204A: Enhanced Swift-XRT position
  54. GRB 240204A: Mondy optical afterglow candidate
  55. Fermi Gamma-ray Burst Monitor trigger 728706420/240204102 is not a GRB
  56. Fermi GRB 240204A: Global MASTER-Net observations report
  57. GRB 240204A: Swift detection of a burst
  58. GRB 240204A: Fermi GBM Final Real-time Localization
  59. GRB 230812B: Update on Bad Time Intervals for Fermi GBM data
  60. Konus-Wind detection of GRB 240124B
  61. Konus-Wind detection of GRB 240123C
  62. IPN triangulation of GRB 240124B
  63. GRB 240201A: AstroSat CZTI detection
  64. GRB 240129A: Fermi GBM Observation
  65. IPN triangulation of GRB 240125B (short)
  66. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  67. IPN triangulation of GRB 240125A (short)
  68. GRB 240128A: Glowbug gamma-ray detection
  69. GRB 240128A: Swift-XRT observations
  70. GRB 240128A: GRBAlpha detection
  71. GRB 240128A: Tiled Swift observations
  72. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 240128A: MAXI/GSC detection
  74. GRB 240125A: GRBAlpha detection
  75. Fermi GRB 240127A: Global MASTER-Net observations report
  76. GRB 240123C: GRBAlpha detection
  77. GRB 240122A: ATCA detection of radio counterpart
  78. GRB 240127A: Fermi GBM Final Real-time Localization
  79. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB 240125A: CALET Gamma-Ray Burst Monitor detection
  81. GRB 240125A: AstroSat CZTI detection of a short burst
  82. GRB 240124B: AstroSat CZTI detection
  83. GRB 240123C: AstroSat CZTI detection
  84. GRB 240125B: Fermi GBM Final Localization
  85. GRB 240123B: Fermi GBM Observation
  86. GRB 240123A: Glowbug gamma-ray detection
  87. GRB 240125A (short): Glowbug gamma-ray detection
  88. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  89. GRB 240123A: GRBAlpha detection
  90. IPN triangulation of GRB 240123C (short)
  91. GRB 240123A: further SAO RAS optical observations
  92. GRB 240122B: CALET Gamma-Ray Burst Monitor detection
  93. GRB 240123A: Swift-BAT refined analysis
  94. GRB 240123A: Mondy continued optical observations and the PL decay index
  95. GRB 240123A: SAO RAS optical observations
  96. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  97. Fermi/GBM trigger 727752941: BALROG analysis retraction
  98. GRB 240123A: Enhanced Swift-XRT position
  99. GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
  100. Fermi GRB 240123B: Global MASTER-Net observations report

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