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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"

35422 results found.

  1. GRB 240205A (short): Glowbug gamma-ray detection
  2. GRB240204A: Swift/UVOT Upper Limits
  3. GRB 240205B: AstroSat CZTI detection
  4. GRB 240205B: Swift-BAT refined analysis
  5. Konus-Wind detection of GRB 240205B (long / very soft)
  6. GRB 240207A: Fermi GBM Final Real-time Localization
  7. Konus-Wind detection of GRB 240125A
  8. GRB 240205B: VLT/X-shooter redshift
  9. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  10. GRB 240205B: BOOTES-6 optical afterglow follow-up
  11. GRB 240205B: ATCA detection of radio counterpart
  12. GRB 240205B: REM detection of the optical/NIR afterglow
  13. GRB 240205B: Fermi GBM Observation
  14. GRB 240204A: AstroSat CZTI detection
  15. GRB 240204A: Mondy optical afterglow observations
  16. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  17. GRB 240205B: GECAM detection of a long burst
  18. GRB 240204A: Swift-BAT refined analysis
  19. GRB 240205B: Skynet Optical Afterglow Observations
  20. GRB 240205B: BOOTES-7 optical afterglow follow-up
  21. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  22. GRB 240205B: Swift detection of a burst
  23. GRB 240205B: Fermi GBM Final Real-time Localization
  24. GRB 240204A: Fermi GBM Observation
  25. GRB 240205A: Fermi GBM Final Real-time Localization
  26. GRB 240204a: Liverpool Telescope optical afterglow detection
  27. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  28. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  29. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  30. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  31. GRB 240204A: Montarrenti Observatory optical observations
  32. GRB 240204A: Enhanced Swift-XRT position
  33. GRB 240204A: Mondy optical afterglow candidate
  34. Fermi Gamma-ray Burst Monitor trigger 728706420/240204102 is not a GRB
  35. Fermi GRB 240204A: Global MASTER-Net observations report
  36. GRB 240204A: Swift detection of a burst
  37. GRB 240204A: Fermi GBM Final Real-time Localization
  38. GRB 230812B: Update on Bad Time Intervals for Fermi GBM data
  39. Konus-Wind detection of GRB 240124B
  40. Konus-Wind detection of GRB 240123C
  41. IPN triangulation of GRB 240124B
  42. GRB 240201A: AstroSat CZTI detection
  43. GRB 240129A: Fermi GBM Observation
  44. IPN triangulation of GRB 240125B (short)
  45. GRB 240129A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  46. IPN triangulation of GRB 240125A (short)
  47. GRB 240128A: Glowbug gamma-ray detection
  48. GRB 240128A: Swift-XRT observations
  49. GRB 240128A: GRBAlpha detection
  50. GRB 240128A: Tiled Swift observations
  51. GRB 240128A: CALET Gamma-Ray Burst Monitor detection
  52. GRB 240128A: MAXI/GSC detection
  53. GRB 240125A: GRBAlpha detection
  54. Fermi GRB 240127A: Global MASTER-Net observations report
  55. GRB 240123C: GRBAlpha detection
  56. GRB 240122A: ATCA detection of radio counterpart
  57. GRB 240127A: Fermi GBM Final Real-time Localization
  58. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 240125A: CALET Gamma-Ray Burst Monitor detection
  60. GRB 240125A: AstroSat CZTI detection of a short burst
  61. GRB 240124B: AstroSat CZTI detection
  62. GRB 240123C: AstroSat CZTI detection
  63. GRB 240125B: Fermi GBM Final Localization
  64. GRB 240123B: Fermi GBM Observation
  65. GRB 240123A: Glowbug gamma-ray detection
  66. GRB 240125A (short): Glowbug gamma-ray detection
  67. GRB 240123B: Swift/BAT-GUANO detection of a long burst
  68. GRB 240123A: GRBAlpha detection
  69. IPN triangulation of GRB 240123C (short)
  70. GRB 240123A: further SAO RAS optical observations
  71. GRB 240122B: CALET Gamma-Ray Burst Monitor detection
  72. GRB 240123A: Swift-BAT refined analysis
  73. GRB 240123A: Mondy continued optical observations and the PL decay index
  74. GRB 240123A: SAO RAS optical observations
  75. GRB 240123A : MITSuME Akeno optical afterglow candidate detection
  76. Fermi/GBM trigger 727752941: BALROG analysis retraction
  77. GRB 240123A: Enhanced Swift-XRT position
  78. GRB 240124A?: BALROG localization (Fermi Trigger 727752941 / GRB 240124066)
  79. Fermi GRB 240123B: Global MASTER-Net observations report
  80. GRB 240122A: Swift/UVOT Upper Limits
  81. GRB 240123A: Swift-XRT refined Analysis
  82. GRB 240122A: BOOTES-2/TELMA optical upper limit and 1.5m OSN detection
  83. Fermi GBM Sub-Threshold Detection of GRB 240123A
  84. GRB 240123A: Mondy continued optical observations + correction of the GRB name in GCN 35605
  85. GRB 240123B: Fermi GBM Final Real-time Localization
  86. GRB 240118A: Swift/UVOT Upper Limits
  87. GRB 240122B: Glowbug gamma-ray detection
  88. GRB 240123A: Mondy optical afterglow observations
  89. Konus-Wind detection of GRB 240112A
  90. GRB 240123A: Swift detection of a burst with a possible optical counterpart
  91. GRB 240122A: Swift-XRT afterglow detection
  92. GRB 240122A: VLT/X-shooter redshift confirmation
  93. GRB 240122A: Redshift from OSIRIS+/GTC
  94. GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
  95. GRB 240122A: GOTO optical counterpart candidate
  96. GRB 240122A: Tiled Swift observations
  97. Konus-Wind detection of GRB 240119A (short/hard)
  98. GRB 240122A: MAXI/GSC detection
  99. IPN triangulation of GRB 240119A (short)
  100. GRB 240119A: GECAM detection of a short burst

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