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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"

32101 results found.

  1. GRB 240222A: GRBAlpha detection
  2. VLA X-band observation of EPW20240219aa
  3. Transient EPW20240219aa: Mondy optical observations
  4. Transient EPW20240219aa: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
  5. Swift BAT Sub-Threshold Detection of EPW20240219aa
  6. GRB 240222A: GECAM detection of a burst
  7. GRB 240222A: Swift-BAT refined analysis
  8. GRB 240222A: Swift-XRT refined Analysis
  9. GRB 240222A: Fermi GBM Observation
  10. GRB 240222A: Swift/UVOT Upper Limits
  11. Fermi GBM Sub-Threshold Detection of EPW20240219aa as a likely GRB
  12. Swift GRB 240222A: Global MASTER-Net observations report
  13. Fermi GRB 240222A: Global MASTER-Net observations report
  14. EPW20240219aa is Likely a GRB Event
  15. GRB 240222A: REM optical and NIR early-time observations
  16. GRB 240222A: Swift detection of a burst
  17. GRB 240222A: Fermi GBM Final Real-time Localization
  18. GRB 240218A: MeerLICHT upper limits
  19. GRB 240216A: Glowbug gamma-ray detection
  20. GRB 240215B: Fermi GBM Observation
  21. GRB 240218A: LBT H-band detection
  22. GRB 240218A: Swift-BAT refined analysis
  23. Fermi GRB 240220A: Global MASTER-Net observations report
  24. GRB 240220A: Fermi GBM Final Real-time Localization
  25. Konus-Wind detection of GRB 240218A
  26. GRB 240218A: Swift-XRT refined Analysis
  27. GRB 240218A: VLT/X-shooter redshift of z = 6.782
  28. GRB 240218A: Fermi GBM Detection
  29. GRB 240215A: Fermi GBM Observation
  30. GRB 240216A: GRBAlpha detection
  31. GRB 240215B: GRBAlpha detection
  32. IPN triangulation of GRB 240209A
  33. GRB 240218A: VLT/FORS2 z-band detection
  34. GRB 240218A: Enhanced Swift-XRT position
  35. GRB 240218A: REM detection of a NIR afterglow candidate
  36. GRB 240213A: GRBAlpha detection
  37. GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
  38. GRB240218A: VLT/X-shooter upper limits
  39. GRB 240218A: Swift detection of a burst
  40. GRB 240215C: Fermi GBM Final Real-time Localization
  41. GRB 240215B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  42. Fermi GRB 240216A: Global MASTER-Net observations report
  43. GRB 240216A: Fermi GBM Final Real-time Localization
  44. GRB 240215A: Tiled Swift observations
  45. GRB 240215A: Swift/BAT-GUANO localization of a burst
  46. GRB 240209A: Classification of AT2024cew/GOTO24pw as Type Ia-pec supernova
  47. GRB 240209A: Fermi GBM observation
  48. GRB 240213A: Glowbug gamma-ray detection
  49. GRB240209A: OHP/T193 detection of the GOTO afterglow candidate AT2024cew / GOTO24pw
  50. GRB 240209A: Wendelstein Optical Observations
  51. GRB 240128A: Further Swift-XRT observations
  52. GRB 240214A: Tiled Swift observations
  53. GRB 240214A/1H 0451-560: MAXI/GSC detection
  54. GRB 240213A: BALROG localization (Fermi Trigger / GRB 240213841)
  55. Fermi GRB 240213A: Global MASTER-Net observations report
  56. GRB 240213A: Fermi GBM Final Real-time Localization
  57. GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
  58. GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
  59. GRB 240209A: GOTO optical counterpart candidate
  60. Konus-Wind detection of GRB 240204A
  61. Konus-Wind detection of GRB 240205A (short)
  62. GRB 240209A: Fermi GBM Final Localization
  63. IPN triangulation of GRB 240205A (short)
  64. GRB 240205B: PRIME near infrared detection
  65. GRB 240205A (short): Glowbug gamma-ray detection
  66. GRB240204A: Swift/UVOT Upper Limits
  67. GRB 240205B: AstroSat CZTI detection
  68. GRB 240205B: Swift-BAT refined analysis
  69. Konus-Wind detection of GRB 240205B (long / very soft)
  70. GRB 240207A: Fermi GBM Final Real-time Localization
  71. Konus-Wind detection of GRB 240125A
  72. GRB 240205B: VLT/X-shooter redshift
  73. GRB 240205B: CALET Gamma-Ray Burst Monitor detection
  74. GRB 240205B: BOOTES-6 optical afterglow follow-up
  75. GRB 240205B: ATCA detection of radio counterpart
  76. GRB 240205B: REM detection of the optical/NIR afterglow
  77. GRB 240205B: Fermi GBM Observation
  78. GRB 240204A: AstroSat CZTI detection
  79. GRB 240204A: Mondy optical afterglow observations
  80. GRB 240204A : OHP/T193/T120 optical afterglow fading detection
  81. GRB 240205B: GECAM detection of a long burst
  82. GRB 240204A: Swift-BAT refined analysis
  83. GRB 240205B: Skynet Optical Afterglow Observations
  84. GRB 240205B: BOOTES-7 optical afterglow follow-up
  85. GRB 240205B: MASTER OT J232550.14-550704.6 counterpart detection
  86. GRB 240205B: Swift detection of a burst
  87. GRB 240205B: Fermi GBM Final Real-time Localization
  88. GRB 240204A: Fermi GBM Observation
  89. GRB 240205A: Fermi GBM Final Real-time Localization
  90. GRB 240204a: Liverpool Telescope optical afterglow detection
  91. GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
  92. Fermi Gamma-ray Burst Monitor trigger 728740048/240204491 is not a GRB
  93. GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
  94. GRB 240204A: Montarrenti Observatory optical observations
  95. GRB 240204A: Enhanced Swift-XRT position
  96. GRB 240204A: Mondy optical afterglow candidate
  97. Fermi Gamma-ray Burst Monitor trigger 728706420/240204102 is not a GRB
  98. Fermi GRB 240204A: Global MASTER-Net observations report
  99. GRB 240204A: Swift detection of a burst
  100. GRB 240204A: Fermi GBM Final Real-time Localization

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