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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"

19603 results found.

  1. Swift GRB230826.81: Global MASTER-Net observations report
  2. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  3. GRB 230824A: AKO Photometric Follow-up Observations
  4. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  5. Swift GRB230825.85: Global MASTER-Net observations report
  6. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  7. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  8. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  9. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  10. Swift GRB230825.75: Global MASTER-Net observations report
  11. Swift Trigger 1187199 is not an astrophysical event
  12. Fermi Gamma-ray Burst Monitor trigger 714618399/230825046 is not a GRB
  13. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  14. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  15. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  16. GRB 230824A: AKO Optical Afterglow Candidate
  17. Trigger 1186982: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  18. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  19. GRB 230824A: Swift detection of a burst
  20. Swift GRB230824.58: Global MASTER-Net observations report
  21. Swift GRB230824.10: Global MASTER-Net observations report
  22. Swift Trigger 1186908 is not a GRB
  23. GRB 230822A: Fermi GBM Observation
  24. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  25. GRB 230822A: Swift/BAT-GUANO detection of a burst
  26. GRID detection of GRB 230818A
  27. GRB 230815A: ATCA detection of radio counterpart
  28. Swift GRB230821.64: Global MASTER-Net observations report
  29. GRB 230818A: Swift-BAT refined analysis
  30. Swift Trigger 1186391 is not a GRB
  31. Swift Trigger 1186390 is not a GRB
  32. Konus-Wind detection of GRB 230818A
  33. Swift Trigger 1186386 is not a GRB
  34. Swift triggers 1186294-1186304 are not astrophysical transients
  35. Swift GRB230820.81: Global MASTER-Net observations report
  36. Swift GRB230820.80: Global MASTER-Net observations report
  37. Swift GRB230820.82: Global MASTER-Net observations report
  38. Swift Triggers 1186280 and 1186291 are not GRBs
  39. GRB 230818A: Fermi GBM Observation
  40. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  41. GRB 230818A: AKO Upper Limit
  42. GRB 230818A: AstroSat CZTI detection
  43. GRB 230818A: Leavitt Observatory upper limit
  44. GRB 230818A: Swift-XRT refined Analysis
  45. GRB 230818A: Bassano Bresciano Observatory optical observations
  46. GRB 230818A: KGO RC-25 optical observations
  47. GRB 230818A: Swift/UVOT Detection
  48. GRB 230818A: NOT photometry and spectroscopy
  49. GRB 230818A: Enhanced Swift-XRT position
  50. GRB 230818A: Swift detection of a burst
  51. Swift GRB230818.98: Global MASTER-Net observations report
  52. Swift GRB230818.98: Global MASTER-Net OT detection
  53. GRB 230816A: Swift-BAT refined analysis
  54. GRB 230816A: SVOM/C-GFT optical detection
  55. GRB 230816A: Swift-XRT refined Analysis
  56. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  57. GRB 230816A: Enhanced Swift-XRT position
  58. GRB230816A: Possible host and GIT detection of optical counterpart
  59. Swift GRB230816.80: Global MASTER-Net observations report
  60. IPN triangulation of GRB 230815B
  61. GRB 230816A: Nanshan/HMT optical afterglow detection
  62. GRB 230815A: SOAR/Goodman follow-up imaging
  63. Swift GRB230816.67: Global MASTER-Net observations report
  64. GRB 230816A: Swift detection of a burst
  65. GRB 230815A: Swift-BAT refined analysis
  66. GRB230815A: Swift/UVOT upper limits
  67. GRB 230812B: GAD Observatory optical observations (upper limit)
  68. GRB 230815A: Swift-XRT refined Analysis
  69. GRB 230812B: iTelescope optical upper limit
  70. GRB230815A: BOOTES-6/DPRT optical upper limit
  71. GRB 230815A: Fermi GBM detection
  72. Swift GRB 230815A: Global MASTER-Net observations report
  73. GRB 230815A: Enhanced Swift-XRT position
  74. GRB 230815A: Swift detection of a burst
  75. GRB 230812B: Upper limits from a neutrino search with IceCube
  76. GRB 230812B: GIT optical follow-up
  77. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  78. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  79. GRB 230812B: OASDG optical observations
  80. GRB 230812B: Detected Optical Afterglow Candidate
  81. GRB230812B: AGILE/MCAL detection
  82. GRB 230812B: Swift-XRT afterglow detection
  83. GRB 230812: Swift/UVOT Detection
  84. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  85. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  86. Fermi GRB 230812B: MASTER optical counterpart
  87. GRB 230812B: KAIT Optical Afterglow Candidate
  88. GRB 230812B: Improved Swift/XRT localization
  89. GRB 230812B: Preliminary Swift/XRT localization
  90. GRB 230812B: Tiled Swift observations
  91. GRB 230808A: Fermi GBM Detection
  92. GRB 230805B: Swift-BAT refined analysis
  93. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  94. GRB 230805B: AstroSat CZTI detection
  95. GRB 230808A: Swift/BAT-GUANO detection of a burst
  96. GRB 230805B : MITSuME Akeno optical upper limits
  97. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  98. GRB 230805B: Fermi GBM observation
  99. GRB 230805B: Enhanced Swift-XRT position
  100. GRB 230805B: Swift/UVOT Upper Limits

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