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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"

27779 results found.

  1. Swift GRB230821.64: Global MASTER-Net observations report
  2. GRB 230818A: Swift-BAT refined analysis
  3. GRB 20230818A: GIT optical upper limit
  4. Swift Trigger 1186391 is not a GRB
  5. Swift Trigger 1186390 is not a GRB
  6. Konus-Wind detection of GRB 230818A
  7. Swift Trigger 1186386 is not a GRB
  8. Swift triggers 1186294-1186304 are not astrophysical transients
  9. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  10. Swift GRB230820.81: Global MASTER-Net observations report
  11. Swift GRB230820.80: Global MASTER-Net observations report
  12. GRB 230820A: AstroSat CZTI detection
  13. Swift GRB230820.82: Global MASTER-Net observations report
  14. Swift Triggers 1186280 and 1186291 are not GRBs
  15. GRB 230818A: Fermi GBM Observation
  16. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  17. GRB 230818A: AKO Upper Limit
  18. GRB 230818A: AstroSat CZTI detection
  19. GRB 230818A: Leavitt Observatory upper limit
  20. GRB 230818A: Swift-XRT refined Analysis
  21. GRB 230818A: Bassano Bresciano Observatory optical observations
  22. GRB 230818A: KGO RC-25 optical observations
  23. GRB 230818A: Swift/UVOT Detection
  24. GRB 230818A: NOT photometry and spectroscopy
  25. GRB 230818A: Enhanced Swift-XRT position
  26. GRB 230818A: GOTO optical afterglow detection
  27. GRB 230818A: Swift detection of a burst
  28. GRB 230818A: Fermi GBM Final Real-time Localization
  29. Swift GRB230818.98: Global MASTER-Net observations report
  30. Swift GRB230818.98: Global MASTER-Net OT detection
  31. GRB 230816A: Swift-BAT refined analysis
  32. GRB 230816A: SVOM/C-GFT optical detection
  33. GRB 230817A: AstroSat CZTI detection
  34. GRB 230816A: Swift-XRT refined Analysis
  35. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  36. GRB 230812B: NOEMA detection
  37. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  38. GRB 230817A: Fermi GBM Final Real-time Localization
  39. GRB 230812B: optical photometry from Konkoly
  40. GRB 230816A: Enhanced Swift-XRT position
  41. GRB230816A: Possible host and GIT detection of optical counterpart
  42. Swift GRB230816.80: Global MASTER-Net observations report
  43. IPN triangulation of GRB 230815B
  44. GRB 230816A: Nanshan/HMT optical afterglow detection
  45. GRB 230815A: SOAR/Goodman follow-up imaging
  46. Swift GRB230816.67: Global MASTER-Net observations report
  47. GRB 230816A: Swift detection of a burst
  48. GRB 230815A: Swift-BAT refined analysis
  49. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  50. GRB 230815B: AstroSat CZTI detection
  51. GRB230815A: Swift/UVOT upper limits
  52. GRB 230812B: GAD Observatory optical observations (upper limit)
  53. GRB 230815A: Swift-XRT refined Analysis
  54. GRB 230812B: iTelescope optical upper limit
  55. GRB230815A: BOOTES-6/DPRT optical upper limit
  56. GRB 230815A: Fermi GBM detection
  57. Swift GRB 230815A: Global MASTER-Net observations report
  58. GRB 230815A: Enhanced Swift-XRT position
  59. GRB 230815A: Swift detection of a burst
  60. GRB 230812B: AMI-LA radio detection of afterglow candidate
  61. GRB 230812B: Optical observaions from Rozhen Observatory
  62. GRB 230812B: Upper limits from a neutrino search with IceCube
  63. GRB 230814A: Fermi GBM Final Real-time Localization
  64. GRB 230812B: GIT optical follow-up
  65. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  66. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  67. GRB 230812B: OASDG optical observations
  68. GRB 230812B: Detected Optical Afterglow Candidate
  69. Konus-Wind detection of GRB 230812B
  70. GRB230812B: AGILE/MCAL detection
  71. GRB 230812B: Swift-XRT afterglow detection
  72. GRB 230812: Swift/UVOT Detection
  73. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  74. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  75. Fermi GRB 230812B: MASTER optical counterpart
  76. GRB 230812B: KAIT Optical Afterglow Candidate
  77. GRB 230812B: Improved Swift/XRT localization
  78. GRB 230812B: Preliminary Swift/XRT localization
  79. GRB 230812B: Fermi-LAT detection
  80. GRB 230812B: Tiled Swift observations
  81. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  82. GRB 230812B: Fermi GBM Final Real-time Localization
  83. GRB 230812A: Fermi GBM Final Real-time Localization
  84. GRB 230808A: Fermi GBM Detection
  85. GRB 230805B: Swift-BAT refined analysis
  86. LIGO/Virgo/KAGRA S230810af: Retraction of GW compact binary merger candidate
  87. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  88. GRB 230805B: AstroSat CZTI detection
  89. GRB 230808A: Swift/BAT-GUANO detection of a burst
  90. GRB 230808B: Fermi GBM Final Real-time Localization
  91. GRB 230808A: Fermi GBM Final Real-time Localization
  92. GRB 230805B : MITSuME Akeno optical upper limits
  93. GRB 230807A: Fermi GBM Final Real-time Localization
  94. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  95. Konus-Wind detection of GRB 230803A
  96. GRB 230805B: Fermi GBM observation
  97. GRB 230806A: Fermi GBM Final Localization
  98. GRB 230805B: Enhanced Swift-XRT position
  99. GRB 230805B: Swift/UVOT Upper Limits
  100. GRB 230805B: Bassano Bresciano observatory upper limit

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