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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"

36147 results found.

  1. GRB 230824A: Swift detection of a burst
  2. Swift Trigger 1186908 is not a GRB
  3. GRB 230822A: Fermi GBM Observation
  4. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  5. GRB 230822A: Swift/BAT-GUANO detection of a burst
  6. IceCube-230823A: Event likely due to background
  7. GRB 230812B: AstroSat LAXPC detection
  8. GRB 230818B: VZLUSAT-2 detection
  9. GRB 230818B: AstroSat CZTI detection
  10. GRID detection of GRB 230818A
  11. GRB 230822A: Fermi GBM Final Real-time Localization
  12. GRB 230812B: Assy optical observations, possible SN rise
  13. GRB 230815A: ATCA detection of radio counterpart
  14. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  15. GRB 230818A: Swift-BAT refined analysis
  16. GRB 20230818A: GIT optical upper limit
  17. Swift Trigger 1186391 is not a GRB
  18. Swift Trigger 1186390 is not a GRB
  19. Konus-Wind detection of GRB 230818A
  20. Swift Trigger 1186386 is not a GRB
  21. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  22. GRB 230820A: AstroSat CZTI detection
  23. GRB 230818A: Fermi GBM Observation
  24. GRB 230812B: GIT Confirmation of SN rise
  25. GRB 230818A: Nickel and KAIT telescope optical observations
  26. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  27. GRB 230812B: SAO RAS Zeiss-1000 observations
  28. GRB 230818A: further SAO RAS Zeiss-1000 observations
  29. GRB 230818A: AKO Upper Limit
  30. GRB 230818A: AstroSat CZTI detection
  31. GRB 230818A: Tautenburg observations
  32. GRB 230818A: Leavitt Observatory upper limit
  33. GRB 230818A: Swift-XRT refined Analysis
  34. GRB 230818A: Bassano Bresciano Observatory optical observations
  35. GRB 230818A: KGO RC-25 optical observations
  36. GRB 230818A: Swift/UVOT Detection
  37. GRB 230818A: NOT photometry and spectroscopy
  38. GRB 230818A: Enhanced Swift-XRT position
  39. GRB 230818A: SAO RAS Zeiss-1000 observations
  40. Fermi GRB 230818A: Global MASTER-Net observations report
  41. GRB 230818A: GOTO optical afterglow detection
  42. GRB 230818A: Swift detection of a burst
  43. GRB 230818A: Fermi GBM Final Real-time Localization
  44. GRB 230812B: SAO RAS observations, possible re-brightening
  45. GRB 230816A: Swift-BAT refined analysis
  46. GRB 230816A: SVOM/C-GFT optical detection
  47. GRB 230817A: AstroSat CZTI detection
  48. GRB 230812B: SAO RAS optical observations
  49. GRB 230816A: Swift-XRT refined Analysis
  50. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  51. GRB 230812B: NOEMA detection
  52. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  53. Fermi GRB 230817A: Global MASTER-Net observations report
  54. GRB 230817A: BALROG localization (Fermi Trigger 713966581 / GRB 230817502)
  55. GRB 230817A: Fermi GBM Final Real-time Localization
  56. GRB 230812B: optical photometry from Konkoly
  57. GRB 230816A: Enhanced Swift-XRT position
  58. GRB 230812B: SAO RAS optical observations
  59. GRB230816A: Possible host and GIT detection of optical counterpart
  60. GRB 230816A: Tautenburg observations
  61. GRB 230816A: AKO Optical Observations
  62. GRB 230816A: TShAO and Assy optical observations
  63. GRB 230816A: SAO RAS optical observations
  64. IPN triangulation of GRB 230815B
  65. GRB 230816A: Nanshan/HMT optical afterglow detection
  66. GRB 230815A: SOAR/Goodman follow-up imaging
  67. GRB 230816A: Swift detection of a burst
  68. GRB 230815A: Swift-BAT refined analysis
  69. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  70. GRB 230815B: AstroSat CZTI detection
  71. GRB230815A: Swift/UVOT upper limits
  72. GRB 230812B: GAD Observatory optical observations (upper limit)
  73. GRB 230815A: Swift-XRT refined Analysis
  74. GRB 230812B: iTelescope optical upper limit
  75. GRB 230812B: continued SAO RAS optical observation
  76. GRB230815A: BOOTES-6/DPRT optical upper limit
  77. GRB 230815A: Fermi GBM detection
  78. Swift GRB 230815A: Global MASTER-Net observations report
  79. Fermi GRB 230814A: Global MASTER-Net observations report
  80. GRB 230815A: Enhanced Swift-XRT position
  81. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  82. GRB 230812B: Tautenburg observations
  83. GRB 230815A: Swift detection of a burst
  84. GRB 230812B: AMI-LA radio detection of afterglow candidate
  85. GRB 230812B: continued AbAO optical afterglow observations
  86. GRB 230812B: Optical observaions from Rozhen Observatory
  87. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  88. GRB 230812B: further SAO RAS optical observations
  89. GRB 230812B: Upper limits from a neutrino search with IceCube
  90. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  91. GRB 230814A: BALROG localization (Fermi Trigger 713732101 / GRB 230814788)
  92. GRB 230812B: CrAO ZTSh optical observations
  93. GRB 230814A: Fermi GBM Final Real-time Localization
  94. GRB 230812B: Koshka Zeiss-1000 optical observations
  95. GRB 230812B: GIT optical follow-up
  96. GRB 230812B: Leavitt Observatory optical observations
  97. GRB 230812B : optical observations from Observatoire de Haute-Provence
  98. GRB 230812B: Bassano Bresciano Observatory optical observations
  99. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  100. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation

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