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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"
  1. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  2. GRB 230812B: NOEMA detection
  3. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  4. Fermi GRB 230817A: Global MASTER-Net observations report
  5. GRB 230817A: BALROG localization (Fermi Trigger 713966581 / GRB 230817502)
  6. GRB 230817A: Fermi GBM Final Real-time Localization
  7. GRB 230812B: optical photometry from Konkoly
  8. GRB 230816A: Enhanced Swift-XRT position
  9. GRB 230812B: SAO RAS optical observations
  10. GRB230816A: Possible host and GIT detection of optical counterpart
  11. GRB 230816A: Tautenburg observations
  12. GRB 230816A: AKO Optical Observations
  13. GRB 230816A: TShAO and Assy optical observations
  14. GRB 230816A: SAO RAS optical observations
  15. Swift GRB230816.80: Global MASTER-Net observations report
  16. IPN triangulation of GRB 230815B
  17. GRB 230816A: Nanshan/HMT optical afterglow detection
  18. GRB 230815A: SOAR/Goodman follow-up imaging
  19. Swift GRB230816.67: Global MASTER-Net observations report
  20. GRB 230816A: Swift detection of a burst
  21. GRB 230815A: Swift-BAT refined analysis
  22. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  23. GRB 230815B: AstroSat CZTI detection
  24. GRB230815A: Swift/UVOT upper limits
  25. GRB 230812B: GAD Observatory optical observations (upper limit)
  26. GRB 230815A: Swift-XRT refined Analysis
  27. GRB 230812B: iTelescope optical upper limit
  28. GRB 230812B: continued SAO RAS optical observation
  29. GRB230815A: BOOTES-6/DPRT optical upper limit
  30. GRB 230815A: Fermi GBM detection
  31. Swift GRB 230815A: Global MASTER-Net observations report
  32. Fermi GRB 230814A: Global MASTER-Net observations report
  33. GRB 230815A: Enhanced Swift-XRT position
  34. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  35. GRB 230812B: Tautenburg observations
  36. GRB 230815A: Swift detection of a burst
  37. GRB 230812B: AMI-LA radio detection of afterglow candidate
  38. GRB 230812B: continued AbAO optical afterglow observations
  39. GRB 230812B: Optical observaions from Rozhen Observatory
  40. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  41. LIGO/Virgo/KAGRA S230814ah: Identification of a GW compact binary merger candidate
  42. GRB 230812B: further SAO RAS optical observations
  43. GRB 230812B: Upper limits from a neutrino search with IceCube
  44. LIGO/Virgo/KAGRA S230814r: Updated Sky localization
  45. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  46. GRB 230814A: BALROG localization (Fermi Trigger 713732101 / GRB 230814788)
  47. GRB 230812B: CrAO ZTSh optical observations
  48. GRB 230814A: Fermi GBM Final Real-time Localization
  49. GRB 230812B: Koshka Zeiss-1000 optical observations
  50. GRB 230812B: GIT optical follow-up
  51. GRB 230812B: Leavitt Observatory optical observations
  52. GRB 230812B : optical observations from Observatoire de Haute-Provence
  53. GRB 230812B: Bassano Bresciano Observatory optical observations
  54. GRB 230812B: Faulkes Telescope North optical afterglow follow-up
  55. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  56. GRB 230812B: rest-frame energetics from Konus-Wind observation
  57. GRB 230812B: OASDG optical observations
  58. GRB 230812B: AbAO optical observations
  59. LIGO/Virgo/KAGRA S230814r: Identification of a GW compact binary merger candidate
  60. GRB 230812B: Spectroscopy from NOT
  61. GRB 230812B: Redshift from OSIRIS+/GTC
  62. GRB 230812B: Montarrenti Observatory optical observations
  63. LIGO/Virgo/KAGRA S230812aj: two counterpart neutrino candidates from IceCube neutrino searches
  64. GRB 230812B: SAO RAS optical observations
  65. GRB 230812B: Detected Optical Afterglow Candidate
  66. GRB 230812B: GMG - GRANDMA observations
  67. Konus-Wind detection of GRB 230812B
  68. GRB230812B: AGILE/MCAL detection
  69. GRB 230812B: GECAM-C observation of a very bright burst
  70. GRB 230812B: Swift-XRT afterglow detection
  71. GRB 230812: Swift/UVOT Detection
  72. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  73. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  74. Fermi GRB 230812B: MASTER optical counterpart
  75. GRB 230812B: KAIT Optical Afterglow Candidate
  76. GRB 230812B: Improved Swift/XRT localization
  77. GRB 230812B: Preliminary Swift/XRT localization
  78. GRB 230812B: Fermi-LAT detection
  79. GRB 230812B: Fermi GBM Observation of a very bright burst
  80. LAT GRB230812.79: Global MASTER-Net observations report
  81. Fermi GRB 230812B: Global MASTER-Net observations report
  82. GRB 230812B: Tiled Swift observations
  83. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  84. GRB 230812B: Fermi GBM Final Real-time Localization
  85. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  86. Fermi trigger No 713525317: Global MASTER-Net observations report
  87. GRB 230812A: Fermi GBM Final Real-time Localization
  88. LIGO/Virgo/KAGRA S230811n: Updated Sky localization
  89. GRB 230808A: Fermi GBM Detection
  90. LIGO/Virgo/KAGRA S230811n: Identification of a GW compact binary merger candidate
  91. GRB 230805B: Swift-BAT refined analysis
  92. LIGO/Virgo/KAGRA S230810af: Retraction of GW compact binary merger candidate
  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. Fermi trigger No 713136868: Global MASTER-Net observations report
  97. GRB 230808B: Fermi GBM Final Real-time Localization
  98. The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f.
  99. Fermi trigger No 713205976: Global MASTER-Net observations report
  100. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova

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