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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"

22063 results found.

  1. Swift GRB230824.10: Global MASTER-Net observations report
  2. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  3. GRB 230822A: Swift/BAT-GUANO detection of a burst
  4. IceCube-230823A: Event likely due to background
  5. GRB 230812B: Assy optical observations, possible SN rise
  6. GRB 230815A: ATCA detection of radio counterpart
  7. Swift GRB230821.64: Global MASTER-Net observations report
  8. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  9. GRB 20230818A: GIT optical upper limit
  10. Konus-Wind detection of GRB 230818A
  11. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  12. Swift GRB230820.81: Global MASTER-Net observations report
  13. Swift GRB230820.80: Global MASTER-Net observations report
  14. Swift GRB230820.82: Global MASTER-Net observations report
  15. GRB 230818A: Nickel and KAIT telescope optical observations
  16. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  17. GRB 230812B: SAO RAS Zeiss-1000 observations
  18. GRB 230818A: further SAO RAS Zeiss-1000 observations
  19. GRB 230818A: Tautenburg observations
  20. GRB 230818A: Leavitt Observatory upper limit
  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: SAO RAS Zeiss-1000 observations
  26. Fermi GRB 230818A: Global MASTER-Net observations report
  27. Fermi trigger No 713974668: Global MASTER-Net observations report
  28. GRB 230818A: GOTO optical afterglow detection
  29. Swift GRB230818.98: Global MASTER-Net observations report
  30. GRB 230812B: SAO RAS observations, possible re-brightening
  31. GRB 230812B: SAO RAS optical observations
  32. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  33. GRB 230812B: NOEMA detection
  34. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  35. Fermi GRB 230817A: Global MASTER-Net observations report
  36. GRB 230812B: SAO RAS optical observations
  37. GRB230816A: Possible host and GIT detection of optical counterpart
  38. GRB 230816A: Tautenburg observations
  39. GRB 230816A: AKO Optical Observations
  40. GRB 230816A: TShAO and Assy optical observations
  41. GRB 230816A: SAO RAS optical observations
  42. Swift GRB230816.80: Global MASTER-Net observations report
  43. GRB 230816A: Nanshan/HMT optical afterglow detection
  44. GRB 230815A: SOAR/Goodman follow-up imaging
  45. Swift GRB230816.67: Global MASTER-Net observations report
  46. GRB230815A: Swift/UVOT upper limits
  47. GRB 230812B: GAD Observatory optical observations (upper limit)
  48. Swift GRB 230815A: Global MASTER-Net observations report
  49. Fermi GRB 230814A: Global MASTER-Net observations report
  50. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  51. GRB 230812B: Tautenburg observations
  52. GRB 230812B: AMI-LA radio detection of afterglow candidate
  53. GRB 230812B: continued AbAO optical afterglow observations
  54. GRB 230812B: Optical observaions from Rozhen Observatory
  55. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  56. GRB 230812B: further SAO RAS optical observations
  57. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  58. GRB 230812B: CrAO ZTSh optical observations
  59. GRB 230812B: Koshka Zeiss-1000 optical observations
  60. GRB 230812B: Leavitt Observatory optical observations
  61. GRB 230812B : optical observations from Observatoire de Haute-Provence
  62. GRB 230812B: Bassano Bresciano Observatory optical observations
  63. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  64. GRB 230812B: OASDG optical observations
  65. GRB 230812B: AbAO optical observations
  66. GRB 230812B: Montarrenti Observatory optical observations
  67. GRB 230812B: SAO RAS optical observations
  68. GRB 230812B: GMG - GRANDMA observations
  69. Konus-Wind detection of GRB 230812B
  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. Fermi GRB 230812B: MASTER optical counterpart
  74. GRB 230812B: KAIT Optical Afterglow Candidate
  75. LAT GRB230812.79: Global MASTER-Net observations report
  76. Fermi GRB 230812B: Global MASTER-Net observations report
  77. GRB 230812B: Tiled Swift observations
  78. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  79. Fermi trigger No 713525317: Global MASTER-Net observations report
  80. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  81. GRB 230808A: Swift/BAT-GUANO detection of a burst
  82. Fermi trigger No 713136868: Global MASTER-Net observations report
  83. Fermi trigger No 713205976: Global MASTER-Net observations report
  84. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  85. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  86. Fermi GRB 230807A: Global MASTER-Net observations report
  87. Fermi trigger No 713134237: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  89. Konus-Wind detection of GRB 230803A
  90. GRB 230805B : OHP/T193 optical upper limit
  91. GRB 230805B: Swift/UVOT Upper Limits
  92. Fermi trigger No 712991593: Global MASTER-Net observations report
  93. GRB 230805B: Bassano Bresciano observatory upper limit
  94. Fermi trigger No 712987357: Global MASTER-Net observations report
  95. GRB 230805B: NOT optical afterglow confirmation
  96. Fermi GRB 230805A: Global MASTER-Net observations report
  97. GRB 230805B: SAO RAS optical observations
  98. Fermi trigger No 712927418: Global MASTER-Net observations report
  99. Swift GRB 230805B: Global MASTER-Net observations report
  100. Fermi trigger No 712798043: Global MASTER-Net observations report

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