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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"

21577 results found.

  1. Swift GRB230825.85: Global MASTER-Net observations report
  2. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  3. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  4. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  5. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  6. Swift GRB230825.75: Global MASTER-Net observations report
  7. GRB 230812B: radio detection with the VLA
  8. NICER detection of Swift J1727.8-1613 (GRB 230824A)
  9. Fermi trigger No 714618399: Global MASTER-Net observations report
  10. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  11. GRB 230824A: AKO Optical Afterglow Candidate
  12. GRB 230824A is likely a Galactic Transient: Swift J1727.8-1613
  13. Integral GRB230824.72: Global MASTER-Net observations report
  14. Swift GRB230824.58: Global MASTER-Net observations report
  15. Swift GRB230824.10: Global MASTER-Net observations report
  16. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  17. GRB 230822A: Swift/BAT-GUANO detection of a burst
  18. IceCube-230823A: Event likely due to background
  19. GRB 230812B: Assy optical observations, possible SN rise
  20. GRB 230815A: ATCA detection of radio counterpart
  21. Swift GRB230821.64: Global MASTER-Net observations report
  22. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  23. GRB 20230818A: GIT optical upper limit
  24. Konus-Wind detection of GRB 230818A
  25. GRB 230812B : GRANDMA/Kilonova-Catcher optical afterglow detection and upper limits
  26. Swift GRB230820.81: Global MASTER-Net observations report
  27. Swift GRB230820.80: Global MASTER-Net observations report
  28. Swift GRB230820.82: Global MASTER-Net observations report
  29. GRB 230818A: Nickel and KAIT telescope optical observations
  30. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  31. GRB 230812B: SAO RAS Zeiss-1000 observations
  32. GRB 230818A: further SAO RAS Zeiss-1000 observations
  33. GRB 230818A: Tautenburg observations
  34. GRB 230818A: Leavitt Observatory upper limit
  35. GRB 230818A: Bassano Bresciano Observatory optical observations
  36. GRB 230818A: KGO RC-25 optical observations
  37. GRB 230818A: Swift/UVOT Detection
  38. GRB 230818A: NOT photometry and spectroscopy
  39. GRB 230818A: SAO RAS Zeiss-1000 observations
  40. Fermi GRB 230818A: Global MASTER-Net observations report
  41. Fermi trigger No 713974668: Global MASTER-Net observations report
  42. GRB 230818A: GOTO optical afterglow detection
  43. Swift GRB230818.98: Global MASTER-Net observations report
  44. GRB 230812B: SAO RAS observations, possible re-brightening
  45. GRB 230812B: SAO RAS optical observations
  46. GRB 230816A: Osservatorio Astronomico "Nastro Verde" optical observations
  47. GRB 230812B: NOEMA detection
  48. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  49. Fermi GRB 230817A: Global MASTER-Net observations report
  50. GRB 230812B: SAO RAS optical observations
  51. GRB230816A: Possible host and GIT detection of optical counterpart
  52. GRB 230816A: Tautenburg observations
  53. GRB 230816A: AKO Optical Observations
  54. GRB 230816A: TShAO and Assy optical observations
  55. GRB 230816A: SAO RAS optical observations
  56. Swift GRB230816.80: Global MASTER-Net observations report
  57. GRB 230816A: Nanshan/HMT optical afterglow detection
  58. GRB 230815A: SOAR/Goodman follow-up imaging
  59. Swift GRB230816.67: Global MASTER-Net observations report
  60. GRB230815A: Swift/UVOT upper limits
  61. GRB 230812B: GAD Observatory optical observations (upper limit)
  62. Swift GRB 230815A: Global MASTER-Net observations report
  63. Fermi GRB 230814A: Global MASTER-Net observations report
  64. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  65. GRB 230812B: Tautenburg observations
  66. GRB 230812B: AMI-LA radio detection of afterglow candidate
  67. GRB 230812B: continued AbAO optical afterglow observations
  68. GRB 230812B: Optical observaions from Rozhen Observatory
  69. GRB 230812B: Further Bassano Bresciano Observatory optical observations
  70. GRB 230812B: further SAO RAS optical observations
  71. GRB 230812B: GRANDMA further observations of ZTF23aaxeacr candidate afterglow
  72. GRB 230812B: CrAO ZTSh optical observations
  73. GRB 230812B: Koshka Zeiss-1000 optical observations
  74. GRB 230812B: Leavitt Observatory optical observations
  75. GRB 230812B : optical observations from Observatoire de Haute-Provence
  76. GRB 230812B: Bassano Bresciano Observatory optical observations
  77. GRB 230812B: Osservatorio Astronomico "Nastro Verde" optical observation
  78. GRB 230812B: OASDG optical observations
  79. GRB 230812B: AbAO optical observations
  80. GRB 230812B: Montarrenti Observatory optical observations
  81. GRB 230812B: SAO RAS optical observations
  82. GRB 230812B: GMG - GRANDMA observations
  83. Konus-Wind detection of GRB 230812B
  84. GRB 230812B: Swift-XRT afterglow detection
  85. GRB 230812: Swift/UVOT Detection
  86. GOTO confirmation and possible host galaxy of GRB230812B optical afterglow
  87. Fermi GRB 230812B: MASTER optical counterpart
  88. GRB 230812B: KAIT Optical Afterglow Candidate
  89. LAT GRB230812.79: Global MASTER-Net observations report
  90. Fermi GRB 230812B: Global MASTER-Net observations report
  91. GRB 230812B: Tiled Swift observations
  92. ZTF23aaoohpy/AT2023lcr: JWST spectroscopy confirmation of an associated type Ic-BL supernova
  93. Fermi trigger No 713525317: Global MASTER-Net observations report
  94. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  95. GRB 230808A: Swift/BAT-GUANO detection of a burst
  96. Fermi trigger No 713136868: Global MASTER-Net observations report
  97. Fermi trigger No 713205976: Global MASTER-Net observations report
  98. ZTF23aaoohpy/AT2023lcr: JWST observations consistent with the presence of a supernova
  99. transient SPT-SVJ025406.5-702837: ATCA follow-up observations
  100. Fermi GRB 230807A: Global MASTER-Net observations report

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