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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"

12095 results found.

  1. GRB 230903A: Swift detection of a burst
  2. Swift GRB230903.72: Global MASTER-Net observations report
  3. GRB 230828A: AstroSat CZTI detection
  4. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  5. Fermi trigger No 714809315: Global MASTER-Net observations report
  6. Fermi GRB 230827A: Global MASTER-Net observations report
  7. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  8. GRB 230826A: Mondy optical observations
  9. Swift GRB230826.81: Global MASTER-Net observations report
  10. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  11. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  12. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  13. Trigger 1187203: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  14. Trigger 1187142: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  15. MAXI/GSC detection of Swift J1727.8-1613 (GRB 230824A)
  16. IBAS trigger 10375 is not a GRB
  17. Integral GRB230824.72: Global MASTER-Net observations report
  18. GRB 230824B: AstroSat CZTI detection
  19. GRB 230824A: Swift detection of a burst
  20. LIGO/Virgo/KAGRA S230822bm: Upper limits from Swift/BAT-GUANO
  21. GRB 230818B: AstroSat CZTI detection
  22. GRB 230812B: Assy optical observations, possible SN rise
  23. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  24. Konus-Wind detection of GRB 230818A
  25. GRB 230820A: AstroSat CZTI detection
  26. LIGO/Virgo/KAGRA S230820bq: Identification of a GW compact binary merger candidate
  27. Swift GRB230820.82: Global MASTER-Net observations report
  28. Swift Triggers 1186280 and 1186291 are not GRBs
  29. GRB 230818A: SAO RAS 6-m telescope spectroscopy
  30. GRB 230818A: AstroSat CZTI detection
  31. Fermi GRB 230818A: Global MASTER-Net observations report
  32. Fermi trigger No 713974668: Global MASTER-Net observations report
  33. Swift GRB230818.98: Global MASTER-Net observations report
  34. GRB 230812B: SAO RAS observations, possible re-brightening
  35. GRB 230817A: AstroSat CZTI detection
  36. GRB 230815A: VLT/HAWK-I near-infrared afterglow detection
  37. GRB 230812B: SAO RAS optical observations
  38. GRB 230816A: Tautenburg observations
  39. GRB 230816A: AKO Optical Observations
  40. GRB 230816A: TShAO and Assy optical observations
  41. Swift GRB230816.80: Global MASTER-Net observations report
  42. GRB 230816A: Nanshan/HMT optical afterglow detection
  43. GRB 230815B: GECAM-B and GECAM-C detection of a burst
  44. GRB 230815B: AstroSat CZTI detection
  45. GRB 230812B: continued SAO RAS optical observation
  46. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  47. GRB 230812B: further SAO RAS optical observations
  48. GRB 230812B: GIT optical follow-up
  49. GRB 230812B: Leavitt Observatory optical observations
  50. GRB 230812B : optical observations from Observatoire de Haute-Provence
  51. GRB 230812B: Montarrenti Observatory optical observations
  52. GRB 230812B: SAO RAS optical observations
  53. Konus-Wind detection of GRB 230812B
  54. GRB 230812B: GECAM-C observation of a very bright burst
  55. GRB 230812B: Swift-XRT afterglow detection
  56. GRB 230812B: Improved Swift/XRT localization
  57. GRB 230812B: Fermi-LAT detection
  58. Fermi GRB 230812B: Global MASTER-Net observations report
  59. GRB 230812B: Fermi GBM detection of an extremely bright GRB
  60. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  61. GRB 230805B: AstroSat CZTI detection
  62. Fermi trigger No 713136868: Global MASTER-Net observations report
  63. The Fermi GBM Trigger 713134237 / 230807868 is not associated with LIGO/Virgo/KAGRA S230807f.
  64. LIGO/Virgo/KAGRA S230807f: Identification of a GW compact binary merger candidate
  65. LIGO/Virgo/KAGRA S230805x: Upper limits from Swift/BAT-GUANO
  66. Konus-Wind detection of GRB 230803A
  67. GRB 230805B : OHP/T193 optical upper limit
  68. LIGO/Virgo/KAGRA S230806ak: Identification of a GW compact binary merger candidate
  69. GRB 230805B: Bassano Bresciano observatory upper limit
  70. GRB 230805B: BOOTES-6/DPRT optical upper limit and 1.5m OSN detection
  71. GRB 230805B: Swift-XRT refined Analysis
  72. GRB 230805B: Swift detection of a burst
  73. GRB 230802B: AstroSat CZTI detection
  74. IPN triangulation of GRB 230803A
  75. GRB 230803A: AstroSat CZTI detection
  76. LIGO/Virgo/KAGRA S230802aq: AstroSat CZTI non-detection and upper limits
  77. Fermi trigger No 712713532: Global MASTER-Net observations report
  78. LIGO/Virgo/KAGRA S230802aq: Coverage and upper limits from MAXI/GSC observations
  79. LIGO/Virgo/KAGRA S230731an: Upper limits from Swift/BAT-GUANO
  80. LIGO/Virgo/KAGRA S230731an: AstroSat CZTI non-detection and upper limits
  81. LIGO/Virgo/KAGRA S230731an: Coverage and upper limits from MAXI/GSC observations
  82. Fermi-LAT gamma-ray observations of IceCube-230727A
  83. GRB 230728A: Fermi GBM Observation
  84. GRB 230728A: Swift-XRT refined Analysis
  85. GRB 230727A: AstroSat CZTI detection
  86. GRB 230728A: Swift detection of a burst
  87. Fermi-LAT gamma-ray observations of IceCube-230725A
  88. Fermi-LAT gamma-ray observations of IceCube-230724A
  89. Konus-Wind detection of GRB 230723A
  90. GRB 230723B: MITSuME Akeno optical afterglow candidate detection
  91. Integral GRB230725.99: Global MASTER-Net observations report
  92. IceCube Alert 230725.90: Global MASTER-Net observations report
  93. GRB 230723B: Osservatorio Astronomico Nastro Verde upper limit
  94. GRB 230723B: Optical afterglow candidate from CAHA
  95. GRB 230723B: Swift-XRT refined Analysis
  96. GRB 230723B: non-detections from Observatoire de Haute-Provence
  97. IceCube Alert 230724.08: Global MASTER-Net observations report
  98. Fermi trigger No 711853834: Global MASTER-Net observations report
  99. GRB 230723B: Optical limit from CAHA
  100. Swift-XRT position for GRB 230723B

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