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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"

19600 results found.

  1. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  2. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  3. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  4. NuEm-230927A: Swift-XRT follow-up
  5. Swift Triggers 1192745 and 1192747 are not astrophysical events
  6. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  7. Swift Triggers 1192735 and 1192737 are not astrophysical events
  8. Konus-Wind detection of GRB 230919A
  9. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  12. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  13. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  14. IPN triangulation of GRB 230919A (short)
  15. GRB 230919A: Fermi GBM Observation
  16. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  17. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  18. GRB 230915A: Fermi GBM observation
  19. Swift Triggers 1192480, 1192481, 1192482 and 1192483 are not astrophysical events
  20. GRB 230911A: Fermi GBM Observation
  21. Swift GRB230916.18: Global MASTER-Net observations report
  22. GRB 230915A: Swift/BAT-GUANO detection of a burst
  23. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  24. Swift GRB230916.19: Global MASTER-Net observations report
  25. Swift GRB230916.18: Global MASTER-Net observations report
  26. Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
  27. Swift GRB230916.13: Global MASTER-Net observations report
  28. Swift GRB230916.12: Global MASTER-Net observations report
  29. Swift GRB230916.11: Global MASTER-Net observations report
  30. Swift Trigger 1192233 is not a GRB
  31. GRB 230911A: Swift-XRT afterglow detection
  32. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  33. Swift Trigger 1192088 is not an astrophysical event
  34. GRB 230913A: Glowbug gamma-ray detection
  35. Swift Trigger 1191994 is not an astrophysical event
  36. Swift GRB230913.70: Global MASTER-Net observations report
  37. GRB 230913A: Fermi GBM Observation
  38. Swift Trigger 1191904 is not a GRB
  39. Swift GRB230913.70: Global MASTER-Net observations report
  40. Swift Trigger 1191903 is not an astrophysical event
  41. GRB 230911A: Swift ToO observations
  42. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  43. GRB 230908A: CALET Gamma-Ray Burst Monitor detection
  44. GRB 230911C: Swift-XRT refined Analysis
  45. GRB 230911C: Swift-BAT refined analysis
  46. GRB230911C: BOOTES-6/DPRT optical upper limit
  47. GRB 230906A: Chandra detection of the X-ray afterglow
  48. Swift GRB 230911C: Global MASTER-Net observations report
  49. IPN triangulation of GRB 230911D (long)
  50. GRB 230911D: Fermi-LAT detection
  51. GRB230911C: LCOGT Optical Upper Limits
  52. GRB 230911C: Swift/UVOT Upper Limits
  53. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  54. GRB 230911C: Enhanced Swift-XRT position
  55. GRB 230911C: Swift detection of a burst
  56. GRB 230906A: BlackGEM upper limits
  57. GRB 230903A: TESS observations of optical emission
  58. GRB 230906A: Swift/UVOT Upper Limits
  59. GRID detection of GRB 230827A
  60. GRB 230906A: Swift-XRT observations
  61. IPN triangulation of GRB 230906A (short)
  62. GRB 230906A: Swift ToO observations
  63. Swift Attitude Control Affecting Some UVOT Images
  64. GRB 230903A: Swift-XRT refined Analysis
  65. GRB 230903A: Enhanced Swift-XRT position
  66. GRB 230903A: VLT/X-shooter optical observations
  67. GRB 230903A: Swift-BAT refined analysis
  68. GRB 230903A: Fermi GBM detection
  69. GRB 230903A: LCOGT Optical Upper Limits
  70. GRB 230903A: Swift detection of a burst
  71. Swift GRB230903.72: Global MASTER-Net observations report
  72. GRB 230827A: Glowbug gamma-ray detection
  73. GRB 230826A: Glowbug gamma-ray detection
  74. GRB 230827B: Swift-XRT afterglow detection
  75. GRB 230827B: Swift ToO observations
  76. GRB 230827A: Fermi GBM Observation
  77. GRB 230826A: Swift-BAT refined analysis
  78. Swift Trigger 1188089 is not a GRB
  79. GRB 230827A: VZLUSAT-2 detection
  80. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  81. GRB 230826A: VZLUSAT-2 detection
  82. Subject: GRB230826A: Swift/UVOT upper limits
  83. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  84. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  85. GRB 230826A: GRBAlpha detection
  86. GRB 230826A: Fermi GBM Observation
  87. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  88. GRB 230826A: Enhanced Swift-XRT position
  89. GRB 230826A: Swift-XRT refined Analysis
  90. GRB 230826A: Mondy optical observations
  91. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  92. GRB 230826A: Swift detection of a burst
  93. Swift GRB230826.81: Global MASTER-Net observations report
  94. Swift J1727.8-1613 (GRB 230824A): Bassano Bresciano Observatory optical observations
  95. GRB 230824A: AKO Photometric Follow-up Observations
  96. LIGO/Virgo/KAGRA S230825k: Upper limits from Swift/BAT-GUANO
  97. Swift GRB230825.85: Global MASTER-Net observations report
  98. Trigger 1187225: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)
  99. Swift J1727.8-1613 (GRB 230824A): Skynet Optical Observations
  100. Trigger 1187207: Swift detection of Swift J1727.8-1613 (AKA GRB 230824A)

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