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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"

19603 results found.

  1. GRB 231017A: LCOGT Optical Upper Limits
  2. GRB231017A: GROWTH-India upper limits on the optical afterglow
  3. GRB 231017A: Fermi GBM Detection
  4. GRB 231017A: Swift-XRT observations
  5. GRB 231017A: Swift ToO observations
  6. GRB 231017A: Swift/BAT-GUANO candidate arcminute localization of a burst
  7. LIGO/Virgo/KAGRA S231014r: Upper limits from Swift/BAT-GUANO
  8. LIGO/Virgo/KAGRA S231005j: Upper limits from Swift/BAT-GUANO
  9. LIGO/Virgo/KAGRA S231001aq: Upper limits from Swift/BAT-GUANO
  10. LIGO/Virgo/KAGRA S230930al: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S230928cb: Upper limits from Swift/BAT-GUANO
  12. NuEm-230927A: Swift-XRT follow-up
  13. Swift Triggers 1192745 and 1192747 are not astrophysical events
  14. Swift Triggers 1192740, 1192742 and 1192743 are not astrophysical events
  15. Swift Triggers 1192735 and 1192737 are not astrophysical events
  16. Konus-Wind detection of GRB 230919A
  17. LIGO/Virgo/KAGRA S230924an: Upper limits from Swift/BAT-GUANO
  18. LIGO/Virgo/KAGRA S230920al: Upper limits from Swift/BAT-GUANO
  19. LIGO/Virgo/KAGRA S230919bj: Upper limits from Swift/BAT-GUANO
  20. LIGO/Virgo/KAGRA S230917af: GRAWITA wide-field observations
  21. LIGO/Virgo/KAGRA S230917af: Zwicky Transient Facility observations
  22. IPN triangulation of GRB 230919A (short)
  23. GRB 230919A: Fermi GBM Observation
  24. GRB 230919A: Swift/BAT-GUANO detection of a possibly short burst outside the coded FOV
  25. LIGO/Virgo S230917af: Swift XRT observations, 6 X-ray sources
  26. GRB 230915A: Fermi GBM observation
  27. Swift Triggers 1192480, 1192481, 1192482 and 1192483 are not astrophysical events
  28. GRB 230911A: Fermi GBM Observation
  29. Swift GRB230916.18: Global MASTER-Net observations report
  30. GRB 230915A: Swift/BAT-GUANO detection of a burst
  31. LIGO/Virgo/KAGRA S230914ak: Upper limits from Swift/BAT-GUANO
  32. Swift GRB230916.19: Global MASTER-Net observations report
  33. Swift GRB230916.18: Global MASTER-Net observations report
  34. Swift Triggers 1192234, 1192235 and 1192236 are not astrophysical events
  35. Swift GRB230916.13: Global MASTER-Net observations report
  36. Swift GRB230916.12: Global MASTER-Net observations report
  37. Swift GRB230916.11: Global MASTER-Net observations report
  38. Swift Trigger 1192233 is not a GRB
  39. GRB 230911A: Swift-XRT afterglow detection
  40. GRB 230913A: CALET Gamma-Ray Burst Monitor detection
  41. Swift Trigger 1192088 is not an astrophysical event
  42. GRB 230913A: Glowbug gamma-ray detection
  43. Swift Trigger 1191994 is not an astrophysical event
  44. Swift GRB230913.70: Global MASTER-Net observations report
  45. GRB 230913A: Fermi GBM Observation
  46. Swift Trigger 1191904 is not a GRB
  47. Swift GRB230913.70: Global MASTER-Net observations report
  48. Swift Trigger 1191903 is not an astrophysical event
  49. GRB 230911A: Swift ToO observations
  50. GRB 230913A: Swift/BAT-GUANO arcminute localization of a burst
  51. GRB 230908A: CALET Gamma-Ray Burst Monitor detection
  52. GRB 230911C: Swift-XRT refined Analysis
  53. GRB 230911C: Swift-BAT refined analysis
  54. GRB230911C: BOOTES-6/DPRT optical upper limit
  55. GRB 230906A: Chandra detection of the X-ray afterglow
  56. Swift GRB 230911C: Global MASTER-Net observations report
  57. IPN triangulation of GRB 230911D (long)
  58. GRB 230911D: Fermi-LAT detection
  59. GRB230911C: LCOGT Optical Upper Limits
  60. GRB 230911C: Swift/UVOT Upper Limits
  61. GRB 230908A: Swift/BAT-GUANO detection of a long burst outside the coded FOV
  62. GRB 230911C: Enhanced Swift-XRT position
  63. GRB 230911C: Swift detection of a burst
  64. GRB 230906A: BlackGEM upper limits
  65. GRB 230903A: TESS observations of optical emission
  66. GRB 230906A: Swift/UVOT Upper Limits
  67. GRID detection of GRB 230827A
  68. GRB 230906A: Swift-XRT observations
  69. IPN triangulation of GRB 230906A (short)
  70. GRB 230906A: Swift ToO observations
  71. Swift Attitude Control Affecting Some UVOT Images
  72. GRB 230903A: Swift-XRT refined Analysis
  73. GRB 230903A: Enhanced Swift-XRT position
  74. GRB 230903A: VLT/X-shooter optical observations
  75. GRB 230903A: Swift-BAT refined analysis
  76. GRB 230903A: Fermi GBM detection
  77. GRB 230903A: LCOGT Optical Upper Limits
  78. GRB 230903A: Swift detection of a burst
  79. Swift GRB230903.72: Global MASTER-Net observations report
  80. GRB 230827A: Glowbug gamma-ray detection
  81. GRB 230826A: Glowbug gamma-ray detection
  82. GRB 230827B: Swift-XRT afterglow detection
  83. GRB 230827B: Swift ToO observations
  84. GRB 230827A: Fermi GBM Observation
  85. GRB 230826A: Swift-BAT refined analysis
  86. Swift Trigger 1188089 is not a GRB
  87. GRB 230827A: VZLUSAT-2 detection
  88. GRB 230827A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  89. GRB 230826A: VZLUSAT-2 detection
  90. Subject: GRB230826A: Swift/UVOT upper limits
  91. Swift J1727.8-1613 (GRB 230824A): Osservatorio Astronomico "Nastro Verde" optical observations
  92. Swift J1727.8-1613 (GRB 230824A): Montarrenti Observatory photometric observations
  93. GRB 230826A: GRBAlpha detection
  94. GRB 230826A: Fermi GBM Observation
  95. Swift J1727.8-1613 (GRB 230824A): Leavitt Observatory optical observations
  96. GRB 230826A: Enhanced Swift-XRT position
  97. GRB 230826A: Swift-XRT refined Analysis
  98. GRB 230826A: Mondy optical observations
  99. Swift J1727.8-1613 (GRB 230824A): GAD Observatory La Spezia - optical observations
  100. GRB 230826A: Swift detection of a burst

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