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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"
  1. GRB 220521A: Fermi GBM detection
  2. GRB 220521A: Sintesz-Newton/CrAO optical upper limit
  3. GRB 220521A: RATIR Optical and NIR Observations
  4. GRB 220521A: Swift-XRT refined Analysis
  5. GRB 220521A: Swift/UVOT Upper Limits
  6. Fermi GRB 220522A: Global MASTER-Net observations report
  7. Fermi trigger No 674868783: Global MASTER-Net observations report
  8. GRB 220521A: SAO RAS optical observations
  9. GRB 220521A: Enhanced Swift-XRT position
  10. GRB 220522A: Fermi GBM Final Real-time Localization
  11. GRB 220521A: NOT spectroscopic redshift
  12. GRB 220521A: NOT optical afterglow detection
  13. GRB 220521A: Prompt enhanced Swift-XRT position
  14. GRB 220521A: Swift detection of a burst
  15. GRB 220521A: Fermi GBM Final Real-time Localization
  16. Swift GRB220521.97: Global MASTER-Net observations report
  17. Konus-Wind detection of GRB 220519A
  18. IPN triangulation of GRB 220519A
  19. Swift BAT Trigger 1107209 is not an astrophysical event
  20. GRB 220514A: AstroSat CZTI detection
  21. GRB 220518A: Swift-BAT refined analysis
  22. Swift GRB220519.84: Global MASTER-Net observations report
  23. GRB 220518A: Swift-XRT refined Analysis
  24. Fermi GRB 220518B: Global MASTER-Net observations report
  25. Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
  26. GRB 220518B: Fermi GBM Final Real-time Localization
  27. GRB 220518A: Swift/UVOT Detection
  28. GRB 220518A: Enhanced Swift-XRT position
  29. Swift GRB 220518A: Global MASTER-Net observations report
  30. GRB 220518A: Swift detection of a burst
  31. GRB 220514A: MITSuME Akeno optical observation
  32. GRB 220514A: GRANDMA Optical Afterglow Observations
  33. Konus-Wind detection of GRB 220506A
  34. Konus-Wind detection of GRB 220514B
  35. Fermi trigger No 674397342: Global MASTER-Net observations report
  36. GRB 220514A: Fermi GBM observation
  37. GRB 220514B: Swift-XRT observations
  38. GRB 220511A: Swift-XRT afterglow detection
  39. GRB 220514A: KAIT Optical Afterglow Confirmation
  40. Fermi-LAT Gamma-ray Observations of IceCube-220513A
  41. IceCube-220513A: Upper limits from a search for additional neutrino events in IceCube
  42. GRB 220514B: Tiled Swift observations
  43. [SUBJECT]: IceCube-220513A: No significant detection in HAWC
  44. GRB 220514B: MAXI/GSC detection
  45. MAXI GRB220514.98: Global MASTER-Net observations report
  46. GRB 220514A: MeerLICHT optical afterglow candidate
  47. Integral GRB220514.52: Global MASTER-Net observations report
  48. Fermi GRB 220514A: Global MASTER-Net observations report
  49. GRB 220514A: a long GRB detected by INTEGRAL
  50. IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
  51. GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
  52. GRB 220514A: Fermi GBM Final Real-time Localization
  53. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  54. IceCube Alert 220513.97: Global MASTER-Net observations report
  55. Fermi GRB 220513A: Global MASTER-Net observations report
  56. GRB 220513A: Fermi GBM Final Real-time Localization
  57. Konus-Wind detection of GRB 220511A
  58. GRB 220427A: MeerLICHT afterglow observations
  59. IceCube-220509A: No significant detection in HAWC
  60. GRB 220511A: Fermi GBM observation
  61. GRB 220511A: Swift-XRT observations
  62. GRB 220511A: AstroSat CZTI detection
  63. GRB 220511A: BOOTES-2/TELMA optical upper limit
  64. Fermi GRB 220512A: Global MASTER-Net observations report
  65. GRB 220512A: Fermi GBM Final Real-time Localization
  66. GRB 220511A: Swift ToO observations
  67. GRB 220511A: Swift/BAT-GUANO arcminute localization
  68. Fermi GRB 220511A: Global MASTER-Net observations report
  69. GRB 220511A: AGILE detection
  70. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  71. GRB 220511A: BALROG localization (Fermi Trigger 673969321/ GRB 220511571)
  72. GRB 220511A: Fermi GBM Final Real-time Localization
  73. GRB 220507A: AstroSat CZTI detection
  74. Fermi-LAT Gamma-ray Observations of IceCube-220509A
  75. Fermi trigger No 673846271: Global MASTER-Net observations report
  76. GRB 220506A: MITSuME Akeno optical upper limits
  77. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  78. GRB 220506A: GIT optical upper limit.
  79. IceCube Alert 220509.76: Global MASTER-Net observations report
  80. GRB 220508A: Fermi GBM Final Real-time Localization
  81. GRB 220507A: Fermi GBM Final Localization
  82. GRB 220506A: BOOTES-5/JGT optical upper limit
  83. Fermi trigger No 673610950: Global MASTER-Net observations report
  84. GRB 220506A: Swift-XRT afterglow detection
  85. GRB 220506A: Tiled Swift observations
  86. IceCube-220405B - ZTF19aavnpjv unrelated
  87. Swift-BAT triggers 1105560-1 are not GRBs
  88. Swift GRB220506.51: Global MASTER-Net observations report
  89. GRB 220506A/MAXI J1558-266: MAXI/GSC detection
  90. MAXI GRB220506.27: Global MASTER-Net observations report
  91. GRB 220430A: Nanshan/NEXT optical upper limit
  92. GRB 220430A: Nanshan/HMT optical upper limit
  93. GRB 220430A: GIT optical upper limits
  94. IPN triangulation of GRB 220423A
  95. GRB 220427A: LCO Optical Observations
  96. IceCube-220501A: Upper limits from a search for additional neutrino events in IceCube
  97. GRB 220501A: Swift-BAT refined analysis
  98. Fermi-LAT Gamma-ray Observations of IceCube-220501A
  99. GRB 220427A: GRANDMA Early Optical Afterglow Detection
  100. GRB 220501A: BOOTES-1 optical upper limit

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