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

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