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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: ISON-Castelgrande observatory optical observations
  2. IceCube-220524A - IceCube observation of a high-energy neutrino candidate track-like event
  3. GRB 220521A: MITSuME Akeno optical upper limits
  4. Fermi GRB 220523B: Global MASTER-Net observations report
  5. GRB 220521A: Gemini Observations
  6. GRB 220523B: Fermi GBM detection
  7. GRB 220521A: MMT Afterglow Imaging
  8. GRB 220521A: REM optical/NIR upper limits
  9. GRB 220514A: Swift/BAT-GUANO detection outside the coded FOV
  10. VLA observations of GW170817 at ~4.8 years after the merger
  11. Fermi GRB 220523A: Global MASTER-Net observations report
  12. GRB 220523A: Fermi GBM Final Real-time Localization
  13. GRB 220521A: LCO Optical Detection
  14. GRB 220521A: Swift-BAT refined analysis
  15. GRB 220521A: Fermi GBM detection
  16. GRB 220521A: Sintesz-Newton/CrAO optical upper limit
  17. GRB 220521A: RATIR Optical and NIR Observations
  18. GRB 220521A: Swift-XRT refined Analysis
  19. GRB 220521A: Swift/UVOT Upper Limits
  20. Fermi GRB 220522A: Global MASTER-Net observations report
  21. Fermi trigger No 674868783: Global MASTER-Net observations report
  22. GRB 220521A: SAO RAS optical observations
  23. GRB 220521A: Enhanced Swift-XRT position
  24. GRB 220522A: Fermi GBM Final Real-time Localization
  25. GRB 220521A: NOT spectroscopic redshift
  26. GRB 220521A: NOT optical afterglow detection
  27. GRB 220521A: Prompt enhanced Swift-XRT position
  28. GRB 220521A: Swift detection of a burst
  29. GRB 220521A: Fermi GBM Final Real-time Localization
  30. Swift GRB220521.97: Global MASTER-Net observations report
  31. Konus-Wind detection of GRB 220519A
  32. IPN triangulation of GRB 220519A
  33. Swift BAT Trigger 1107209 is not an astrophysical event
  34. GRB 220514A: AstroSat CZTI detection
  35. GRB 220518A: Swift-BAT refined analysis
  36. Swift GRB220519.84: Global MASTER-Net observations report
  37. GRB 220518A: Swift-XRT refined Analysis
  38. Fermi GRB 220518B: Global MASTER-Net observations report
  39. Continued Chandra monitoring of GW170817 at ~4.8 yr post-merger
  40. GRB 220518B: Fermi GBM Final Real-time Localization
  41. GRB 220518A: Swift/UVOT Detection
  42. GRB 220518A: Enhanced Swift-XRT position
  43. Swift GRB 220518A: Global MASTER-Net observations report
  44. GRB 220518A: Swift detection of a burst
  45. GRB 220514A: MITSuME Akeno optical observation
  46. GRB 220514A: GRANDMA Optical Afterglow Observations
  47. Konus-Wind detection of GRB 220506A
  48. Konus-Wind detection of GRB 220514B
  49. Fermi trigger No 674397342: Global MASTER-Net observations report
  50. GRB 220514A: Fermi GBM observation
  51. GRB 220514B: Swift-XRT observations
  52. GRB 220511A: Swift-XRT afterglow detection
  53. GRB 220514A: KAIT Optical Afterglow Confirmation
  54. Fermi-LAT Gamma-ray Observations of IceCube-220513A
  55. IceCube-220513A: Upper limits from a search for additional neutrino events in IceCube
  56. GRB 220514B: Tiled Swift observations
  57. IceCube-220513A: No significant detection in HAWC
  58. GRB 220514B: MAXI/GSC detection
  59. MAXI GRB220514.98: Global MASTER-Net observations report
  60. GRB 220514A: MeerLICHT optical afterglow candidate
  61. Integral GRB220514.52: Global MASTER-Net observations report
  62. Fermi GRB 220514A: Global MASTER-Net observations report
  63. GRB 220514A: a long GRB detected by INTEGRAL
  64. IceCube-220513A: No Candidate Counterparts from the Zwicky Transient Facility
  65. GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
  66. GRB 220514A: Fermi GBM Final Real-time Localization
  67. IceCube-220513A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube Alert 220513.97: Global MASTER-Net observations report
  69. Fermi GRB 220513A: Global MASTER-Net observations report
  70. GRB 220513A: Fermi GBM Final Real-time Localization
  71. Konus-Wind detection of GRB 220511A
  72. GRB 220427A: MeerLICHT afterglow observations
  73. IceCube-220509A: No significant detection in HAWC
  74. GRB 220511A: Fermi GBM observation
  75. GRB 220511A: Swift-XRT observations
  76. GRB 220511A: AstroSat CZTI detection
  77. GRB 220511A: BOOTES-2/TELMA optical upper limit
  78. Fermi GRB 220512A: Global MASTER-Net observations report
  79. GRB 220512A: Fermi GBM Final Real-time Localization
  80. GRB 220511A: Swift ToO observations
  81. GRB 220511A: Swift/BAT-GUANO arcminute localization
  82. Fermi GRB 220511A: Global MASTER-Net observations report
  83. GRB 220511A: AGILE detection
  84. IceCube-220509A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 220511A: BALROG localization (Fermi Trigger 673969321/ GRB 220511571)
  86. GRB 220511A: Fermi GBM Final Real-time Localization
  87. GRB 220507A: AstroSat CZTI detection
  88. Fermi-LAT Gamma-ray Observations of IceCube-220509A
  89. Fermi trigger No 673846271: Global MASTER-Net observations report
  90. GRB 220506A: MITSuME Akeno optical upper limits
  91. IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event
  92. GRB 220506A: GIT optical upper limit.
  93. IceCube Alert 220509.76: Global MASTER-Net observations report
  94. GRB 220508A: Fermi GBM Final Real-time Localization
  95. GRB 220507A: Fermi GBM Final Localization
  96. GRB 220506A: BOOTES-5/JGT optical upper limit
  97. Fermi trigger No 673610950: Global MASTER-Net observations report
  98. GRB 220506A: Swift-XRT afterglow detection
  99. GRB 220506A: Tiled Swift observations
  100. IceCube-220405B - ZTF19aavnpjv unrelated

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