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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. Swift GRB200816.17: Global MASTER-Net observations report
  2. Fermi trigger No 619270776: Global MASTER-Net observations report
  3. Swift trigger 989458 is likely not an astrophysical source
  4. HAWC alert 200815.26: MASTER optical observations
  5. Alert from the HAWC Burst Monitor HAWC-200814A
  6. IceCube200806A: No significant detection in HAWC
  7. GRB 200811A: Fermi GBM Final Real-time Localization
  8. GRB 200811A: BALROG localization (Fermi Trigger 618851447 / GRB 200811632)
  9. GRB 200809B: Fermi GBM detection
  10. Fermi GRB 200809B: Global MASTER-Net observations report
  11. GRB 200809B: BOOTES-3/YA optical upper limit
  12. GRB 200809B: Swift-XRT afterglow detection
  13. GRB 200809B: MAXI/GSC detection
  14. GRB 200809B: Swift ToO observations
  15. GRB 200809B: AstroSat CZTI detection
  16. GRB 200809B: Swift/BAT-GUANO detection and arcminute localization
  17. GRB 200809B: Fermi GBM Final Real-time Localization
  18. GRB 200808A: AGILE detection
  19. GRB 200806A: CALET Gamma-Ray Burst Monitor detection
  20. Fermi trigger No 618642276: Global MASTER-Net observations report
  21. GRB 200809A: Fermi GBM Final Real-time Localization
  22. Fermi GRB 200808A: Global MASTER-Net observations report
  23. GRB 200808A: Fermi GBM Final Real-time Localization
  24. GRB 200806A: Nanshan/NEXT optical upper limit
  25. IPN triangulation of GRB 200805A (short)
  26. GRB 200806A: CAHA optical afterglow confirmation
  27. GRB 200803A: Chilescope optical upper limit
  28. IceCube-200806A: Upper limits from a search for additional neutrino events in IceCube
  29. GRB 200806A: VIRT optical observations
  30. GRB 200806A: Swift-BAT refined analysis
  31. GRB 200806A: Swift/UVOT Possible Detection
  32. GRB 200806A: Swift-XRT refined Analysis
  33. Fermi-LAT Gamma-ray Observations of IceCube-200806A
  34. CGBM-SPI-ACS triangulation of short GRB 200805A
  35. GRB 200806A: AbAO optical upper limit
  36. GRB 200805A: CALET Gamma-Ray Burst Monitor detection of a short burst
  37. GRB 200806A: AstroSat CZTI detection
  38. GRB 200806A: MITSuME Akeno optical upper limits
  39. GRB 200806A: Enhanced Swift-XRT position
  40. IceCube-200806A: Upper limits from Fermi-GBM Observations
  41. Swift GRB 200806A: Global MASTER-Net observations report
  42. GRB 200806A: Swift detection of a burst
  43. IceCube-200806A: IceCube observation of a high-energy neutrino candidate event
  44. IceCube Alert 200806.58: Global MASTER-Net observations report
  45. GRB 200803B: MASTER possibly OT discovery
  46. GRB 200803A: AstroSat CZTI detection
  47. GRB 200803A: Fermi GBM detection
  48. GRB 200803A: Swift-XRT afterglow detection
  49. Fermi GRB 200803B: Global MASTER-Net observations report
  50. GRB 200803A: Fermi-LAT detection
  51. GRB 200803A: MASTER optical counterpart discovery
  52. GRB 200803B: Fermi GBM Final Real-time Localization
  53. GRB 200803A: Tiled Swift observations
  54. LAT GRB200803.15: Global MASTER-Net observations report
  55. Fermi GRB 200803A: Global MASTER-Net observations report
  56. GRB 200801B: AstroSat CZTI detection
  57. GRB 200803A: Fermi GBM Final Real-time Localization
  58. Fermi GRB 200801B: Global MASTER-Net observations report
  59. Fermi GRB 200802A: Global MASTER-Net observations report
  60. AX J1846.4-0258: Swift-BAT refined analysis
  61. Konus-Wind detection of GRB 200729A
  62. GRB 200802A: BALROG localization (Fermi Trigger 618061611 / GRB 200802491)
  63. GRB 200802A: Fermi GBM Final Real-time Localization
  64. GRB 200801C: BOOTES-1 and BOOTES-2 optical limits
  65. Fermi GRB 200801A: Global MASTER-Net observations report
  66. Swift Detection of an SGR-like flare from AX J1846.4-0258
  67. Swift GRB200801.84: Global MASTER-Net observations report
  68. GRB 200801B: BALROG localization (Fermi Trigger 617988951 / GRB 200801650)
  69. GRB 200801B: Fermi GBM Final Real-time Localization
  70. GRB 200801A: Fermi GBM Final Real-time Localization
  71. GRB 200729A: RT-22 observations at 36.8 GHz
  72. GRB 200729A: VLA Observations
  73. GRB 200729A: Nanshan/NEXT optical upper limit
  74. GRB 200729A: Swift-BAT refined analysis
  75. GRB 200729A: further analysis of the NOT data
  76. GRB 200729A: Swift/UVOT Upper Limits
  77. GRB 200729A: Swift-XRT refined Analysis
  78. GRB 200729A: HST imaging
  79. Fermi-GBM Sub-Threshold candidate for GRB 200729A
  80. GRB 200729A: IceCube neutrino search
  81. GRB 200729A: Pan-STARRS pre-explosion source detection
  82. GRB 200729A: Spitzer archival source detection
  83. GRB 200729A: TNG NIR upper limits
  84. GRB 200729A: NOT optical upper limits
  85. GRB 200729A: Enhanced Swift-XRT position
  86. GRB200729A: BOOTES-1 optical upper limit
  87. Swift GRB 200729A: Global MASTER-Net observations report
  88. GRB 200729A: Swift detection of a burst
  89. IceCube Alert 200728.35: Global MASTER-Net observations report
  90. IceCube GCN Notice 134327_10548129 retraction
  91. Baksan Neutrino Observatory Alert 200726.66: Global MASTER-Net observations report
  92. GRB 200723A: ATLAS observations of GOTO candidate AT2020qer
  93. GRB 200723A: Swift ToO observations
  94. GRB 200723A: GOTO candidate afterglow and host galaxy
  95. GRB 200724A: Fermi GBM Final Real-time Localization
  96. Fermi GRB 200723A: Global MASTER-Net observations report
  97. GRB 200723A: BALROG localization (Fermi Trigger 617214929 / GRB 200723691)
  98. GRB 200723A: Fermi GBM Final Real-time Localization
  99. GRB 200716C: Kitab optical observations
  100. GRB 200722A: BALROG localization (Fermi Trigger 617076900 / GRB 200722094)

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