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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. Fermi-LAT Gamma-ray Observations of IceCube-220421A
  2. GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
  3. Fermi trigger No 672221879: Global MASTER-Net observations report
  4. Fermi GBM trigger 672128054/220420260 is not a GRB
  5. IceCube-220421A - IceCube observation of a high-energy neutrino candidate track-like event
  6. GRB 220418B: Swift-XRT observations
  7. IceCube Alert 220421.22: Global MASTER-Net observations report
  8. GRB 220418B Fermi GBM observation
  9. Fermi trigger No 672093919: Global MASTER-Net observations report
  10. “GRB 220420A” is not a GRB
  11. GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
  12. GRB 220403C: Further Swift-XRT observations
  13. GRB 220418B: Swift ToO observations
  14. GRB 220417A: Fermi GBM detection
  15. GRB 220418B: Swift/BAT-GUANO refined location of a short burst
  16. IPN triangulation of GRB 220411A
  17. GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
  18. GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
  19. GRB 220412B: Swift/UVOT Upper Limits
  20. Fermi GRB 220418A: Global MASTER-Net observations report
  21. GRB 220418B: Fermi GBM Final Real-time Localization
  22. GRB 220418A: Fermi GBM Final Real-time Localization
  23. Fermi GRB 220417A: Global MASTER-Net observations report
  24. GRB 220417A: Fermi GBM Final Real-time Localization
  25. Fermi trigger No 671729344: Global MASTER-Net observations report
  26. GRB 220412B: Swift-BAT refined analysis
  27. Konus-Wind detection of GRB 220412B
  28. GRB 220412B: Fermi GBM observation
  29. Konus-Wind detection of GRB 220403C
  30. GRB 220408B: Fermi GBM observation
  31. Konus-Wind detection of GRB 220408B
  32. GRB 220412B: TNG optical observations
  33. GRB 220412A: GRANDMA observations
  34. GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve
  35. GRB 220412A: BOOTES-network optical upper limits
  36. GRB 220412B: BOOTES-1 optical upper limit
  37. GRB 220412A: Swift-BAT refined analysis
  38. GRB 220412A: RATIR Observations of the Fading Afterglow
  39. GRB 220412B: Swift-XRT observations
  40. GRB 220408B: Fermi-LAT detection
  41. IPN triangulation of short/soft GRB 220406A
  42. Swift GRB 220412B: Global MASTER-Net observations report
  43. GRB 220408A: HCT optical upper limit
  44. GRB 220412B: GIT optical upper limit
  45. GRB 220412A: MITSuME Akeno optical upper limits
  46. Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
  47. GRB 220412B: MITSuME Akeno optical upper limits
  48. GRB 220412A: Swift-XRT refined Analysis
  49. GRB 220412A: Enhanced Swift-XRT position
  50. GRB 220412B: Swift detection of a short burst
  51. GRB 220412A: Swift/UVOT Upper Limits
  52. GRB 220408A: GRANDMA observations
  53. GRB 220403B: GRANDMA observations
  54. GRB 220412A: RATIR Afterglow Candidate
  55. GRB 220412A: Swift detection of a burst
  56. Swift GRB220412.28: Global MASTER-Net observations report
  57. GRB 220411A: AstroSat CZTI detection
  58. IPN triangulation of GRB 220408B
  59. IPN triangulation of GRB 220403C
  60. GRB 220403B: Swift/UVOT Detection
  61. GRB 220408A: Lowell Discovery Telescope Optical Observations
  62. GRB 220408A: Swift-BAT refined analysis
  63. Fermi GRB 220411A: Global MASTER-Net observations report
  64. GRB 220411A: BALROG localization (Fermi Trigger 671354405/ GRB 220411306)
  65. GRB 220411A: Fermi GBM Final Real-time Localization
  66. GRB 220408A: RATIR Optical and NIR Observations
  67. GRB 220403B: 1.3m DFOT Optical upper limit
  68. GRB 220408A: 1.3m DFOT Optical upper limit
  69. GRB 220408A: LOAO, DOAO, and, SAO optical upper limit
  70. GRB 220403C: Swift-XRT observations
  71. GRB 220408A: redshift lower limit estimating
  72. GRB 220408A: NOT optical observations and archival detection
  73. GRB 220408B: AstroSat CZTI detection
  74. GRB 220408A: LCO Optical Afterglow Detection
  75. GRB 220408A: Swift-XRT refined Analysis
  76. GRB 220403C: Swift ToO observations
  77. GRB 220408A: BOOTES-5/JGT optical afterglow detection
  78. Fermi GRB 220408B: Global MASTER-Net observations report
  79. GRB 220408A: GIT optical upper limit
  80. GRB 220408A: Fermi GBM observation
  81. GRB 220408A: Swift/UVOT Detection
  82. GRB 220408B: Fermi GBM Final Localization
  83. GRB 220408A: Xinglong-2.16m optical upper limit
  84. GRB 220408A: Enhanced Swift-XRT position
  85. Chandra upper limit at the location of GRB 220408A
  86. GRB 220408A: KAIT Optical Observations
  87. Fermi GRB 220408A: Global MASTER-Net observations report
  88. GRB 220408A: Swift detection of a burst with an optical counterpart, possibly associated with M51
  89. GRB 220408A: Fermi GBM Final Real-time Localization
  90. ZTF22aaajecp/AT2022cmc: continued optical observations (Mondy, SAO RAS, CrAO)
  91. Fermi-LAT Gamma-ray Observations of IceCube-220405B
  92. GRB 220403B: Mondy optical upper limit
  93. IceCube-220405A: No Candidate Counterparts from the Zwicky Transient Facility
  94. IceCube-220405B: No Candidate Counterparts from the Zwicky Transient Facility
  95. GRB 220403B: 1.5m OSN optical observation
  96. IceCube Alert 220405.93: Global MASTER-Net observations report
  97. IceCube-220405A - IceCube observation of a high-energy neutrino candidate track-like event
  98. GRB 220404A: Swift-BAT refined analysis
  99. GRB 220403B: Kitab optical observations
  100. Fermi-LAT Gamma-ray Observations of IceCube-220405A

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