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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 220701A: Swift/UVOT Upper Limits
  2. GRB 220701A: Lowell Discovery Telescope Optical Observations
  3. GRB 220701A: Enhanced Swift-XRT position
  4. GRB 200701A: KAIT Optical Upper Limit
  5. GRB 220701A: Swift detection of a burst
  6. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  7. GRB 220627A, GROND observations
  8. GRB 220624A: AGILE/GRID refined analysis
  9. GRB 220627A: Swift/UVOT Upper Limits
  10. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  11. IceCube-220629A: No significant detection in HAWC
  12. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  13. IceCube-220627A: No significant detection in HAWC
  14. IceCube Alert 220629.99: Global MASTER-Net observations report
  15. GRB 220627A: Swift-XRT afterglow detection
  16. Konus-Wind detection of GRB 220627A
  17. Trigger 1113743: Swift detection of MAXI J0655-013
  18. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  19. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  20. GRB 220627A: VLT MUSE redshift
  21. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  22. GRB 220627A: MeerLICHT candidate optical afterglow
  23. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  24. GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
  25. Konus-Wind detection of GRB 220624A
  26. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  27. GRB 220627A: Swift ToO observations
  28. GRB 220627A: Fermi-LAT detection
  29. Fermi trigger No 678058621: Global MASTER-Net observations report
  30. GRB 220627A: MeerLICHT detection of two afterglow candidates
  31. Fermi GRB 220627A: Global MASTER-Net observations report
  32. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  33. GRB 220627A: Fermi GBM Final Real-time Localization
  34. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  35. IceCube Alert 220627.74: Global MASTER-Net observations report
  36. IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-220624A: No significant detection in HAWC
  38. GRB 220623A: GIT optical upper limits.
  39. GRB 220624A: CALET Gamma-Ray Burst Monitor detection
  40. GRB 220623A: T193-OHP optical upper limit
  41. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  42. GRB 220624A: Fermi GBM Detection
  43. Fermi GRB 220623B: Global MASTER-Net observations report
  44. Fermi GRB 220624A: Global MASTER-Net observations report
  45. IceCube Alert 220624.68: Global MASTER-Net observations report
  46. IPN triangulation of GRB 220624A
  47. GRB 220623A: Swift-BAT refined analysis
  48. GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
  49. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  50. GRB 220624A: AGILE/GRID analysis
  51. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  52. GRB 220624A: AGILE detection
  53. Konus-Wind detection of GRB 220623A
  54. GRB 220624B: Fermi GBM Final Real-time Localization
  55. GRB 220624A: Fermi GBM Final Real-time Localization
  56. GRB 220623A: AbAO optical upper limit
  57. GRB 220623A: Swift-XRT refined Analysis
  58. GRB 220623A: NOT optical observations
  59. GRB 220623A: Swift/UVOT Upper Limits
  60. GRB 220623A: BOOTES-5/JGT optical afterglow detection
  61. Konus-Wind detection of GRB 220609B
  62. GRB 220623B: Fermi GBM Final Real-time Localization
  63. GRB 220623A: Enhanced Swift-XRT position
  64. GRB 220623A: AGILE detection
  65. GRB 220623A: AstroSat CZTI detection
  66. GRB 220623A: iTelescope optical upper limit
  67. GRB 220623A: Swift-XRT observations
  68. GRB 220623A: Swift detection of a burst
  69. Fermi trigger No 677597318: Global MASTER-Net observations report
  70. GRB 220618A: Fermi GBM detection
  71. Swift Detection of MAXI J0655-013
  72. GRB 220618A: Swift-BAT refined analysis
  73. GRB 220618A: iTelescope T-19 upper limit
  74. Konus-Wind detection of GRB 220617A
  75. Fermi trigger No 677377371: Global MASTER-Net observations report
  76. Fermi GRB 220620B: Global MASTER-Net observations report
  77. Fermi GRB 220620A: Global MASTER-Net observations report
  78. GRB 220620B: Fermi GBM Final Real-time Localization
  79. Integral GRB220619.53: Global MASTER-Net observations report
  80. GRB 220619A: AstroSat CZTI detection
  81. Swift GRB220620.02: Global MASTER-Net observations report
  82. GRB 220620A: Fermi GBM Final Real-time Localization
  83. GRB 220611A: Continued Gemini Infrared Observations
  84. GRB 220617A: TNG optical observations
  85. Fermi trigger No 677307509: Global MASTER-Net observations report
  86. Fermi trigger No 677236224: Global MASTER-Net observations report
  87. GRB 220617A: Fermi GBM observation
  88. Swift Trigger 1110865 is probably not an astrophysical event
  89. GRB 220611A optical counterpart
  90. GRB 220618A: Swift-XRT refined Analysis
  91. IPN triangulation of GRB 220617A (short)
  92. GRB 220618A: BOOTES-5/JGT early optical upper limit
  93. GRB 220618A: Swift/UVOT Upper Limits
  94. GRB220611A: Gemini Optical Afterglow Confirmation
  95. GRB 220618A: Enhanced Swift-XRT position
  96. GRB 220617A: Swift-XRT observations
  97. GRB 220618A: Swift detection of a burst
  98. Swift GRB220618.38: Global MASTER-Net observations report
  99. GRB 220617A: Fermi-LAT detection
  100. GRB 220617B: Swift ToO observations

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