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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. Trigger 1113743: Swift detection of MAXI J0655-013
  2. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  3. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  4. GRB 220627A: VLT MUSE redshift
  5. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  6. GRB 220627A: MeerLICHT candidate optical afterglow
  7. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  8. GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
  9. Konus-Wind detection of GRB 220624A
  10. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  11. GRB 220627A: Swift ToO observations
  12. GRB 220627A: Fermi-LAT detection
  13. Fermi trigger No 678058621: Global MASTER-Net observations report
  14. GRB 220627A: MeerLICHT detection of two afterglow candidates
  15. Fermi GRB 220627A: Global MASTER-Net observations report
  16. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 220627A: Fermi GBM Final Real-time Localization
  18. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  19. IceCube Alert 220627.74: Global MASTER-Net observations report
  20. IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-220624A: No significant detection in HAWC
  22. GRB 220623A: GIT optical upper limits.
  23. GRB 220624A: CALET Gamma-Ray Burst Monitor detection
  24. GRB 220623A: T193-OHP optical upper limit
  25. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  26. GRB 220624A: Fermi GBM Detection
  27. Fermi GRB 220623B: Global MASTER-Net observations report
  28. Fermi GRB 220624A: Global MASTER-Net observations report
  29. IceCube Alert 220624.68: Global MASTER-Net observations report
  30. IPN triangulation of GRB 220624A
  31. GRB 220623A: Swift-BAT refined analysis
  32. GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
  33. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  34. GRB 220624A: AGILE/GRID analysis
  35. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 220624A: AGILE detection
  37. Konus-Wind detection of GRB 220623A
  38. GRB 220624B: Fermi GBM Final Real-time Localization
  39. GRB 220624A: Fermi GBM Final Real-time Localization
  40. GRB 220623A: AbAO optical upper limit
  41. GRB 220623A: Swift-XRT refined Analysis
  42. GRB 220623A: NOT optical observations
  43. GRB 220623A: Swift/UVOT Upper Limits
  44. GRB 220623A: BOOTES-5/JGT optical afterglow detection
  45. Konus-Wind detection of GRB 220609B
  46. GRB 220623B: Fermi GBM Final Real-time Localization
  47. GRB 220623A: Enhanced Swift-XRT position
  48. GRB 220623A: AGILE detection
  49. GRB 220623A: AstroSat CZTI detection
  50. GRB 220623A: iTelescope optical upper limit
  51. GRB 220623A: Swift-XRT observations
  52. GRB 220623A: Swift detection of a burst
  53. Fermi trigger No 677597318: Global MASTER-Net observations report
  54. GRB 220618A: Fermi GBM detection
  55. Swift Detection of MAXI J0655-013
  56. GRB 220618A: Swift-BAT refined analysis
  57. GRB 220618A: iTelescope T-19 upper limit
  58. Konus-Wind detection of GRB 220617A
  59. Fermi trigger No 677377371: Global MASTER-Net observations report
  60. Fermi GRB 220620B: Global MASTER-Net observations report
  61. Fermi GRB 220620A: Global MASTER-Net observations report
  62. GRB 220620B: Fermi GBM Final Real-time Localization
  63. Integral GRB220619.53: Global MASTER-Net observations report
  64. GRB 220619A: AstroSat CZTI detection
  65. Swift GRB220620.02: Global MASTER-Net observations report
  66. GRB 220620A: Fermi GBM Final Real-time Localization
  67. GRB 220611A: Continued Gemini Infrared Observations
  68. GRB 220617A: TNG optical observations
  69. Fermi trigger No 677307509: Global MASTER-Net observations report
  70. Fermi trigger No 677236224: Global MASTER-Net observations report
  71. GRB 220617A: Fermi GBM observation
  72. Swift Trigger 1110865 is probably not an astrophysical event
  73. GRB 220611A optical counterpart
  74. GRB 220618A: Swift-XRT refined Analysis
  75. IPN triangulation of GRB 220617A (short)
  76. GRB 220618A: BOOTES-5/JGT early optical upper limit
  77. GRB 220618A: Swift/UVOT Upper Limits
  78. GRB220611A: Gemini Optical Afterglow Confirmation
  79. GRB 220618A: Enhanced Swift-XRT position
  80. GRB 220617A: Swift-XRT observations
  81. GRB 220618A: Swift detection of a burst
  82. Swift GRB220618.38: Global MASTER-Net observations report
  83. GRB 220617A: Fermi-LAT detection
  84. GRB 220617B: Swift ToO observations
  85. Fermi GRB 220617A: Global MASTER-Net observations report
  86. GRB 220617A: Fermi GBM Final Real-time Localization
  87. GRB 220611A: Gemini Ks counterpart detection
  88. Fermi trigger No 677174940: Global MASTER-Net observations report
  89. Konus-Wind detection of GRB 220613A
  90. IPN triangulation of GRB 220613A
  91. Konus-Wind detection of an intermediate flare from SGR 1935+2154 on June 16
  92. GRB 220611A: Gemini South Infrared Detection
  93. IPN triangulation of GRB 220606C
  94. GRB 220611A: Swift/UVOT Upper Limits
  95. Fermi trigger No 676909037: Global MASTER-Net observations report
  96. GRB 220612A: CALET Gamma-Ray Burst Monitor detection
  97. GRB 220612A: Swift/BAT-GUANO detection
  98. GRB 220611A: Swift-BAT refined analysis
  99. GRB 220608B: Detection by VZLUSAT-2
  100. Swift GRB 220611A: Global MASTER-Net observations report

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