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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 220708A: Swift/UVOT Upper Limits
  2. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  3. GRB 220708A: Swift-XRT refined Analysis
  4. GRB 220706A: Swift/UVOT Upper Limits
  5. GRB 220708B: Swift-XRT afterglow detection
  6. GRB 220708A: BOOTES-5/JGT early optical upper limit
  7. GRB 220706A: Swift-BAT refined analysis
  8. GRB 220708A: Enhanced Swift-XRT position
  9. GRB 220708B: Swift ToO observations
  10. GRB 220708B: Swift/BAT-GUANO arcminute localization
  11. GRB 220708A: Swift-XRT observations
  12. GRB 220708A: Swift detection of a burst
  13. GRB 220706A: LCO Optical Upper Limits
  14. GRB 220627A: ATCA detection of radio counterpart
  15. GRB 220706A: Swift-XRT refined Analysis
  16. GRB 220706A, GROND observations
  17. GRB 220706A: Optical observations from NOT
  18. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  19. GRB 220702B: AstroSat CZTI detection
  20. GRB 220706A: Nanshan/NEXT optical upper limits
  21. MAXI GRB220706.73: Global MASTER-Net observations report
  22. GRB 220706A: Enhanced Swift-XRT position
  23. Swift GRB 220706A: Global MASTER-Net observations report
  24. GRB 220706A: Zadko observatory - Gingin optical observations
  25. GRB 220706A: Prompt enhanced Swift-XRT position
  26. GRB 220706A: Swift detection of a burst
  27. GRB 220701A: Swift-BAT refined analysis
  28. GRB220408A: VIRT Optical Upper Limit
  29. GRB220412A: VIRT Optical Upper Limit
  30. GRB220701A: VIRT Optical Upper Limit
  31. GRB 220702B: Fermi GBM Final Localization
  32. GRB 220702A: Fermi GBM Final Localization
  33. GRB 220705A: Fermi GBM Final Localization
  34. Fermi trigger No 678635286: Global MASTER-Net observations report
  35. GRB 220701A: MITSuME Akeno optical upper limits
  36. Alert from the HAWC Burst Monitor HAWC-220702A
  37. GRB 220701A: COATLI Optical Upper Limit
  38. GRB 220701A: AbAO optical upper limit
  39. GRB 220627A: AstroSat CZTI detection
  40. GRB 220701A: Keck/LRIS Optical Upper Limit
  41. GRB 220701A: Swift-XRT refined Analysis
  42. GRB 220701A: LCO Optical Upper Limits
  43. IceCube-220629A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 220701A: BOOTES-5/JGT early optical upper limit
  45. GRB 220701A: Swift/UVOT Upper Limits
  46. GRB 220701A: Lowell Discovery Telescope Optical Observations
  47. GRB 220701A: Enhanced Swift-XRT position
  48. GRB 200701A: KAIT Optical Upper Limit
  49. GRB 220701A: Swift detection of a burst
  50. Fermi-LAT Gamma-ray Observations of IceCube-220629A
  51. GRB 220627A, GROND observations
  52. GRB 220624A: AGILE/GRID refined analysis
  53. GRB 220627A: Swift/UVOT Upper Limits
  54. Fermi-LAT Gamma-ray Observations of IceCube-220627A
  55. IceCube-220629A: No significant detection in HAWC
  56. IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
  57. IceCube-220627A: No significant detection in HAWC
  58. IceCube Alert 220629.99: Global MASTER-Net observations report
  59. GRB 220627A: Swift-XRT afterglow detection
  60. Konus-Wind detection of GRB 220627A
  61. Trigger 1113743: Swift detection of MAXI J0655-013
  62. IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
  63. IceCube-220627A: Upper limits from a search for additional neutrino events in IceCube
  64. GRB 220627A: VLT MUSE redshift
  65. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  66. GRB 220627A: MeerLICHT candidate optical afterglow
  67. GRB 220627A: Fermi GBM Detection of a possible Lensed or Ultra-long GRB
  68. GRB 220627A: Swift/BAT-GUANO detection outside the coded FOV
  69. Konus-Wind detection of GRB 220624A
  70. Fermi-LAT Gamma-ray Observations of IceCube-220624A and and detection of a new gamma-ray source, Fermi J1458.0+4119
  71. GRB 220627A: Swift ToO observations
  72. GRB 220627A: Fermi-LAT detection
  73. Fermi trigger No 678058621: Global MASTER-Net observations report
  74. GRB 220627A: MeerLICHT detection of two afterglow candidates
  75. Fermi GRB 220627A: Global MASTER-Net observations report
  76. IceCube-Cascade 220625A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 220627A: Fermi GBM Final Real-time Localization
  78. IceCube-220627A - IceCube observation of a high-energy neutrino candidate track-like event
  79. IceCube Alert 220627.74: Global MASTER-Net observations report
  80. IceCube-220624A: Upper limits from a search for additional neutrino events in IceCube
  81. IceCube-220624A: No significant detection in HAWC
  82. GRB 220623A: GIT optical upper limits.
  83. GRB 220624A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 220623A: T193-OHP optical upper limit
  85. IceCube-220624A: No Candidate Counterparts from the Zwicky Transient Facility
  86. GRB 220624A: Fermi GBM Detection
  87. Fermi GRB 220623B: Global MASTER-Net observations report
  88. Fermi GRB 220624A: Global MASTER-Net observations report
  89. IceCube Alert 220624.68: Global MASTER-Net observations report
  90. IPN triangulation of GRB 220624A
  91. GRB 220623A: Swift-BAT refined analysis
  92. GRB 220624A: Swift/BAT-GUANO detection outside the coded FOV
  93. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  94. GRB 220624A: AGILE/GRID analysis
  95. IceCube-220624A - IceCube observation of a high-energy neutrino candidate track-like event
  96. GRB 220624A: AGILE detection
  97. Konus-Wind detection of GRB 220623A
  98. GRB 220624B: Fermi GBM Final Real-time Localization
  99. GRB 220624A: Fermi GBM Final Real-time Localization
  100. GRB 220623A: AbAO optical upper limit

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