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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"

1461 results found.

  1. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube Alert 260505A: Global MASTER-Net observations report
  3. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  4. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  5. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  6. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  7. IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
  8. IceCube Alert 260425A: Global MASTER-Net observations report
  9. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  10. EP260321a: Upper limits from a neutrino search with IceCube
  11. IceCube-260315A: No Candidate Transients from the Zwicky Transient Facility
  12. IceCube-260315A/AT2026fpm: EP-FXT follow-up observation
  13. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  14. IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
  15. IceCube-260315A: COLIBRÍ optical observations
  16. IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
  17. IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube Alert 260315A: Global MASTER-Net observations report
  19. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  20. IceCube cascade alert 142200_1517143 retraction
  21. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube Alert 260217A: Global MASTER-Net observations report
  23. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  24. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  25. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  26. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  27. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  28. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  29. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  30. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  31. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  32. IceCube Alert 260115.73: Global MASTER-Net observations report
  33. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  35. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  36. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  38. IceCube Alert 260111A: Global MASTER-Net observations report
  39. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  40. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  41. IceCube Alert 251225.84: Global MASTER-Net observations report
  42. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  43. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  44. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  45. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  46. IceCube-251218A: COLIBRÍ optical upper limits
  47. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  48. IceCube Alert 251218.85: Global MASTER-Net observations report
  49. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  50. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  51. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-251210A: DDOTI Optical Upper Limit
  53. IceCube Alert 251210.46: Global MASTER-Net observations report
  54. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  55. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  56. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  57. IceCube Alert 251130.75: Global MASTER-Net observations report
  58. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  60. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  61. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  62. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  63. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  64. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  65. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  66. IceCube-251025A: DDOTI Optical Upper Limit
  67. IceCube Alert 251025.57: Global MASTER-Net observations report
  68. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  69. Fermi-LAT gamma-ray observations of IceCube-251018A
  70. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-251018A: DDOTI Optical Upper Limit
  72. IceCube-251018A: Global MASTER-Net observations report
  73. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  75. Upper limits from a search for additional neutrino events in IceCube
  76. IceCube Alert 251014.77: Global MASTER-Net observations report
  77. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  78. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  79. IceCube alert 141456_888784 retraction
  80. IceCube Alert 251008A: Global MASTER-Net observations report
  81. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  82. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  83. IceCube Alert 250926.52: Global MASTER-Net observations report
  84. IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
  85. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  86. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  87. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  88. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  89. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  90. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  91. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  92. IceCube Alert 250905.84: Global MASTER-Net observations report
  93. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  94. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  95. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  96. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  97. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube Alert 250831.75: Global MASTER-Net observations report
  99. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  100. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube

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