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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"

1511 results found.

  1. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  2. IceCube Alert 260825A: Global MASTER-Net observations report
  3. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  5. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  6. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  7. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  8. IceCube Alert 260821A: Global MASTER-Net observations report
  9. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  10. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  12. IceCube Alert 260807A: Global MASTER-Net observations report
  13. IceCube-260805A: One candidate from the Zwicky Transient Facility
  14. IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
  15. GRB 260708A: cubesat Avion detection
  16. IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
  17. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  19. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  20. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  21. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  22. IceCube Alert 260722A: Global MASTER-Net observations report
  23. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  24. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  25. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  26. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  28. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  29. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  30. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  31. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  32. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  33. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  34. IceCube-260708A: One candidate from the Zwicky Transient Facility
  35. IceCube Alert 260709A: Global MASTER-Net observations report
  36. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  37. IceCube-260704A: No candidates from the Zwicky Transient Facility
  38. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  39. IceCube260704A: OHP/T193 optical observations
  40. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  41. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  42. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  43. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  44. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  45. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  46. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  47. IceCube-260610A: No candidates from the Zwicky Transient Facility
  48. IceCube-260610A: EP-FXT follow-up observation
  49. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  51. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube Alert 260505A: Global MASTER-Net observations report
  53. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  54. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  56. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  57. IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
  58. IceCube Alert 260425A: Global MASTER-Net observations report
  59. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  60. EP260321a: Upper limits from a neutrino search with IceCube
  61. IceCube-260315A: No Candidate Transients from the Zwicky Transient Facility
  62. IceCube-260315A/AT2026fpm: EP-FXT follow-up observation
  63. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  64. IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
  65. IceCube-260315A: COLIBRÍ optical observations
  66. IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
  67. IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
  68. IceCube Alert 260315A: Global MASTER-Net observations report
  69. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  70. IceCube cascade alert 142200_1517143 retraction
  71. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  72. IceCube Alert 260217A: Global MASTER-Net observations report
  73. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  74. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  75. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  76. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  77. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  78. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  79. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  80. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  81. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  82. IceCube Alert 260115.73: Global MASTER-Net observations report
  83. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  84. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  85. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  86. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  87. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  88. IceCube Alert 260111A: Global MASTER-Net observations report
  89. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  90. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  91. IceCube Alert 251225.84: Global MASTER-Net observations report
  92. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  93. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  94. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  95. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  96. IceCube-251218A: COLIBRÍ optical upper limits
  97. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  98. IceCube Alert 251218.85: Global MASTER-Net observations report
  99. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  100. Fermi-LAT Gamma-ray Observations of IceCube-251210A

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