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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"

1508 results found.

  1. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  2. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  3. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  4. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  5. IceCube Alert 260821A: Global MASTER-Net observations report
  6. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  8. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  9. IceCube Alert 260807A: Global MASTER-Net observations report
  10. IceCube-260805A: One candidate from the Zwicky Transient Facility
  11. IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
  12. GRB 260708A: cubesat Avion detection
  13. IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
  14. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  15. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  16. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  17. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  18. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  19. IceCube Alert 260722A: Global MASTER-Net observations report
  20. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  21. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  22. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  23. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  24. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  25. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  26. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  27. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  28. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  29. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  30. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  31. IceCube-260708A: One candidate from the Zwicky Transient Facility
  32. IceCube Alert 260709A: Global MASTER-Net observations report
  33. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube-260704A: No candidates from the Zwicky Transient Facility
  35. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  36. IceCube260704A: OHP/T193 optical observations
  37. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  38. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  39. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  41. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  42. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  43. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  44. IceCube-260610A: No candidates from the Zwicky Transient Facility
  45. IceCube-260610A: EP-FXT follow-up observation
  46. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  47. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  48. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  49. IceCube Alert 260505A: Global MASTER-Net observations report
  50. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  51. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  52. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  53. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  54. IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube Alert 260425A: Global MASTER-Net observations report
  56. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  57. EP260321a: Upper limits from a neutrino search with IceCube
  58. IceCube-260315A: No Candidate Transients from the Zwicky Transient Facility
  59. IceCube-260315A/AT2026fpm: EP-FXT follow-up observation
  60. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  61. IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-260315A: COLIBRÍ optical observations
  63. IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
  64. IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
  65. IceCube Alert 260315A: Global MASTER-Net observations report
  66. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  67. IceCube cascade alert 142200_1517143 retraction
  68. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube Alert 260217A: Global MASTER-Net observations report
  70. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  71. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  72. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  73. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  74. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  75. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  76. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  77. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  78. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  79. IceCube Alert 260115.73: Global MASTER-Net observations report
  80. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  81. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  82. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  83. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  84. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  85. IceCube Alert 260111A: Global MASTER-Net observations report
  86. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  87. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube Alert 251225.84: Global MASTER-Net observations report
  89. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  90. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  91. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  92. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-251218A: COLIBRÍ optical upper limits
  94. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  95. IceCube Alert 251218.85: Global MASTER-Net observations report
  96. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  97. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  98. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  99. IceCube-251210A: DDOTI Optical Upper Limit
  100. IceCube Alert 251210.46: Global MASTER-Net observations report

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