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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"

1517 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  2. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  3. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  5. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  6. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  8. IceCube Alert 260825A: Global MASTER-Net observations report
  9. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  11. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  12. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  13. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  14. IceCube Alert 260821A: Global MASTER-Net observations report
  15. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  17. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  18. IceCube Alert 260807A: Global MASTER-Net observations report
  19. IceCube-260805A: One candidate from the Zwicky Transient Facility
  20. IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
  21. GRB 260708A: cubesat Avion detection
  22. IceCube-260805A - IceCube observation of a high-energy neutrino candidate track-like event
  23. IceCube-Cascade 260801A: Upper limits from a search for additional neutrino events in IceCube
  24. Fermi-LAT Gamma-ray Observations of IceCube-260722A
  25. IceCube-260722A: Classification of ZTF26abjbxfs/SN 2026vts as a Type Ia Supernova
  26. IceCube-260722A: Upper limits from a search for additional neutrino events in IceCube
  27. IceCube-260722A: One candidate from the Zwicky Transient Facility (ZTF)
  28. IceCube Alert 260722A: Global MASTER-Net observations report
  29. IceCube-260722A - IceCube observation of a high-energy neutrino candidate track-like event
  30. IceCube-260708A: Follow-up studies of cosmic-ray origin of high-energy neutrino alert
  31. IceCube-260712A: No candidates with the Zwicky Transient Facility (ZTF)
  32. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  33. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  34. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  35. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  36. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  37. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  38. IceCube-260712A - IceCube observation of a high-energy neutrino candidate track-like event
  39. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  40. IceCube-260708A: One candidate from the Zwicky Transient Facility
  41. IceCube Alert 260709A: Global MASTER-Net observations report
  42. IceCube-260708A - IceCube observation of a high-energy neutrino candidate track-like event
  43. IceCube-260704A: No candidates from the Zwicky Transient Facility
  44. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  45. IceCube260704A: OHP/T193 optical observations
  46. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  47. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  48. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  49. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  50. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  51. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  52. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  53. IceCube-260610A: No candidates from the Zwicky Transient Facility
  54. IceCube-260610A: EP-FXT follow-up observation
  55. IceCube-260610A - IceCube observation of a high-energy neutrino candidate track-like event
  56. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  57. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube Alert 260505A: Global MASTER-Net observations report
  59. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  60. IceCube-260504A - IceCube observation of a high-energy neutrino candidate track-like event
  61. IceCube-260425A: Upper limits from a search for additional neutrino events in IceCube
  62. Fermi-LAT Gamma-ray Observations of IceCube-260425A
  63. IceCube-260425A - IceCube observation of a high-energy neutrino candidate track-like event
  64. IceCube Alert 260425A: Global MASTER-Net observations report
  65. IceCube-Cascade 260418A: Upper limits from a search for additional neutrino events in IceCube
  66. EP260321a: Upper limits from a neutrino search with IceCube
  67. IceCube-260315A: No Candidate Transients from the Zwicky Transient Facility
  68. IceCube-260315A/AT2026fpm: EP-FXT follow-up observation
  69. Fermi-LAT Gamma-ray Observations of IceCube-260315A
  70. IceCube-260315A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-260315A: COLIBRÍ optical observations
  72. IceCube Alert-260315A/AT2026fpm Automatic MASTER optical blue counterpart candidate
  73. IceCube-260315A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube Alert 260315A: Global MASTER-Net observations report
  75. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  76. IceCube cascade alert 142200_1517143 retraction
  77. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube Alert 260217A: Global MASTER-Net observations report
  79. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  80. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  81. IceCube-260125A: No Candidate Transients from the Zwicky Transient Facility
  82. IceCube-260125A: Upper limits from a search for additional neutrino events in IceCube
  83. Fermi-LAT Gamma-ray Observations of IceCube-260125A
  84. IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
  85. IceCube-260115A: No Candidate Transients from the Zwicky Transient Facility
  86. Fermi-LAT Gamma-ray Observations of IceCube-260115A
  87. IceCube-260115A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube Alert 260115.73: Global MASTER-Net observations report
  89. IceCube-260115A - IceCube observation of a high-energy neutrino candidate track-like event
  90. IceCube: GCN Notices for high-energy track alerts now streamed via Kafka
  91. Fermi-LAT Gamma-ray Observations of IceCube-260111A
  92. IceCube-260111A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-260111A - IceCube observation of a high-energy neutrino candidate track-like event
  94. IceCube Alert 260111A: Global MASTER-Net observations report
  95. Fermi-LAT Gamma-ray Observations of IceCube-251225A
  96. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  97. IceCube Alert 251225.84: Global MASTER-Net observations report
  98. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  99. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  100. Fermi-LAT Gamma-ray Observations of IceCube-251218A

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