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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"

1520 results found.

  1. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  2. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  3. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  4. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  5. IceCube-251218A: COLIBRÍ optical upper limits
  6. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube Alert 251218.85: Global MASTER-Net observations report
  8. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  9. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  10. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-251210A: DDOTI Optical Upper Limit
  12. IceCube Alert 251210.46: Global MASTER-Net observations report
  13. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  14. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  15. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  16. IceCube Alert 251130.75: Global MASTER-Net observations report
  17. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  18. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  19. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  20. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  21. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  22. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  23. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  24. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  25. IceCube-251025A: DDOTI Optical Upper Limit
  26. IceCube Alert 251025.57: Global MASTER-Net observations report
  27. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  28. Fermi-LAT gamma-ray observations of IceCube-251018A
  29. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  30. IceCube-251018A: DDOTI Optical Upper Limit
  31. IceCube-251018A: Global MASTER-Net observations report
  32. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  33. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  34. Upper limits from a search for additional neutrino events in IceCube
  35. IceCube Alert 251014.77: Global MASTER-Net observations report
  36. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  37. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  38. IceCube alert 141456_888784 retraction
  39. IceCube Alert 251008A: Global MASTER-Net observations report
  40. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  41. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube Alert 250926.52: Global MASTER-Net observations report
  43. IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
  44. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  45. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  46. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  47. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  48. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  49. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  50. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  51. IceCube Alert 250905.84: Global MASTER-Net observations report
  52. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  53. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  54. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  55. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  56. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  57. IceCube Alert 250831.75: Global MASTER-Net observations report
  58. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  60. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  61. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  62. IceCube Alert 250813.14: Global MASTER-Net observations report
  63. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  64. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  65. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  67. IceCube Alert 250804.84: Global MASTER-Net observations report
  68. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  69. IceCube-250708A: No Candidates from WINTER
  70. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  71. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  72. IceCube-250706A: No Candidates from WINTER
  73. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  74. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  75. IceCube-250708A: Global MASTER-Net observations report
  76. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-250706A: EP-FXT follow-up observations
  78. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  79. IceCube-250706A: Global MASTER-Net observations report
  80. IceCube-250416A: DDOTI Optical Upper Limit
  81. IceCube-250706A: COLIBRÍ optical upper limits
  82. IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
  83. IceCube alert 141029_8144692 retraction
  84. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  85. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  86. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  87. IceCube-250506A - IceCube observation of a high-energy neutrino candidate track-like event
  88. IceCube Alert 250506.59: Global MASTER-Net observations report
  89. Fermi-LAT Gamma-ray Observations of IceCube-250429A
  90. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  91. IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-250429A - IceCube observation of a high-energy neutrino candidate track-like event
  93. Fermi-LAT Gamma-ray Observations of IceCube-250426A
  94. IceCube Alert 250426.74: Global MASTER-Net observations report
  95. IceCube-250426A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  96. IceCube-250426A - IceCube observation of a high-energy neutrino candidate track-like event
  97. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  98. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  99. Fermi-LAT gamma-ray observations of IceCube-250421A
  100. IceCube-250421A: DDOTI Detection of the LAST Candidate

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Download all Circulars as a .tar.gz archive (updated once a day):
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