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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"

1518 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  2. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-251218A: COLIBRÍ optical upper limits
  4. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  5. IceCube Alert 251218.85: Global MASTER-Net observations report
  6. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  7. Fermi-LAT Gamma-ray Observations of IceCube-251210A
  8. IceCube-251210A: Upper limits from a search for additional neutrino events in IceCube
  9. IceCube-251210A: DDOTI Optical Upper Limit
  10. IceCube Alert 251210.46: Global MASTER-Net observations report
  11. IceCube-251210A - IceCube observation of a high-energy neutrino candidate track-like event
  12. Fermi-LAT Gamma-ray Observations of IceCube-251130A
  13. IceCube-251130A: Upper limits from a search for additional neutrino events in IceCube
  14. IceCube Alert 251130.75: Global MASTER-Net observations report
  15. IceCube-251130A - IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube
  17. LIGO/Virgo/KAGRA S251108fi: DDOTI Optical Candidate
  18. LIGO/Virgo/KAGRA S251108fi: One counterpart neutrino candidate from IceCube neutrino searches
  19. IceCube-Cascade 251107A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-251025A: Two Transient Candidates from the Zwicky Transient Facility
  21. IceCube-251025A: Upper limits from a search for additional neutrino events in IceCube
  22. Fermi-LAT Gamma-ray Observations of IceCube-251025A
  23. IceCube-251025A: DDOTI Optical Upper Limit
  24. IceCube Alert 251025.57: Global MASTER-Net observations report
  25. IceCube-251025A - IceCube observation of a high-energy neutrino candidate track-like event
  26. Fermi-LAT gamma-ray observations of IceCube-251018A
  27. IceCube-251018A: Upper limits from a search for additional neutrino events in IceCube
  28. IceCube-251018A: DDOTI Optical Upper Limit
  29. IceCube-251018A: Global MASTER-Net observations report
  30. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event
  31. IceCube-251018A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  32. Upper limits from a search for additional neutrino events in IceCube
  33. IceCube Alert 251014.77: Global MASTER-Net observations report
  34. Fermi-LAT Gamma-ray Observations of IceCube-251014A
  35. IceCube-251014A - IceCube observation of a high-energy neutrino candidate track-like event
  36. IceCube alert 141456_888784 retraction
  37. IceCube Alert 251008A: Global MASTER-Net observations report
  38. Fermi-LAT Gamma-ray Observations of IceCube-250926A
  39. IceCube-250926A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube Alert 250926.52: Global MASTER-Net observations report
  41. IceCube-250926A - IceCube observation of a high-energy neutrino candidate track-like event
  42. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  43. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  44. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  45. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  46. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  47. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  48. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  49. IceCube Alert 250905.84: Global MASTER-Net observations report
  50. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  51. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  52. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  53. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  54. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  55. IceCube Alert 250831.75: Global MASTER-Net observations report
  56. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  57. IceCube-250813A: Upper limits from a search for additional neutrino events in IceCube
  58. Fermi-LAT Gamma-ray Observations of IceCube-250813A
  59. IceCube-250813A - IceCube observation of a high-energy neutrino candidate track-like event
  60. IceCube Alert 250813.14: Global MASTER-Net observations report
  61. IceCube-Cascade 250809A: Upper limits from a search for additional neutrino events in IceCube
  62. Fermi-LAT Gamma-ray Observations of IceCube-250804A
  63. IceCube-250804A: Upper limits from a search for additional neutrino events in IceCube
  64. IceCube-Cascade 250804A: Upper limits from a search for additional neutrino events in IceCube
  65. IceCube Alert 250804.84: Global MASTER-Net observations report
  66. IceCube-250804A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube-250708A: No Candidates from WINTER
  68. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  69. IceCube-250708A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-250706A: No Candidates from WINTER
  71. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  72. IceCube-250708A - IceCube observation of a high-energy neutrino candidate track-like event
  73. IceCube-250708A: Global MASTER-Net observations report
  74. IceCube-250706A: Upper limits from a search for additional neutrino events in IceCube
  75. IceCube-250706A: EP-FXT follow-up observations
  76. Fermi-LAT Gamma-ray Observations of IceCube-250706A
  77. IceCube-250706A: Global MASTER-Net observations report
  78. IceCube-250416A: DDOTI Optical Upper Limit
  79. IceCube-250706A: COLIBRÍ optical upper limits
  80. IceCube-250706A - IceCube observation of a high-energy neutrino candidate track-like event
  81. IceCube alert 141029_8144692 retraction
  82. IceCube-250506A: No Transient Candidates from the Zwicky Transient Facility
  83. IceCube-250506A: Upper limits from a search for additional neutrino events in IceCube
  84. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  85. IceCube-250506A - IceCube observation of a high-energy neutrino candidate track-like event
  86. IceCube Alert 250506.59: Global MASTER-Net observations report
  87. Fermi-LAT Gamma-ray Observations of IceCube-250429A
  88. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  89. IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube
  90. IceCube-250429A - IceCube observation of a high-energy neutrino candidate track-like event
  91. Fermi-LAT Gamma-ray Observations of IceCube-250426A
  92. IceCube Alert 250426.74: Global MASTER-Net observations report
  93. IceCube-250426A - IceCube observation of a high-energy neutrino candidate track-like event (duplicate submission)
  94. IceCube-250426A - IceCube observation of a high-energy neutrino candidate track-like event
  95. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  96. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  97. Fermi-LAT gamma-ray observations of IceCube-250421A
  98. IceCube-250421A: DDOTI Detection of the LAST Candidate
  99. IC-250421A: LAST optical observations of the IceCube neutrino candidate
  100. IceCube Alert 250421.71: Global MASTER-Net observations report

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