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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"

1338 results found.

  1. IceCube-220303A: No significant detection in HAWC
  2. IceCube-220306A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube-220304A: Upper limits from a search for additional neutrino events in IceCube
  4. Fermi-LAT Gamma-ray Observations of IceCube-220306A
  5. Fermi-LAT Gamma-ray Observations of IceCube-220304A
  6. IceCube-220306A - IceCube observation of a high-energy neutrino candidate track-like event
  7. IceCube-220303A: One X-ray counterpart from Swift/XRT follow up observations
  8. IceCube-220303A: Upper limits from a search for additional neutrino events in IceCube
  9. Fermi-LAT Gamma-ray Observations of IceCube-220303A
  10. IceCube-220304A - IceCube observation of a high-energy neutrino candidate track-like event
  11. IceCube Alert 220304.74: Global MASTER-Net observations report
  12. Tev Blazar as possible optical counterpart of the high-energy neutrino IceCube-220303A
  13. IceCube Alert 220303.75: Global MASTER-Net observations report
  14. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  15. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  16. Fermi-LAT Gamma-ray Observations of IceCube-220225A
  17. IceCube Alert 220225.59: Global MASTER-Net observations report
  18. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  19. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  20. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  21. IceCube Alert 220221.03: Global MASTER-Net observations report
  22. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  23. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  24. IceCube Alert 220220.60: Global MASTER-Net observations report
  25. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  26. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  27. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  28. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  29. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  30. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  31. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  32. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  33. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  34. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  35. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  36. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  37. IceCube Alert 220202.49: Global MASTER-Net observations report
  38. IceCube-211208A: the optical observation of the candidate PKS0735+178
  39. Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
  40. IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube
  41. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  42. IceCube Alert 220115.51: Global MASTER-Net observations report
  43. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  44. IceCube-20211216B: observations of SN2021gpw in the errorbox of the neutrino trigger
  45. IceCube-211216B: No significant detection in HAWC
  46. IceCube-211216A: No significant detection in HAWC
  47. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  48. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  49. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  50. IceCube-211216B: Upper limits from Fermi-GBM Observations
  51. IceCube-211216A: Upper limits from Fermi-GBM Observations
  52. IceCube-211216A: Upper limits from a search for additional neutrino events in IceCube
  53. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  54. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube Alert 211216.99: Global MASTER-Net observations report
  56. IceCube Alert 211216.30: Global MASTER-Net observations report
  57. IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  58. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube-211208A: No neutrino counterpart detected with ANTARES
  60. IceCube-211208A: No significant detection in HAWC
  61. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  62. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  63. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  64. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211209A
  65. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube Alert 211208.84: Global MASTER-Net observations report
  67. IceCube-211125A: No significant detection in HAWC
  68. IceCube-Cascade 211128A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube-211125A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  71. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  72. IceCube-211125A: No neutrino counterpart detected with ANTARES
  73. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube Alert 211125.27: Global MASTER-Net observations report
  75. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  76. IceCube-211123A: Upper limits from a search for additional neutrino events in IceCube
  77. IceCube-211123A: INTEGRAL was inactive at the time of the event
  78. IceCube-211123A: Upper limits from Fermi-GBM Observations
  79. IceCube-211117A: not observable by Fermi-GBM
  80. IceCube-211116A: not observable by Fermi-GBM
  81. IceCube-211023A: not observable by Fermi-GBM
  82. IceCube Alert 211123.60: Global MASTER-Net observations report
  83. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  84. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  85. Search for counterpart to IceCube-211117A with ANTARES
  86. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  87. IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
  88. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  89. IceCube-211116A: No neutrino counterpart detected with ANTARES
  90. IceCube Alert 211116.44: Global MASTER-Net observations report
  91. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  92. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  93. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  94. IceCube-211023A: No neutrino counterpart detected with ANTARES
  95. IceCube Alert 211023.36: Global MASTER-Net observations report
  96. IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event
  97. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211020A
  98. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  99. IceCube-20210922A: No optical counterparts found by MITSuME observations
  100. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations

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