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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"

1527 results found.

  1. Tev Blazar as possible optical counterpart of the high-energy neutrino IceCube-220303A
  2. IceCube Alert 220303.75: Global MASTER-Net observations report
  3. IceCube-220303A - IceCube observation of a high-energy neutrino candidate track-like event
  4. IceCube-220225A: Upper limits from a search for additional neutrino events in IceCube
  5. Fermi-LAT Gamma-ray Observations of IceCube-220225A
  6. IceCube Alert 220225.59: Global MASTER-Net observations report
  7. IceCube-220225A - IceCube observation of a high-energy neutrino candidate track-like event
  8. IceCube-220221A: Upper limits from a search for additional neutrino events in IceCube
  9. Fermi-LAT Gamma-ray Observations of IceCube-220221A
  10. IceCube Alert 220221.03: Global MASTER-Net observations report
  11. IceCube Alert 220220.60:NuEm-220220A: MASTER optical possible counterpart
  12. IceCube-220221A - IceCube observation of a high-energy neutrino candidate track-like event
  13. IceCube Alert 220220.60: Global MASTER-Net observations report
  14. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220220A
  15. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-220212A
  16. IceCube-220205B: Upper limits from a search for additional neutrino events in IceCube
  17. IceCube-220205A: Upper limits from a search for additional neutrino events in IceCube
  18. Fermi-LAT Gamma-ray Observations of IceCube-220205B
  19. Fermi-LAT Gamma-ray Observations of IceCube-220205A
  20. IceCube-220205B: No neutrino counterpart candidates in ANTARES search
  21. IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
  22. IceCube-220205A - IceCube observation of a high-energy neutrino candidate track-like event
  23. Fermi-LAT Gamma-ray Observations of IceCube-220202A
  24. IceCube-220202A: Upper limits from a search for additional neutrino events in IceCube
  25. IceCube-220202A: IceCube observation of a high-energy neutrino candidate track-like event
  26. IceCube Alert 220202.49: Global MASTER-Net observations report
  27. IceCube-211208A: the optical observation of the candidate PKS0735+178
  28. Fermi-LAT-ANTARES 220121a: upper limits from a search for coincident neutrinos with IceCube
  29. IceCube-220115A: Upper limits from a search for additional neutrino events in IceCube
  30. Fermi-LAT Gamma-ray Observations of IceCube-220115A and detection of a new gamma-ray source, Fermi J2350.2+2620
  31. IceCube Alert 220115.51: Global MASTER-Net observations report
  32. IceCube-220115A - IceCube observation of a high-energy neutrino candidate track-like event
  33. IceCube-20211216B: observations of SN2021gpw in the errorbox of the neutrino trigger
  34. IceCube-211216B: No significant detection in HAWC
  35. IceCube-211216A: No significant detection in HAWC
  36. IceCube-211216B: No neutrino counterpart candidates in ANTARES search
  37. Fermi-LAT Gamma-ray Observations of IceCube-211216B
  38. Fermi-LAT Gamma-ray Observations of IceCube-211216A
  39. IceCube-211216B: Upper limits from Fermi-GBM Observations
  40. IceCube-211216A: Upper limits from Fermi-GBM Observations
  41. IceCube-211216A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-211216A: No neutrino counterpart candidates in ANTARES search
  43. IceCube-211216B - IceCube observation of a high-energy neutrino candidate track-like event
  44. IceCube Alert 211216.99: Global MASTER-Net observations report
  45. IceCube Alert 211216.30: Global MASTER-Net observations report
  46. IceCube-211216A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  47. IceCube-211216A - IceCube observation of a high-energy neutrino candidate track-like event
  48. IceCube-211208A: No neutrino counterpart detected with ANTARES
  49. IceCube-211208A: No significant detection in HAWC
  50. IceCube-211208A: Upper limits from a search for additional neutrino events in IceCube
  51. Fermi-LAT Gamma-ray Observations of IceCube-211208A
  52. IceCube-211208A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  53. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211209A
  54. IceCube-211208A - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube Alert 211208.84: Global MASTER-Net observations report
  56. IceCube-211125A: No significant detection in HAWC
  57. IceCube-Cascade 211128A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube-211125A: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-211125A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  60. Fermi-LAT Gamma-ray Observations of IceCube-211125A
  61. IceCube-211125A: No neutrino counterpart detected with ANTARES
  62. IceCube-211125A: IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube Alert 211125.27: Global MASTER-Net observations report
  64. Fermi-LAT Gamma-ray Observations of IceCube-211123A
  65. IceCube-211123A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-211123A: INTEGRAL was inactive at the time of the event
  67. IceCube-211123A: Upper limits from Fermi-GBM Observations
  68. IceCube-211117A: not observable by Fermi-GBM
  69. IceCube-211116A: not observable by Fermi-GBM
  70. IceCube-211023A: not observable by Fermi-GBM
  71. IceCube Alert 211123.60: Global MASTER-Net observations report
  72. IceCube-211123A - IceCube observation of a high-energy neutrino candidate track-like event
  73. Fermi-LAT Gamma-ray Observations of IceCube-211117A
  74. Search for counterpart to IceCube-211117A with ANTARES
  75. IceCube-211117A : IceCube observation of a high-energy neutrino candidate track-like event
  76. IceCube-211116A: Upper limits from a search for additional neutrino events in IceCube
  77. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  78. IceCube-211116A: No neutrino counterpart detected with ANTARES
  79. IceCube Alert 211116.44: Global MASTER-Net observations report
  80. IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event
  81. IceCube-211023A: Upper limits from a search for additional neutrino events in IceCube
  82. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  83. IceCube-211023A: No neutrino counterpart detected with ANTARES
  84. IceCube Alert 211023.36: Global MASTER-Net observations report
  85. IceCube-211023A - IceCube observation of a high-energy neutrino candidate track-like event
  86. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-211020A
  87. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  88. IceCube-20210922A: No optical counterparts found by MITSuME observations
  89. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  90. IceCube-210922A: DESI Observations
  91. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  92. IceCube-210922A: SMA observation for the JCMT candidate
  93. IceCube-210926A: No neutrino counterpart candidates in ANTARES search
  94. IceCube-210922A: JCMT/SCUBA2 observations
  95. IceCube-210922A: No Candidate Counterparts from Swift/XRT follow up observations
  96. IceCube-210922A: No significant detection in HAWC
  97. IceCube-210922A: No neutrino counterpart candidates in ANTARES search
  98. IceCube-210922A: Upper limits from a search for additional neutrino events in IceCube
  99. IceCube-210922A: Upper limits from Fermi-GBM Observations
  100. IceCube-210922A: No Candidate Counterparts from the Zwicky Transient Facility

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