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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"

1526 results found.

  1. IceCube Alert 210922.76: Global MASTER-Net observations report
  2. IceCube-210922A - IceCube observation of a high-energy neutrino candidate track-like event
  3. IceCube-210811A: Upper limits from a search for additional neutrino events in IceCube
  4. IceCube-210730A: not observable by Fermi-GBM
  5. IceCube-210811A: Upper limits from Fermi-GBM Observations
  6. IceCube-210811A: No Candidate Counterparts from the Zwicky Transient Facility
  7. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  8. IceCube-210811A - IceCube observation of a high-energy neutrino candidate track-like event
  9. IceCube Alert 210811.09: Global MASTER-Net observations report
  10. IceCube-210730A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  11. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  12. IceCube-210730A - IceCube observation of a high-energy neutrino candidate track-like event
  13. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  14. IceCube-210717A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  15. IceCube-210717A: IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-210629A - Spectroscopic observation of AT2021osi
  17. IceCube-210516A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  18. IceCube-210510A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  19. IceCube-210629A: Upper limits from a search for additional neutrino events in IceCube
  20. IceCube-210629A: One Candidate Counterpart from the Zwicky Transient Facility
  21. IceCube-210629A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  22. Fermi-LAT Gamma-ray Observations of IceCube-210629A
  23. IceCube-210629A: Upper limits from Fermi-GBM Observations
  24. IceCube Alert 210629.76: Global MASTER-Net observations report
  25. IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
  26. Fermi-LAT Gamma-ray Observations of IceCube-210608A
  27. IceCube-210608A: not observable by Fermi-GBM
  28. IceCube-210608A: IceCube observation of a high-energy neutrino candidate track-like event
  29. IceCube Alert 210608.15: Global MASTER-Net observations report
  30. IceCube GCN alert 135302_36915486.amon retraction
  31. IceCube Alert 210519.86: Global MASTER-Net observations report
  32. Fermi-LAT Gamma-ray Observations of IceCube-210516A
  33. IceCube Alert 210515.01: Global MASTER-Net observations report
  34. IceCube-210516A: No significant detection in HAWC
  35. IceCube-210516A: Upper limits from a search for additional neutrino events in IceCube
  36. IceCube Alert 210516.61: Global MASTER-Net observations report
  37. IceCube-210516A - IceCube observation of a high-energy neutrino candidate track-like event
  38. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEM-210515A and 210515B
  39. IceCube-210510A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-210510A: not observable by Fermi-GBM
  41. IceCube-210510A: No candidate counterparts from the Zwicky Transient Facility
  42. Fermi-LAT Gamma-ray Observations of IceCube-210510A
  43. IceCube Alert 210510.20: Global MASTER-Net observations report
  44. IceCube-210510A: DDOTI Upper Limits
  45. IceCube-210510A - IceCube observation of a high-energy neutrino candidate track-like event
  46. Fermi-LAT Gamma-ray Observations of IceCube-210503A and detection of a new gamma-ray source, Fermi J0931.9+3633
  47. IceCube-210503A: IceCube observation of a high-energy neutrino candidate event
  48. IceCube Alert 210416.09: Global MASTER-Net observations report
  49. IceCubeCascade-210416a: Kanata Optical Imaging of 3C 279
  50. IceCube Alert 210322.11: Global MASTER-Net observations report
  51. IceCube 135113_19489408.amon: Swift-XRT observations
  52. IceCube Astrotrack Bronze 135113_19489408.amon is likely background
  53. IceCube-210210A: Two Additional Optical Candidate Counterparts Found by DECam
  54. IceCube alert 134994_1103075 retraction
  55. IceCube Alert 210213.78: Global MASTER-Net observations report
  56. IceCube-210210A: Four Candidate Optical Counterparts from DECam Observations
  57. IceCube-210210A: Upper limits from a search for additional neutrino events in IceCube
  58. Swift-XRT observations of IceCube-210210A
  59. IceCube-210210A: No neutrino counterpart in ANTARES
  60. Fermi-LAT Gamma-ray Observations of IceCube-210210A
  61. IceCube Alert 210210.50: Global MASTER-Net observations report
  62. IceCube-210210A: Upper limits from Fermi-GBM Observations
  63. IceCube-210210A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  64. IceCube-210210A: Two Candidate Counterparts from the Zwicky Transient Facility
  65. IceCube-210210A: IceCube observation of a high-energy neutrino candidate event
  66. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-210111A
  67. IceCube-201222A: No Candidate Counterparts from the Zwicky Transient Facility
  68. Swift-XRT observations of Icecube 201222A
  69. IceCube-201222A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-201221A: Upper limits from a search for additional neutrino events in IceCube
  71. IceCube-201222A: No significant detection in HAWC
  72. IceCube-201221A: No significant detection in HAWC
  73. IceCube-201221A: Upper limits from Insight-HXMT/HE observations
  74. Fermi-LAT Gamma-ray Observations of IceCube-201222A
  75. Fermi-LAT Gamma-ray Observations of IceCube-201221A
  76. IceCube-201222A: not observable by Fermi-GBM
  77. IceCube-201222A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  78. IceCube Alert 201222.04: Global MASTER-Net observations report
  79. IceCube-201222A: IceCube observation of a high-energy neutrino candidate event
  80. IceCube-201221A: not observable by Fermi-GBM
  81. IceCube-201221A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  82. IceCube-201221A: IceCube observation of a high-energy neutrino candidate event
  83. IceCube-201209A : MAXI/GSC upper limit
  84. IceCube-201209A: Upper limits from Insight-HXMT/HE observations
  85. IceCube-201209: No significant detection in HAWC
  86. IceCube-201209A: No Candidate Counterparts from the Zwicky Transient Facility
  87. IceCube-201209A: Upper limits from a search for additional neutrino events in IceCube
  88. IceCube-201209A: Upper limits from Fermi-GBM Observations
  89. Fermi-LAT Gamma-ray Observations of IceCube-201209A
  90. IceCube-201209A: No neutrino counterpart candidates in ANTARES search
  91. IceCube Alert 201209.43: Global MASTER-Net observations report
  92. IceCube-201209A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  93. IceCube-201209A: IceCube observation of a high-energy neutrino candidate event
  94. IceCube-201130A: Optical and NIR Imaging Follow-up by Kanata Telescope
  95. Swift follow-up observations of the flat spectrum radio quasar PMN J0206-1150 in the error region of IceCube-201130A
  96. IceCube-201130A: No Candidate Counterparts from the Zwicky Transient Facility
  97. IceCube-201130A: No significant detection in HAWC
  98. IceCube-201130A: Upper limits from a search for additional neutrino events in IceCube
  99. IceCube-201130A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  100. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A

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