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

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