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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"

1529 results found.

  1. IceCube-201130A: Upper limits from a search for additional neutrino events in IceCube
  2. IceCube-201130A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  3. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  4. Fermi-LAT Gamma-ray Observations of IceCube-201130A
  5. IceCube-201130A: Not observable by Fermi-GBM
  6. Swift-XRT observations of IceCube 201130A
  7. IceCube-201130A: IceCube observation of a high-energy neutrino candidate event
  8. IceCube Alert 201130.85: Global MASTER-Net observations report
  9. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  10. IceCube-201120A in the Cygnus region: No enhanced TeV gamma-ray flux detected by HAWC
  11. IceCube Alert 201124.34: Global MASTER-Net observations report
  12. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  13. IceCube-201114A: DECam observations and candidate optical counterpart
  14. IceCube-201120A: Upper limits from a search for additional neutrino events in IceCube
  15. Fermi-LAT Gamma-ray Observations of IceCube-201120A
  16. IceCube-201120A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  17. IceCube-201120A: Swift-XRT non-detection of 4FGL J2028.6+4110e
  18. IceCube-201120A: Upper limits from Fermi-GBM Observations
  19. IceCube Alert 201120.41: Global MASTER-Net observations report
  20. IceCube-201120A: IceCube observation of a high-energy neutrino candidate event
  21. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  22. Fermi-LAT Gamma-ray Observations of IceCube-201114A
  23. IceCube Alert 201115.67: Global MASTER-Net observations report
  24. IceCube-201115A: Upper limits from a search for additional neutrino events in IceCube
  25. IceCube-201114A: Upper limits from a search for additional neutrino events in IceCube
  26. IceCube-201115A: No significant detection in HAWC
  27. IceCube-201114A: No significant detection in HAWC
  28. IceCube-201115A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  29. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  30. IceCube-201115A: No neutrino counterpart candidates in ANTARES search
  31. IceCube Alert 201115.09: Global MASTER-Net observations report
  32. Fermi-LAT Gamma-ray Observations of IceCube-201115A
  33. IceCube-201115A: not observable by Fermi-GBM
  34. Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
  35. IceCube-201114A: Upper limits from Fermi GBM Observations
  36. VLASS identifies possible radio counterparts to IceCube-201115A, including a bright BL Lac candidate
  37. IceCube GCN alert 134701_49508272.amon retraction
  38. Swift-XRT observations of IceCube 201114A
  39. IceCube-201114A: No neutrino counterpart candidates in ANTARES search
  40. IceCube-201115A: IceCube observation of a high-energy neutrino candidate event
  41. IceCube Alert 201114.63: Global MASTER-Net observations report
  42. IceCube-201114A - IceCube observation of a high-energy neutrino candidate event
  43. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  44. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  45. IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
  46. IceCube-201021A: No significant detection in HAWC
  47. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  48. IceCube-201021A: Optical counterpart of WISEA J172314.13+142101.5
  49. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  50. Swift-XRT observations of IceCube 201021A (2)
  51. IceCube-201021A: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-201021A: No neutrino counterpart candidates in ANTARES search
  53. IceCube-201021A: Upper limits from Fermi-GBM Observations
  54. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  55. Swift-XRT observations of IceCube 201021A
  56. IceCube Alert 201021.28: Global MASTER-Net observations report
  57. IceCube-201021A: IceCube observation of a high-energy neutrino candidate event
  58. IceCube-201014A: No significant detection in HAWC
  59. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube Alert 201014.09: Global MASTER-Net observations report
  61. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  62. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  63. IceCube-201014A: Not observable by GBM
  64. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  65. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  66. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  67. IceCube-200929A: JCMT/SCUBA2 observations
  68. IceCube-201007A: No significant detection in HAWC
  69. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-200926A: Upper limits from Insight-HXMT Observations
  71. IceCube-201007A: Upper limits from Fermi-GBM Observations
  72. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  73. Swift-XRT observations of IceCube 201007A
  74. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  75. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  76. IceCube Alert 201007.92: Global MASTER-Net observations report
  77. IceCube-200926A: No usable INTEGRAL data
  78. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  79. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  80. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  81. IceCube-200926A: JCMT/SCUBA2 observations
  82. IceCube-200929A: No significant detection in HAWC
  83. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  84. Swift-XRT observations of IceCube 200929A
  85. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  86. IceCube-200929A: Upper limits from Fermi-GBM Observations
  87. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  88. IceCube-200926B: No significant detection in HAWC
  89. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  90. IceCube-200926B: Upper limits from Fermi-GBM Observations
  91. IceCube-200926A: Upper limits from Fermi-GBM Observations
  92. IceCube Alert 200929.74: Global MASTER-Net observations report
  93. IceCube-200926A: No significant detection in HAWC
  94. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  95. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  96. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  97. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  98. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  99. IceCube Alert 200926.94: Global MASTER-Net observations report
  100. Swift-XRT observations of IceCube 200926A

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