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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. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  2. Fermi-LAT Gamma-ray Observations of IceCube-201130A
  3. IceCube-201130A: Not observable by Fermi-GBM
  4. Swift-XRT observations of IceCube 201130A
  5. IceCube-201130A: IceCube observation of a high-energy neutrino candidate event
  6. IceCube Alert 201130.85: Global MASTER-Net observations report
  7. IceCube-201114A: Updated photometry for three DECam candidate optical counterparts
  8. IceCube-201120A in the Cygnus region: No enhanced TeV gamma-ray flux detected by HAWC
  9. IceCube Alert 201124.34: Global MASTER-Net observations report
  10. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A
  11. IceCube-201114A: DECam observations and candidate optical counterpart
  12. IceCube-201120A: Upper limits from a search for additional neutrino events in IceCube
  13. Fermi-LAT Gamma-ray Observations of IceCube-201120A
  14. IceCube-201120A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  15. IceCube-201120A: Swift-XRT non-detection of 4FGL J2028.6+4110e
  16. IceCube-201120A: Upper limits from Fermi-GBM Observations
  17. IceCube Alert 201120.41: Global MASTER-Net observations report
  18. IceCube-201120A: IceCube observation of a high-energy neutrino candidate event
  19. IceCube 201114A: Swift followup of Fermi J0703.5+0505
  20. Fermi-LAT Gamma-ray Observations of IceCube-201114A
  21. IceCube Alert 201115.67: Global MASTER-Net observations report
  22. IceCube-201115A: Upper limits from a search for additional neutrino events in IceCube
  23. IceCube-201114A: Upper limits from a search for additional neutrino events in IceCube
  24. IceCube-201115A: No significant detection in HAWC
  25. IceCube-201114A: No significant detection in HAWC
  26. IceCube-201115A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  27. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  28. IceCube-201115A: No neutrino counterpart candidates in ANTARES search
  29. IceCube Alert 201115.09: Global MASTER-Net observations report
  30. Fermi-LAT Gamma-ray Observations of IceCube-201115A
  31. IceCube-201115A: not observable by Fermi-GBM
  32. Swift XRT observations of the Fermi-LAT source 4FGL J0658.6+0636, positionally consistent with the IceCube high-energy neutrino alert
  33. IceCube-201114A: Upper limits from Fermi GBM Observations
  34. VLASS identifies possible radio counterparts to IceCube-201115A, including a bright BL Lac candidate
  35. IceCube GCN alert 134701_49508272.amon retraction
  36. Swift-XRT observations of IceCube 201114A
  37. IceCube-201114A: No neutrino counterpart candidates in ANTARES search
  38. IceCube-201115A: IceCube observation of a high-energy neutrino candidate event
  39. IceCube Alert 201114.63: Global MASTER-Net observations report
  40. IceCube-201114A - IceCube observation of a high-energy neutrino candidate event
  41. Fermi-LAT Gamma-ray Observations of NuEm-201107A
  42. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201107A
  43. IceCube 201021A: Swift follow-up of Fermi J1725.5+1312
  44. IceCube-201021A: No significant detection in HAWC
  45. IceCube-201021A: One candidate counterpart from the Zwicky Transient Facility
  46. IceCube-201021A: Optical counterpart of WISEA J172314.13+142101.5
  47. Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
  48. Swift-XRT observations of IceCube 201021A (2)
  49. IceCube-201021A: Upper limits from a search for additional neutrino events in IceCube
  50. IceCube-201021A: No neutrino counterpart candidates in ANTARES search
  51. IceCube-201021A: Upper limits from Fermi-GBM Observations
  52. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  53. Swift-XRT observations of IceCube 201021A
  54. IceCube Alert 201021.28: Global MASTER-Net observations report
  55. IceCube-201021A: IceCube observation of a high-energy neutrino candidate event
  56. IceCube-201014A: No significant detection in HAWC
  57. IceCube-201014A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube Alert 201014.09: Global MASTER-Net observations report
  59. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  60. Fermi-LAT Gamma-ray Observations of IceCube-201014A
  61. IceCube-201014A: Not observable by GBM
  62. IceCube-201014A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  63. IceCube-201014A - IceCube observation of a high-energy neutrino candidate track-like event
  64. IceCube-201007A: No candidate counterparts from the Zwicky Transient Facility
  65. IceCube-200929A: JCMT/SCUBA2 observations
  66. IceCube-201007A: No significant detection in HAWC
  67. IceCube-201007A: Upper limits from a search for additional neutrino events in IceCube
  68. IceCube-200926A: Upper limits from Insight-HXMT Observations
  69. IceCube-201007A: Upper limits from Fermi-GBM Observations
  70. Fermi-LAT Gamma-ray Observations of IceCube-201007A
  71. Swift-XRT observations of IceCube 201007A
  72. IceCube-201007A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  73. IceCube-201007A - IceCube observation of a high-energy neutrino candidate track-like event
  74. IceCube Alert 201007.92: Global MASTER-Net observations report
  75. IceCube-200926A: No usable INTEGRAL data
  76. IceCube-200926B: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  77. IceCube-200929A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  78. IceCube-200926A: No candidate counterparts from the Zwicky Transient Facility
  79. IceCube-200926A: JCMT/SCUBA2 observations
  80. IceCube-200929A: No significant detection in HAWC
  81. IceCube-200929A: Upper limits from a search for additional neutrino events in IceCube
  82. Swift-XRT observations of IceCube 200929A
  83. Fermi-LAT Gamma-ray Observations of IceCube-200929A
  84. IceCube-200929A: Upper limits from Fermi-GBM Observations
  85. IceCube-200929A: No neutrino counterpart candidates in ANTARES search
  86. IceCube-200926B: No significant detection in HAWC
  87. IceCube-200929A: IceCube observation of a high-energy neutrino candidate event
  88. IceCube-200926B: Upper limits from Fermi-GBM Observations
  89. IceCube-200926A: Upper limits from Fermi-GBM Observations
  90. IceCube Alert 200929.74: Global MASTER-Net observations report
  91. IceCube-200926A: No significant detection in HAWC
  92. IceCube-200926B: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-200926A: Upper limits from a search for additional neutrino events in IceCube
  94. IceCube-200926A: No Candidate Counterparts from the Zwicky Transient Facility
  95. Fermi-LAT Gamma-ray Observations of IceCube-200926B
  96. IceCube-200926B: No neutrino counterpart candidates in ANTARES search
  97. IceCube Alert 200926.94: Global MASTER-Net observations report
  98. Swift-XRT observations of IceCube 200926A
  99. Fermi-LAT Gamma-ray Observations of IceCube-200926A
  100. IceCube Alert 200926.33: Global MASTER-Net observations report

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