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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. LIGO/Virgo/KAGRA S241102o: 1 counterpart neutrino candidate event from an IceCube neutrino search
  2. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  3. IceCube alert 139977_2910365 retraction
  4. IceCube Alert 241016.04: Global MASTER-Net observations report
  5. IceCube-241006A: Upper limits from a search for additional neutrino events in IceCube
  6. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  7. IceCube-241006A: No candidates from the Zwicky Transient Facility
  8. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  9. IceCube Alert 241006.94: Global MASTER-Net observations report
  10. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  11. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  12. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  13. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  14. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  15. AMON NuEM 240926A: Swift XRT Follow-up
  16. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  17. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  18. GRB 240825A: Upper limits from a neutrino search with IceCube
  19. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  20. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  21. Fermi-LAT gamma-ray observations of IceCube-240808A
  22. IceCube Alert 240808.27: Global MASTER-Net observations report
  23. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  24. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  25. Fermi-LAT gamma-ray observations of IceCube-240725A
  26. IceCube Alert 240725.22: Global MASTER-Net observations report
  27. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  28. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  29. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  30. Fermi-LAT gamma-ray observations of IceCube-240721A
  31. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  32. IceCube Alert 240721.68: Global MASTER-Net observations report
  33. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  34. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  35. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  36. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  38. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  39. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  40. Fermi-LAT gamma-ray observations of IceCube-240424A
  41. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  43. IceCube Alert 240424.08: Global MASTER-Net observations report
  44. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  45. Fermi-LAT gamma-ray observations of IceCube-240419A
  46. IceCube Alert 240419.98: Global MASTER-Net observations report
  47. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  48. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  49. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  50. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  51. Fermi-LAT gamma-ray observations of IceCube-240412A
  52. IceCube Alert 240412.23: Global MASTER-Net observations report
  53. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  54. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  55. Fermi-LAT gamma-ray observations of IceCube-240327B
  56. Fermi-LAT gamma-ray observations of IceCube-240327A
  57. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  58. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  59. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube-240327B: No candidates from the Zwicky Transient Facility
  61. IceCube Alert 240327.68: Global MASTER-Net observations report
  62. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  64. Fermi-LAT gamma-ray observations of IceCube-240307A
  65. IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube Alert 240307.32: Global MASTER-Net observations report
  68. Fermi-LAT gamma-ray observations of IceCube-240229A
  69. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  70. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  71. IceCube Alert 240229.66: Global MASTER-Net observations report
  72. Fermi-LAT gamma-ray observations of IceCube-240204A
  73. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  74. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  75. IceCube Alert 240204.38: Global MASTER-Net observations report
  76. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  77. Fermi-LAT gamma-ray observations of IceCube-240123A
  78. IceCube Alert 240123.48: Global MASTER-Net observations report
  79. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  80. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  81. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A: correction on the localization
  82. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  83. IceCube-240105A: ZTF optical observation of blazar PKS 0446+11
  84. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  85. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  86. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  87. IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
  88. Update of IceCube-240105A - Corrected errors
  89. IceCube Alert 240105.52: Global MASTER-Net observations report
  90. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  91. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-231211A: GRANDMA observations of PKS2047+098
  93. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  94. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  95. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  96. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  97. IceCube Alert 231211.03: Global MASTER-Net observations report
  98. IceCube-231202A: No candidates from the Zwicky Transient Facility
  99. Fermi-LAT gamma-ray observations of IceCube-231202A
  100. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search

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