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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"

1519 results found.

  1. IceCube Alert 241006.94: Global MASTER-Net observations report
  2. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  3. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  4. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  5. IceCube-240929A: Upper limits from a search for additional neutrino events in IceCube
  6. LIGO/Virgo/KAGRA S240930df: 1 counterpart neutrino candidate event from an IceCube neutrino search
  7. AMON NuEM 240926A: Swift XRT Follow-up
  8. IceCube-240929A - IceCube observation of a high-energy neutrino candidate track-like event
  9. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240926A
  10. GRB 240825A: Upper limits from a neutrino search with IceCube
  11. IceCube-240721A: AT2023qqp and AT2024pge likely unrelated
  12. IceCube-240808A: Upper limits from a search for additional neutrino events in IceCube
  13. Fermi-LAT gamma-ray observations of IceCube-240808A
  14. IceCube Alert 240808.27: Global MASTER-Net observations report
  15. IceCube-240808A - IceCube observation of a high-energy neutrino candidate track-like event
  16. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  17. Fermi-LAT gamma-ray observations of IceCube-240725A
  18. IceCube Alert 240725.22: Global MASTER-Net observations report
  19. IceCube-240725A - IceCube observation of a high-energy neutrino candidate track-like event
  20. IceCube-240721A: Two candidates from the Zwicky Transient Facility
  21. IceCube-240721A: Upper limits from a search for additional neutrino events in IceCube
  22. Fermi-LAT gamma-ray observations of IceCube-240721A
  23. IceCube-240721A - IceCube observation of a high-energy neutrino candidate track-like event
  24. IceCube Alert 240721.68: Global MASTER-Net observations report
  25. IceCube-Cascade 240714A: TRT optical observations on the EP/FXT positions
  26. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  27. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  28. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  29. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  30. LIGO/Virgo/KAGRA S240422ed: Upper limits from a two-week IceCube neutrino search
  31. IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
  32. Fermi-LAT gamma-ray observations of IceCube-240424A
  33. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  34. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  35. IceCube Alert 240424.08: Global MASTER-Net observations report
  36. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  37. Fermi-LAT gamma-ray observations of IceCube-240419A
  38. IceCube Alert 240419.98: Global MASTER-Net observations report
  39. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  40. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  41. IceCube-Cascade 240416A: Upper limits from a search for additional neutrino events in IceCube
  42. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  43. Fermi-LAT gamma-ray observations of IceCube-240412A
  44. IceCube Alert 240412.23: Global MASTER-Net observations report
  45. IceCube-240412A - IceCube observation of a high-energy neutrino candidate track-like event
  46. IceCube-240327B: GRANDMA/Kilonova-Catcher observations of 4FGL J0555.9+0030 and optical upper limits
  47. Fermi-LAT gamma-ray observations of IceCube-240327B
  48. Fermi-LAT gamma-ray observations of IceCube-240327A
  49. IceCube-240327B: GRANDMA observations of 4FGL J0555.9+0030
  50. IceCube-240327B: Upper limits from a search for additional neutrino events in IceCube
  51. IceCube-240327A: Upper limits from a search for additional neutrino events in IceCube
  52. IceCube-240327B: No candidates from the Zwicky Transient Facility
  53. IceCube Alert 240327.68: Global MASTER-Net observations report
  54. IceCube-240327B - IceCube observation of a high-energy neutrino candidate track-like event
  55. IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
  56. Fermi-LAT gamma-ray observations of IceCube-240307A
  57. IceCube-240307A: Upper limits from a search for additional neutrino events in IceCube
  58. IceCube-240307A - IceCube observation of a high-energy neutrino candidate track-like event
  59. IceCube Alert 240307.32: Global MASTER-Net observations report
  60. Fermi-LAT gamma-ray observations of IceCube-240229A
  61. IceCube-240229A: Upper limits from a search for additional neutrino events in IceCube
  62. IceCube-240229A - IceCube observation of a high-energy neutrino candidate track-like event
  63. IceCube Alert 240229.66: Global MASTER-Net observations report
  64. Fermi-LAT gamma-ray observations of IceCube-240204A
  65. IceCube-240204A: Upper limits from a search for additional neutrino events in IceCube
  66. IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
  67. IceCube Alert 240204.38: Global MASTER-Net observations report
  68. IceCube-240123A: Upper limits from a search for additional neutrino events in IceCube
  69. Fermi-LAT gamma-ray observations of IceCube-240123A
  70. IceCube Alert 240123.48: Global MASTER-Net observations report
  71. IceCube-240123A - IceCube observation of a high-energy neutrino candidate track-like event
  72. IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER
  73. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A: correction on the localization
  74. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-240118A
  75. IceCube-240105A: ZTF optical observation of blazar PKS 0446+11
  76. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 0446+11, located inside the IceCube-240105A error region
  77. IceCube-240105A: Upper limits from a search for additional neutrino events in IceCube
  78. IceCube-240105A: Three candidates from the Zwicky Transient Facility
  79. IceCube-240105A: JCMT SCUBA2 Detection of Two Bright Submillimeter Sources
  80. Update of IceCube-240105A - Corrected errors
  81. IceCube Alert 240105.52: Global MASTER-Net observations report
  82. IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
  83. IceCube-Cascade 231230A: Upper limits from a search for additional neutrino events in IceCube
  84. IceCube-231211A: GRANDMA observations of PKS2047+098
  85. LIGO/Virgo/KAGRA S231215i: 3 counterpart neutrino candidate events from an IceCube neutrino search
  86. IceCube-231211A: Upper limits from a search for additional neutrino events in IceCube
  87. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  88. IceCube-231211A - IceCube observation of a high-energy neutrino candidate track-like event
  89. IceCube Alert 231211.03: Global MASTER-Net observations report
  90. IceCube-231202A: No candidates from the Zwicky Transient Facility
  91. Fermi-LAT gamma-ray observations of IceCube-231202A
  92. LIGO/Virgo/KAGRA S231205c: One counterpart neutrino candidate event from an IceCube neutrino search
  93. IceCube-231202A: Upper limits from a search for additional neutrino events in IceCube
  94. IceCube-231202A - IceCube observation of a high-energy neutrino candidate track-like event
  95. Fermi-LAT gamma-ray observations of IceCube-231125A
  96. IceCube-231125A: Upper limits from a search for additional neutrino events in IceCube
  97. Update of IceCube-231125A - Corrected errors
  98. IceCube-231125A - IceCube observation of a high-energy neutrino candidate track-like event
  99. LIGO/Virgo/KAGRA S231119u: One counterpart neutrino candidate from IceCube neutrino searches
  100. GRB 231115A: Upper limits from a neutrino search with IceCube

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