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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"

1520 results found.

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

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