Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

1526 results found.

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

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov