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"

32482 results found.

  1. GRB 260827A: Glowbug gamma-ray detection
  2. EP260727a: ATCA 10 GHz detection
  3. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  4. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  5. GRB 260829A: GECAM-B observation of a long burst
  6. GRB 260825A: SVOM/GRM observation of a long burst
  7. GRB 260825A: GECAM-B observation
  8. GRB 260829A: Fermi GBM Detection
  9. GRB 260825A: AstroSat CZTI detection
  10. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  11. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  12. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  13. GRB 260818B: Further EP-FXT observation
  14. GRB 260818B: VLT optical and nIR observations
  15. GRB 260818B: TNG NIR observations
  16. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  17. GRB 260818B: 6 GHz VLA observations
  18. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  19. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  20. GRB 260808B: SAO RAS observations of the optical rebrightening
  21. EP260822a: Global MASTER-Net observations report
  22. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  23. GRB 260807A: EP-FXT follow-up observations
  24. GRB 260822A: SVOM/ECLAIRs refined analysis
  25. GRB 260809A: SVOM/ECLAIRs refined analysis
  26. GRB 260822A: SVOM/VT optical upper limits
  27. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  28. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  29. GRB 260822A: EP/FXT follow-up observations
  30. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  31. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  32. EP260822a: EP-FXT non-detection and upper limit
  33. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  34. GRB 260822A: GOTO optical counterpart detection
  35. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  36. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  37. GRB 260822A: LCO optical upper limits
  38. GRB 260822A: GROWTH-India Telescope Upper Limits
  39. GRB 260822A: GOTO optical upper limit
  40. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  41. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  42. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  43. GRB 260818B: VLA radio observations
  44. GRB 260818B: SVOM/C-GFT optical upper limit
  45. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  46. GRB 260820A: Insight-HXMT/HE detection
  47. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  48. GRB 260818B: SVOM/GRM observation
  49. GRB 260818B: Insight-HXMT detection
  50. GRB 260818B: EP-FXT follow-up observation
  51. GRB 260818A: J-band observations with WINTER
  52. GRB 260818B: SVOM/ECLAIRs refined analysis
  53. GRB 260818A: SVOM/ECLAIRs refined analysis
  54. GRB 260818B: NOT optical upper limits
  55. GRB 260810A: SVOM/GRM observation
  56. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  57. GRB260818A: EP-FXT follow-up observation
  58. GRB 260818B: LCO optical upper limits
  59. EP260806a: SAO RAS multicolor optical observations
  60. GRB 260818A: LCO optical upper limits
  61. EP260812a: AbAO optical upper limit
  62. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  63. GRB 260810A: Insight-HXMT/HE detection
  64. EP260806a: SVOM/ECLAIRs detection through targeted search
  65. EP260806a: NUTTELA-TAO optical observations
  66. EP260812a: AZT-22 optical upper limit
  67. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  68. EP260806a: WFST optical observations
  69. EP260812b: Optical upper limit with Kinder
  70. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  71. GRB 260808B: Liverpool Telescope further optical observations
  72. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  73. EP260812a: NOT and Liverpool Telescope upper limits:
  74. EP260812b: Liverpool Telescope observations
  75. EP260812b: GOTO detection of the optical counterpart
  76. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  77. EP260812a: SVOM/C-GFT optical upper limit
  78. EP260812b: COLIBRÍ optical observations
  79. EP260812b: SVOM/VT optical observation
  80. GRB 260808A: SVOM/GRM observation
  81. EP260812b: Einstein Probe detection of an X-ray transient
  82. Fermi GBM Sub-Threshold Detection of GRB 260809A
  83. GRB 260810A: Glowbug gamma-ray detection
  84. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  85. GRB 260809A: SAO RAS optical observations
  86. GRB 260808B: SAO RAS optical observations
  87. GRB 260808B: SVOM/VT optical re-brightening at day 3
  88. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  89. GRB 260806A: CALET Gamma-Ray Burst Monitor detection
  90. GRB 260808A: GECAM-B observation
  91. GRB 260807A: SVOM/ECLAIRs refined analysis
  92. EP260806a: MAO/AZT-22 optical observations
  93. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB260808B: MAO/AZT-22 optical observations
  95. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  96. GRB 260809A: J-band upper limit with WINTER
  97. EP260809a: VLT/X-shooter spectroscopic redshift z = 3.07
  98. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  99. GRB 260805C: CALET Gamma-Ray Burst Monitor detection
  100. GRB 260804A: CALET Gamma-Ray Burst Monitor detection

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov