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"

38349 results found.

  1. GRB 260909A: SVOM/GRM observation
  2. GRB 260909A: Mondy optical observations and afterglow candidate
  3. GRB 260909A: Xinglong 2.16m optical upper limit
  4. GRB 260909A: SVOM/C-GFT optical upper limit
  5. GRB 260909A: SVOM detection of a burst
  6. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  7. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  8. GRB 260903A: Swift ToO observations
  9. GRB 260903A: SAO RAS optical upper limit
  10. The EP-WXT trigger 01709305715 is likely a flaring star
  11. GRB 260907B: Fermi GBM Final Real-time Localization
  12. GRB 260907A: Fermi GBM Final Real-time Localization
  13. EP260903a: EP-FXT follow-up observation
  14. The EP-WXT trigger 01709302592 is likely a flaring star
  15. GRB 260903A: J-band upper limit with WINTER
  16. GRB 260903A: SVOM/ECLAIRs refined analysis
  17. GRB260903A: Liverpool Telescope optical observations
  18. GRB 260903A: SAO RAS optical observations
  19. GRB 260830A: GECAM-B detection of a burst
  20. EP260903a: EP-WXT detection of a fast X-ray transient
  21. GRB 260830A: Insight-HXMT/HE detection
  22. GRB 260903A: EP-FXT follow-up observation
  23. GRB 260903A: OHP/T193 optical afterglow detection
  24. GRB 260903A: NOT optical observations and afterglow fading
  25. NuSTAR Transient 260828: SOAR Optical Upper Limits
  26. SVOM GRB260903A: Global MASTER-Net observations report
  27. GRB 260903A: LCO optical observations
  28. GRB 260903A: SVOM/VT optical candidate
  29. GRB 260903A: Retraction of optical counterpart of GCN 45501
  30. GRB 260831A: GECAM-B observation
  31. GRB 260903A: LCO optical counterpart detection
  32. GRB 260827A: Insight-HXMT/HE detection
  33. GRB 260903A: SVOM detection of a soft faint burst
  34. EP260901a: SVOM/VT optical upper limits
  35. EP260901a: EP-FXT follow-up observation
  36. Konus-Wind detection of GRB 260829A
  37. GRB 260829A: SVOM/GRM observation
  38. GRB 260818A: ATCA detection of a candidate radio counterpart
  39. EP260830a: EP-FXT follow-up observation
  40. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  41. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  42. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  43. NuSTAR Transient 260828: LCO Optical Upper Limits
  44. EP260901a: EP-WXT detection of a fast X-ray transient
  45. SVOM trigger sb26083106 is not a GRB
  46. GRB 260829A: AstroSat CZTI detection
  47. GRB 260831B: EP-FXT follow-up observation
  48. GRB 260830A: NuSTAR detection of prompt emission
  49. GRB 260831B: LCO optical upper limits
  50. EP260830a: EP-WXT detection of a fast X-ray transient
  51. GRB 260827A: SVOM/GRM observation
  52. NuSTAR 260828: a 1100s hard X-ray transient
  53. GRB 260831B: SVOM detection of a possible burst
  54. IPN triangulation of GRB 260829A
  55. GRB 260827A: Glowbug gamma-ray detection
  56. EP260727a: ATCA 10 GHz detection
  57. GRB 260831A: Fermi GBM Final Real-time Localization
  58. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  59. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  60. GRB 260829A: GECAM-B observation of a long burst
  61. GRB 260825A: SVOM/GRM observation of a long burst
  62. GRB 260825A: GECAM-B observation
  63. GRB 260829A: Fermi GBM Detection
  64. GRB 260825A: AstroSat CZTI detection
  65. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  66. GRB 260829A: Fermi GBM Final Real-time Localization
  67. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  68. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  69. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  70. Fermi GBM trigger 809666623/260829141 is not a GRB
  71. GRB 260818B: Further EP-FXT observation
  72. GRB 260818B: VLT optical and nIR observations
  73. GRB 260818B: TNG NIR observations
  74. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  75. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  76. GRB 260827A: Fermi GBM Final Real-time Localization
  77. GRB 260818B: 6 GHz VLA observations
  78. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  79. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  80. GRB 260808B: SAO RAS observations of the optical rebrightening
  81. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  82. GRB 260807A: EP-FXT follow-up observations
  83. GRB 260822A: SVOM/ECLAIRs refined analysis
  84. GRB 260809A: SVOM/ECLAIRs refined analysis
  85. GRB 260822A: SVOM/VT optical upper limits
  86. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  87. GRB 260825A: Fermi GBM Final Real-time Localization
  88. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  89. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  90. GRB 260822A: EP/FXT follow-up observations
  91. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  92. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  93. EP260822a: EP-FXT non-detection and upper limit
  94. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  95. GRB 260822A: GOTO optical counterpart detection
  96. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  97. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  98. EP260822a: Einstein Probe detection of a fast X-ray transient
  99. GRB 260822A: LCO optical upper limits
  100. The EP-WXT trigger 01709287395 is likely a flaring star

Advanced

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