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"

39152 results found.

  1. GRB 260831A: GECAM-B observation
  2. GRB 260903A: LCO optical counterpart detection
  3. GRB 260827A: Insight-HXMT/HE detection
  4. GRB 260903A: SVOM detection of a soft faint burst
  5. Konus-Wind detection of GRB 260829A
  6. GRB 260829A: SVOM/GRM observation
  7. GRB 260818A: ATCA detection of a candidate radio counterpart
  8. EP260901a: Global MASTER-Net observations report
  9. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  10. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  11. NuSTAR Transient 260828: LCO Optical Upper Limits
  12. SVOM trigger sb26083106 is not a GRB
  13. GRB 260829A: AstroSat CZTI detection
  14. GRB 260831B: EP-FXT follow-up observation
  15. GRB 260830A: NuSTAR detection of prompt emission
  16. GRB 260831B: LCO optical upper limits
  17. EP260830a: Global MASTER-Net observations report
  18. GRB 260827A: SVOM/GRM observation
  19. GRB 260831B: SVOM detection of a possible burst
  20. IPN triangulation of GRB 260829A
  21. GRB 260827A: Glowbug gamma-ray detection
  22. GRB 260831A: Fermi GBM Final Real-time Localization
  23. GRB 260829A: GECAM-B observation of a long burst
  24. GRB 260825A: SVOM/GRM observation of a long burst
  25. GRB 260825A: GECAM-B observation
  26. GRB 260829A: Fermi GBM Detection
  27. GRB 260825A: AstroSat CZTI detection
  28. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  29. GRB 260829A: Fermi GBM Final Real-time Localization
  30. Fermi GBM trigger 809666623/260829141 is not a GRB
  31. GRB 260818B: Further EP-FXT observation
  32. GRB 260818B: VLT optical and nIR observations
  33. GRB 260818B: TNG NIR observations
  34. MAXI GRB260827.40: Global MASTER-Net observations report
  35. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  36. GRB 260827A: Fermi GBM Final Real-time Localization
  37. GRB 260818B: 6 GHz VLA observations
  38. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  39. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  40. GRB 260808B: SAO RAS observations of the optical rebrightening
  41. EP260822a: Global MASTER-Net observations report
  42. EP Alert 260820.31: Global MASTER-Net observations report
  43. GRB 260807A: EP-FXT follow-up observations
  44. GRB 260822A: SVOM/ECLAIRs refined analysis
  45. GRB 260809A: SVOM/ECLAIRs refined analysis
  46. GRB 260822A: SVOM/VT optical upper limits
  47. IceCube Alert 260825A: Global MASTER-Net observations report
  48. GRB 260825A: Fermi GBM Final Real-time Localization
  49. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  50. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  51. GRB 260822A: EP/FXT follow-up observations
  52. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  53. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  54. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  55. GRB 260822A: GOTO optical counterpart detection
  56. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  57. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  58. EP260822a: Einstein Probe detection of a fast X-ray transient
  59. GRB 260822A: LCO optical upper limits
  60. The EP-WXT trigger 01709287395 is likely a flaring star
  61. GRB260822B: Fermi GBM Final Localization
  62. GRB 260822A: GROWTH-India Telescope Upper Limits
  63. GRB 260822A: GOTO optical upper limit
  64. GRB 260822A: SVOM detection of a short burst
  65. GRB 260818B: VLA radio observations
  66. GRB 260818B: SVOM/C-GFT optical upper limit
  67. IceCube Alert 260821A: Global MASTER-Net observations report
  68. GRB 260820A: Insight-HXMT/HE detection
  69. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  70. GRB 260818B: SVOM/GRM observation
  71. GRB260820A: Fermi GBM Final Real-Time Localization
  72. GRB 260818B: Insight-HXMT detection
  73. GRB 260818B: EP-FXT follow-up observation
  74. GRB 260818A: J-band observations with WINTER
  75. GRB 260818B: SVOM/ECLAIRs refined analysis
  76. GRB 260818A: SVOM/ECLAIRs refined analysis
  77. GRB 260818B: NOT optical upper limits
  78. GRB 260810A: SVOM/GRM observation
  79. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  80. GRB260818A: EP-FXT follow-up observation
  81. GRB 260818B: LCO optical upper limits
  82. GRB 260818B: SVOM detection of a short burst
  83. SVOM trigger sb26081806 is not a GRB
  84. EP260806a: SAO RAS multicolor optical observations
  85. GRB 260818A: LCO optical upper limits
  86. EP260812a: AbAO optical upper limit
  87. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  88. GRB 260810A: Insight-HXMT/HE detection
  89. GRB 260818A: SVOM possible detection of a long and faint GRB
  90. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  91. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  92. GRB 260808B: Liverpool Telescope further optical observations
  93. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  94. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  95. GRB 260813A: Fermi GBM Final Real-time Localization
  96. EP260812a: NOT and Liverpool Telescope upper limits:
  97. EP260812a: SVOM/C-GFT optical upper limit
  98. EP260812b: COLIBRÍ optical observations
  99. GRB 260808A: SVOM/GRM observation
  100. Fermi GBM Sub-Threshold Detection of GRB 260809A

Advanced

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