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"

32494 results found.

  1. IceCube-260704A: No candidates from the Zwicky Transient Facility
  2. GRB 260706A: LCO optical upper limit
  3. GRB 260706A: EP-FXT follow-up observation
  4. GRB 260706A: Fermi GBM Observation
  5. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  6. IPN triangulation of GRB 260627A
  7. GRB 260705A: SVOM/ECLAIRs refined analysis
  8. GRB 260706A: SVOM detection of a burst
  9. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  10. IceCube260704A: OHP/T193 optical observations
  11. GRB 260705A: LCO optical upper limits
  12. GRB 260704A: NOT optical upper limits
  13. Fermi GBM Sub-Threshold Detection of GRB 260705A
  14. GRB 260704A: EP-FXT follow-up observation
  15. GRB 260629A: SVOM/GRM observation of a short burst
  16. GRB 260629A: GECAM-A observation of a short burst
  17. IceCube-260704A - IceCube observation of a high-energy neutrino candidate track-like event
  18. GRB 260629A: AstroSat CZTI detection
  19. EP260703a: EP-FXT follow-up observation
  20. Fermi GRB 260703A: Global MASTER-Net observations report
  21. GRB 260610B: VLA detection
  22. GRB 260623A: Glowbug gamma-ray detection
  23. GRB 260614B: ATCA Radio Upper Limits
  24. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  25. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  26. EP260628a: EP-FXT follow-up observation
  27. Fermi GRB 260628A: Global MASTER-Net observations report
  28. EP260626a: further Liverpool Telescope optical upper limits
  29. EP260626a: EP-FXT follow-up observation
  30. EP260626a: COLIBRÍ optical upper limit
  31. EP260626a: Liverpool Telescope upper limits
  32. Konus-Wind detection of GRB 260623B / EP260623a
  33. EP260623a: TNG NIR afterglow detection
  34. GRB 260618A: Fermi GBM Observation
  35. MASS-Cube (GRID 2.0) detection of GRB 260616B
  36. EP260623a: FTW optical and NIR observations
  37. GRB 260619A: SVOM/ECLAIRs refined analysis
  38. EP260623a: Liverpool Telescope optical observations
  39. Konus-Wind detection of GRB 260618B
  40. GRB 260624A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  41. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  42. EP260623a: WINTER J-band observations
  43. GRB 260617A: Glowbug gamma-ray detection of a short burst
  44. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  45. IPN triangulation of GRB 260605A
  46. EP260623a: Optical follow-up observations with Kinder
  47. EP260623a: FRAM-ORM detection of the optical afterglow rise, peak and decay
  48. EP260623a: SVOM/VT optical observations
  49. EP260623a: TRT optical observations
  50. EP260623a: REM optical/NIR afterglow detection
  51. EP 260623a: COLIBRÍ optical observations
  52. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  53. EP260623a: OSIRIS+/GTC redshift z = 0.703
  54. EP260623a: Las Cumbres discovery of the optical counterpart
  55. GRB 260614B: EP-FXT follow-up observation
  56. IceCube-260622A - IceCube observation of a high-energy neutrino candidate track-like event
  57. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  58. EP260618a: Liverpool Telescope optical observations
  59. GRB 260619A: NOT optical observations
  60. GRB 260618B: LCO optical observations
  61. EP260618a: JinShan optical observations
  62. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  63. GRB 260618B: Fermi GBM Observation
  64. GRB 260619A: TRT optical counterpart confirmation
  65. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  66. GRB 260604B: 239Alferov CubeSat detection
  67. GRB 260604A: 239Alferov CubeSat detection
  68. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  69. GRB 260619A: SVOM/VT optical counterpart confirmation
  70. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  71. GRB 260618B: SVOM/VT optical candidate
  72. GRB 260618B: SVOM/VT optical candidate (duplicate Submission of 45001)
  73. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  74. Konus-Wind detection of GRB 260617A
  75. GRB 260616B: AstroSat CZTI detection
  76. GRB 260616A: AstroSat CZTI detection
  77. GRB 260616A: SVOM/GRM observation
  78. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  79. GRB 260619A: Kilonova-Catcher optical upper limit
  80. EP260618a: EP-FXT follow-up observation
  81. EP260618a: LCO optical counterpart confirmation
  82. GRB 260617A: CALET Gamma-Ray Burst Monitor detection
  83. EP260618a: COLIBRÍ optical counterpart candidate
  84. GRB 260616A: NuSTAR detection of prompt emission
  85. GRB 260614B: NuSTAR detection of prompt emission
  86. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  87. GRB 260618B: Fermi-LAT detection
  88. IPN triangulation of GRB 260617A (short)
  89. GRB 260610B/AT 2026owq: FTW optical and NIR observations
  90. GRB 260616A: Insight-HXMT detection
  91. EP260618a: EP-WXT detection of an X-ray transient
  92. GRB 260610B: AbAO optical observations
  93. EP260616a/GRB 260616B: EP-FXT follow-up observation
  94. GRB 260506B: cubesat Avion detection
  95. GRB 260616C: GECAM-B observation of a burst
  96. GRB 260616A: Fermi GBM Observation
  97. GRB 260617A: Fermi GBM Final Real-time Localization (Duplicate Submission)
  98. Konus-Wind detection of GRB 260616B/EP260616a
  99. Konus-Wind detection of GRB 260616A
  100. GRB 260616B: 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