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"

26500 results found.

  1. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  2. GRB 260619A: TRT optical counterpart confirmation
  3. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  4. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  5. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  6. Konus-Wind detection of GRB 260617A
  7. GRB 260616B: AstroSat CZTI detection
  8. GRB 260616A: AstroSat CZTI detection
  9. GRB 260616A: SVOM/GRM observation
  10. EP260618a: OHP/T193 optical observations
  11. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  12. GRB 260619A: Kilonova-Catcher optical upper limit
  13. EP260618a: EP-FXT follow-up observation
  14. EP260618a: LCO optical counterpart confirmation
  15. EP260618a: COLIBRÍ optical counterpart candidate
  16. GRB 260619A: SVOM possible detection of a faint burst
  17. IceCube-260610A: Upper limits from a search for additional neutrino events in IceCube
  18. EP260618a: EP-WXT detection of an X-ray transient
  19. GRB 260610B: AbAO optical observations
  20. EP260616a/GRB 260616B: EP-FXT follow-up observation
  21. GRB 260506B: cubesat Avion detection
  22. GRB 260616C: GECAM-B observation of a burst
  23. GRB 260617A: Fermi GBM Detection
  24. GRB 260616A: Fermi GBM Observation
  25. Konus-Wind detection of GRB 260616B/EP260616a
  26. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  27. GRB 260616A: GECAM-B observation
  28. GRB 260610B / AT2026owq: SAO RAS optical observations of possible re-brightening
  29. GRB 260429A: cubesat Avion detection
  30. GRB 260610B / AT 2026owq: COLIBRÍ further observations and confirmation of the rebrigthening
  31. EP260616a: EP-WXT detection of a fast X-ray transient
  32. The EP-WXT trigger 01709270148 is likely a flaring star
  33. GRB 260616B: Fermi GBM Detection
  34. The EP-WXT trigger 01709269893 is likely a flaring star
  35. GRB 260614B: SVOM/ECLAIRs refined analysis
  36. GRB 260610B: Terskol optical observations
  37. GRB 260614B: GECAM-B observation
  38. GRB 260610B: SVOM/GRM observation
  39. GRB 260614B: Fermi GBM Observation
  40. GRB 260614B: SVOM/VT optical candidate from VHF data
  41. GRB 260614B: SVOM detection of a burst
  42. GRB 260611B: SVOM/GRM detection
  43. The EP-WXT trigger 01709269488 is likely a flaring star
  44. GRB 260603C: AstroSat CZTI detection
  45. GRB 260610B: further Liverpool Telescope optical observations
  46. GRB 260610B: Fermi GBM Observation
  47. GRB 260610B / AT2026owq: GRANDMA optical observations
  48. GRB 260610B / AT2026owq: further SAO RAS optical observations
  49. EP260605a: COLIBRÍ optical upper limits
  50. GRB 260610b: Liverpool Telescope optical observations
  51. EP260610b: Liverpool Telescope optical upper limits
  52. IceCube-260610A: EP-FXT follow-up observation
  53. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  54. GRB 260610B / AT2026owq: SAO RAS optical observations
  55. The EP-WXT trigger 01709269176 is likely a flaring star
  56. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  57. GRB 260610B / AT 2026owq: COLIBRÍ optical observations
  58. GRB 260610B: TRT optical observation
  59. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  60. EP260610b: COLIBRÍ optical observations
  61. GRB 260610B: DDOTI optical observations
  62. EP260610b: MAO/AZT-22 optical observations
  63. EP260610b: NOT optical observation
  64. EP260610b: SVOM/VT optical confirmation with blue color
  65. GRB 260515A: SOAR optical observations
  66. EP260610a: SVOM/VT optical upper limits
  67. EP260610b: Einstein Probe detection of an X-ray transient
  68. Konus-Wind detection of GRB 260601A
  69. EP260610a: COLIBRÍ optical upper limits
  70. EP260610a: Einstein Probe detection of a fast X-ray transient
  71. GRB 260608A: Fermi GRB Observation
  72. GRB 260604C: SVOM/ECLAIRs refined analysis
  73. GRB 260608A: SVOM/ECLAIRs refined analysis
  74. GRB 260607B: GECAM-B observation
  75. GRB 260604C: further SAO RAS optical observations
  76. GRB 260607A: AT2026ong (GOTO26fqf) is a type-Ia SN
  77. GRB 260607A / GOTO26fqf / AT2026ong: COLIBRÍ optical observations
  78. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) colour evolution and confirmation of the late rebrightening
  79. GRB 260604C: SVOM/C-GFT upper limit
  80. GRB 260607B: AstroSat CZTI detection
  81. GRB 260608A: SVOM detection of a burst
  82. EP260605a: EP-FXT follow-up observation
  83. GRB 260607A: TRT optical observations
  84. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  85. GRB 260604A: SVOM/GRM detection
  86. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  87. GRB 260607B: Fermi GBM Observation
  88. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  89. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  90. GRB 260604C: GECAM-B observation
  91. GRB 260604C: 6 GHz VLA observations
  92. GRB 260604C: SAO RAS optical observations
  93. GRB 260604B: SVOM/GRM detection
  94. GRB260603A: SVOM/ECLAIRs refined analysis
  95. EP260605a: Einstein Probe detection of a fast X-ray transient
  96. EP260603a: COLIBRÍ optical upper limit
  97. GRB 260604A: Glowbug gamma-ray detection
  98. GRB 260604C: LCO optical upper limit
  99. The EP-WXT trigger 01709267001 is likely a flaring star
  100. EP260602d: EP-FXT follow-up observation

Advanced

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