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"

28047 results found.

  1. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  2. GRB 260714B: COLIBRÍ optical counterpart candidate
  3. SVOM sb26071506: Global MASTER-Net observations report
  4. sb26071506: SVOM detection of a X-ray transient
  5. EP260703a: SVOM/ECLAIRs Upper Limit
  6. GRB 260710A: AstroSat CZTI detection
  7. GRB 260714B: Fermi GBM Detection
  8. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  9. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  10. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  11. EP260713a: Einstein Probe detection of an X-ray transient
  12. GRB 260619A: SVOM/VT continuous optical observations
  13. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  14. EP260623a: KAIT optical observations
  15. GRB 260708A: GRANDMA Optical Observations
  16. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  17. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  18. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  19. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  20. GRB 260708A: LCO optical observations
  21. EP260711a: Einstein Probe detection of an X-ray transient
  22. GRB 260709A: SVOM/GRM detection
  23. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  24. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  25. GRB 260708A: Glowbug gamma-ray detection
  26. GRB 260706A : GRANDMA Upper limits
  27. GRB 260708A: Kilonova-Catcher optical afterglow detection
  28. IceCube-260708A: One candidate from the Zwicky Transient Facility
  29. GRB 260708A: Fermi-GBM observation
  30. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  31. IceCube Alert 260709A: Global MASTER-Net observations report
  32. LAT GRB260708.42: Global MASTER-Net observations report
  33. GRB260708B: MAXI/GSC detection
  34. GRB 260705B: SVOM/GRM observation
  35. GRB 260706A: Further EP-FXT follow-up observation
  36. EP260707a (by EP-FXT): NOT optical upper limit
  37. EP260707a is not a real source
  38. EP260707a: LCOGT Optical Upper Limit
  39. EP260707a: TRT optical upper limit
  40. EP260707a: Einstein Probe detection of an X-ray transient
  41. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  42. GRB 260705C: Glowbug gamma-ray detection of a short burst
  43. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  44. GRB 260706A: REM optical/NIR observations
  45. GRB 260706A: LCO optical upper limit
  46. GRB 260706A: EP-FXT follow-up observation
  47. The EP-WXT trigger 01709274151 is likely a flaring star
  48. GRB 260706A: Fermi GBM Observation
  49. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  50. GRB 260706A: SVOM detection of a burst
  51. GRB 260705A: LCO optical upper limits
  52. GRB 260704A: NOT optical upper limits
  53. Fermi GBM Sub-Threshold Detection of GRB 260705A
  54. GRB 260704A: EP-FXT follow-up observation
  55. GRB 260629A: SVOM/GRM observation of a short burst
  56. GRB 260629A: AstroSat CZTI detection
  57. EP260703a: EP-FXT follow-up observation
  58. GRB 260704A: SVOM detection of a possible GRB
  59. EP260703a: EP-WXT detection of a fast X-ray transient
  60. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  61. Fermi trigger No 804738310: Global MASTER-Net observations report
  62. Fermi GRB 260703A: Global MASTER-Net observations report
  63. GRB 260623A: Glowbug gamma-ray detection
  64. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  65. Fermi trigger No 804552016: Global MASTER-Net observations report
  66. GRB 260701A: Fermi GBM Final Real-time Localization
  67. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  68. EP260628a: EP-FXT follow-up observation
  69. Fermi GRB 260628A: Global MASTER-Net observations report
  70. EP260628a: EP-WXT detection of a fast X-ray transient
  71. EP260626a: further Liverpool Telescope optical upper limits
  72. EP260626a: COLIBRÍ optical upper limit
  73. EP260626a: Liverpool Telescope upper limits
  74. EP260626a: EP-WXT detection of a fast X-ray transient
  75. EP260623a: TNG NIR afterglow detection
  76. GRB 260618A: Fermi GBM Observation
  77. GRB 260619A: SVOM/ECLAIRs refined analysis
  78. EP260623a: Liverpool Telescope optical observations
  79. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  80. EP260623a: WINTER J-band observations
  81. GRB 260617A: Glowbug gamma-ray detection of a short burst
  82. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  83. EP260623a: Optical follow-up observations with Kinder
  84. EP260623a: SVOM/VT optical observations
  85. EP260623a: TRT optical observations
  86. EP260623a: REM optical/NIR afterglow detection
  87. EP 260623a: COLIBRÍ optical observations
  88. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  89. EP260623a: Las Cumbres discovery of the optical counterpart
  90. EP260623a: Einstein Probe detection of an X-ray transient
  91. GRB 260614B: EP-FXT follow-up observation
  92. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  93. EP260618a: Liverpool Telescope optical observations
  94. GRB 260618B: LCO optical observations
  95. EP260618a: JinShan optical observations
  96. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  97. GRB 260618B: Fermi GBM Observation
  98. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  99. GRB 260619A: TRT optical counterpart confirmation
  100. GRB 260610B: Further GRANDMA Optical Observations and re-brightening 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