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"

28048 results found.

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

Advanced

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