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"

27731 results found.

  1. GRB 260619A: SVOM/VT continuous optical observations
  2. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  3. EP260623a: KAIT optical observations
  4. GRB 260708A: GRANDMA Optical Observations
  5. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  6. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  7. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  8. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  9. GRB 260708A: LCO optical observations
  10. EP260711a: Einstein Probe detection of an X-ray transient
  11. GRB 260709A: SVOM/GRM detection
  12. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  13. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  14. GRB 260708A: Glowbug gamma-ray detection
  15. GRB 260706A : GRANDMA Upper limits
  16. GRB 260708A: Kilonova-Catcher optical afterglow detection
  17. IceCube-260708A: One candidate from the Zwicky Transient Facility
  18. GRB 260708A: Fermi-GBM observation
  19. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  20. IceCube Alert 260709A: Global MASTER-Net observations report
  21. LAT GRB260708.42: Global MASTER-Net observations report
  22. GRB260708B: MAXI/GSC detection
  23. GRB 260705B: SVOM/GRM observation
  24. GRB 260706A: Further EP-FXT follow-up observation
  25. EP260707a (by EP-FXT): NOT optical upper limit
  26. EP260707a is not a real source
  27. EP260707a: LCOGT Optical Upper Limit
  28. EP260707a: TRT optical upper limit
  29. EP260707a: Einstein Probe detection of an X-ray transient
  30. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  31. GRB 260705C: Glowbug gamma-ray detection of a short burst
  32. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  33. GRB 260706A: REM optical/NIR observations
  34. GRB 260706A: LCO optical upper limit
  35. GRB 260706A: EP-FXT follow-up observation
  36. The EP-WXT trigger 01709274151 is likely a flaring star
  37. GRB 260706A: Fermi GBM Observation
  38. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  39. GRB 260706A: SVOM detection of a burst
  40. GRB 260705A: LCO optical upper limits
  41. GRB 260704A: NOT optical upper limits
  42. Fermi GBM Sub-Threshold Detection of GRB 260705A
  43. GRB 260704A: EP-FXT follow-up observation
  44. GRB 260629A: SVOM/GRM observation of a short burst
  45. GRB 260629A: AstroSat CZTI detection
  46. EP260703a: EP-FXT follow-up observation
  47. GRB 260704A: SVOM detection of a possible GRB
  48. EP260703a: EP-WXT detection of a fast X-ray transient
  49. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  50. Fermi trigger No 804738310: Global MASTER-Net observations report
  51. Fermi GRB 260703A: Global MASTER-Net observations report
  52. GRB 260623A: Glowbug gamma-ray detection
  53. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  54. Fermi trigger No 804552016: Global MASTER-Net observations report
  55. GRB 260701A: Fermi GBM Final Real-time Localization
  56. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  57. EP260628a: EP-FXT follow-up observation
  58. Fermi GRB 260628A: Global MASTER-Net observations report
  59. EP260628a: EP-WXT detection of a fast X-ray transient
  60. EP260626a: further Liverpool Telescope optical upper limits
  61. EP260626a: COLIBRÍ optical upper limit
  62. EP260626a: Liverpool Telescope upper limits
  63. EP260626a: EP-WXT detection of a fast X-ray transient
  64. EP260623a: TNG NIR afterglow detection
  65. GRB 260618A: Fermi GBM Observation
  66. GRB 260619A: SVOM/ECLAIRs refined analysis
  67. EP260623a: Liverpool Telescope optical observations
  68. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  69. EP260623a: WINTER J-band observations
  70. GRB 260617A: Glowbug gamma-ray detection of a short burst
  71. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  72. EP260623a: Optical follow-up observations with Kinder
  73. EP260623a: SVOM/VT optical observations
  74. EP260623a: TRT optical observations
  75. EP260623a: REM optical/NIR afterglow detection
  76. EP 260623a: COLIBRÍ optical observations
  77. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  78. EP260623a: Las Cumbres discovery of the optical counterpart
  79. EP260623a: Einstein Probe detection of an X-ray transient
  80. GRB 260614B: EP-FXT follow-up observation
  81. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  82. EP260618a: Liverpool Telescope optical observations
  83. GRB 260618B: LCO optical observations
  84. EP260618a: JinShan optical observations
  85. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  86. GRB 260618B: Fermi GBM Observation
  87. IceCube-Cascade 260618A: Upper limits from a search for additional neutrino events in IceCube
  88. GRB 260619A: TRT optical counterpart confirmation
  89. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  90. Fermi-LAT Gamma-ray Observations of IceCube-260610A
  91. GRB 260619A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  92. GRB 260616B: AstroSat CZTI detection
  93. GRB 260616A: AstroSat CZTI detection
  94. GRB 260616A: SVOM/GRM observation
  95. EP260618a: OHP/T193 optical observations
  96. GRB 260610B/AT2026owq: 1.3m DFOT optical rebrightening detection
  97. GRB 260619A: Kilonova-Catcher optical upper limit
  98. EP260618a: LCO optical counterpart confirmation
  99. EP260618a: COLIBRÍ optical counterpart candidate
  100. GRB 260616A: NuSTAR detection of prompt emission

Advanced

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