We report the detection of a 5.8 × 104 s (∼ 16 hr) periodicity in the 0.5-10 keV X-ray light curve of the Seyfert galaxy IRAS18325-5926, obtained from a 5-day ASCA observation. Nearly 9 cycles of the periodic variation are seen; it shows no strong energy dependence and has an amplitude of about 15 per cent. Unlike most other well-studied Seyfert galaxies, there is no evidence for strong power-law red noise in the X-ray power spectrum of IRAS18325-5926. Scaling from the QPOs found in Galactic black hole candidates suggests that the mass of the black hole in IRAS18325-5926 is ∼ 107M⊙.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics