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Detection of an X-ray periodicity in the Seyfert galaxy IRAS18325-5926

K. Iwasawa·A. C. Fabian·W. N. Brandt·H. Kunieda·K. Misaki·C. S. Reynolds·Y. Terashima
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Abstract

We report the detection of a 58 ks (16 hr) periodicity in the 0.5-10 keV X-ray light curve of the Seyfert galaxy IRAS18325-5926 (Fairall49), 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 (6-40) million solar masses.

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K. Iwasawa, A. C. Fabian, W. N. Brandt, H. Kunieda, K. Misaki, C. S. Reynolds, Y. Terashima. 1998-01-23. Detection of an X-ray periodicity in the Seyfert galaxy IRAS18325-5926. https://doi.org/10.1046/j.1365-8711.1998.29511476.x

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