2005/07/20 by H. Awaki, Hisamitsu Awaki, H. Murakami +7
Physics and Astronomy · #Accretion (finance) #Active galactic nucleus #Adaptive optics and wavefront sensing #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black hole (networking) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Light curve #Luminosity #Physics #Power law #astro-ph
paper · pdf · doi:10.1086/433161
published as Astrophys.J.632:793-798,2005 · 11 pages, 6 figures, accepted for publication in ApJ
arxiv created 2005/07/20 · openalex publication_date 2005/10/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the results of timing analysis of the XMM-Newton observation of the Seyfert 2 galaxy NGC 6300. The hard X-ray spectrum above 2 keV consists of a Compton-thin absorbed power law, as is often seen in Seyfert 2 galaxies. We clearly detected rapid time variability on a timescale of about 1000 s from the light curve above 2 keV. The excess variance of the time variability (σ ) is calculated to be ~0.12, and the periodogram of the light curve is well represented by a power-law function with a slope of 1.75. In contrast to previous results from Seyfert 2 nuclei, these variability characteristics are consistent with those of Seyfert 1 galaxies. This consistency suggests that NGC 6300 has a black hole mass and accretion properties similar to Seyfert 1 galaxies. Using the relation between time variability and central black hole mass by Hayashida et al., the black hole mass of NGC 6300 is estimated to be ~2.8 × 10 5 M ☉ . Taking the uncertainty of this method into account, the black hole mass is less than 10 7 M ☉ . Taking the bolometric luminosity of 3.3 × 10 43 ergs s -1 into consideration, this yields an accretion rate of >0.03 of the Eddington value, comparable to estimates from Seyfert 1 galaxies using this method. The time variability analysis suggests that NGC 6300 actually has a Seyfert 1 nucleus obscured by thick matter and more generally provides a new pillar of support for the unified model of Seyfert galaxies based on obscuration.