Disentangling AGN and Star Formation in Soft X-rays

Abstract

We have explored the interplay of star formation and AGN activity in soft X-rays (0.5-2 keV) in two samples of Seyfert 2 galaxies (Sy2s). Using a combination of low resolution CCD spectra from Chandra and XMM-Newton, we modeled the soft emission of 34 Sy2s using power law and thermal models. For the 11 sources with high signal-to-noise Chandra imaging of the diffuse host galaxy emission, we estimate the luminosity due to star formation by removing the AGN, fitting the residual emission. The AGN and star formation contributions to the soft X-ray luminosity (i.e. L${}_{x,AGN}$ and L${}_{x,SF}$) for the remaining 24 Sy2s were estimated from the power law and thermal luminosities derived from spectral fitting. These luminosities were scaled based on a template derived from XSINGS analysis of normal star forming galaxies. To account for errors in the luminosities derived from spectral fitting and the spread in the scaling factor, we estimated L${}_{x,AGN}$ and L${}_{x,SF}$ from Monte Carlo simulations. These simulated luminosities agree with L${}_{x,AGN}$ and L${}_{x,SF}$ derived from Chandra imaging analysis within a 3σ confidence level. Using the infrared [NeII]12.8μm and [OIV]26μm lines as a proxy of star formation and AGN activity, respectively, we independently disentangle the contributions of these two processes to the total soft X-ray emission. This decomposition generally agrees with L${}_{x,SF}$ and L${}_{x,AGN}$ at the 3σ level. In the absence of resolvable nuclear emission, our decomposition method provides a reasonable estimate of emission due to star formation in galaxies hosting type 2 AGN.

accepted for publication in ApJ; 34 pages, 9 tables, 4 figures

References in corpus (10)

• The Host Galaxies and Classification of Active Galactic Nuclei
• A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies: I. Galaxy Mergers & Quasar Activity
• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• The bulk of the black hole growth since z~1 occurs in a secular universe: No major merger-AGN connection
• HST WFC3/IR Observations of Active Galactic Nucleus Host Galaxies at z~2: Supermassive Black Holes Grow in Disk Galaxies
• New Indicators for AGN Power: The Correlation Between [O IV] lambda 25.89 micron and Hard X-ray Luminosity for Nearby Seyfert Galaxies
• Spitzer IRS spectra of a large sample of Seyfert galaxies: a variety of infrared SEDs in the local AGN population
• The Mid-infrared Fine-structure Lines of Neon as an Indicator of Star For mation Rate in Galaxies
• Calibration of [O IV] 26 micron as a Measure of Intrinsic AGN Luminosity
• Exploring the Connection Between Star Formation and AGN Activity in the Local Universe

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