An XMM–Newton spectral survey of 12 μm selected galaxies – I. X-ray data

By M. Brightman, K. Nandra. 2010

263 citations recorded by the source corpus.

We present an X-ray spectral analysis of 126 galaxies of the 12 μm galaxy sample. By studying this sample at X-ray wavelengths, we aim to determine the intrinsic power, continuum shape and obscuration level in these sources. We improve upon previous works by the use of superior data in the form of higher signal-to-noise ratio spectra, finer spectral resolution and a broader bandpass from XMM–Newton. We pay particular attention to Compton thick active galactic nucleus (AGN) with the help of new spectral fitting models that we have produced, which are based on Monte Carlo simulations of X-ray radiative transfer, using both a spherical and torus geometry, and taking into account Compton scattering and iron fluorescence. We use this data to show that with a torus geometry, unobscured sightlines can achieve a maximum equivalent width of the Fe Kα line of ∼150 eV, originally shown by Ghisellini et al. In order for this to be exceeded, the line of sight must be obscured with NH > 10 23 cm −2 , as we show for one case, NGC 3690. We also calculate flux suppression factors from the simulated data, the main conclusion from which is that for NH ≥ 10 25 cm −2 , the X-ray flux is suppressed by a factor of at least 10 in all X-ray bands and at all redshifts, revealing the biases present against these extremely heavily obscured systems inherent in all X-ray surveys. Furthermore, we confirm previous results from Murphy & Yaqoob that show that the reflection fraction determined from slab geometries is underestimated with respect to toroidal geometries. For the 12 μm selected galaxies, we investigate the distribution of X-ray power-law indices, finding that the mean (� � �= 1.90 +0.05 −0.07 and σ � = 0.31 +0.05 −0.05 ) is consistent with previous works, and that the distribution = = = =

Subfields: Astronomy and Astrophysics, Radiation

View Paper: https://www.semanticscholar.org/paper/a156cb66055ec00e29cb5687c1d348673e809766

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In Astronomy and Astrophysics

1. D. M. Alexander
2. W. N. Brandt
3. H. Netzer
4. P. Hopkins
5. L. Hernquist
6. Mara Salvato
7. R. Hickox
8. A. Merloni

In Radiation

1. T. Yaqoob
2. H. Netzer
3. C. Ricci
4. Y. Ueda
5. Poshak Gandhi
6. M. Brightman
7. R. Nikutta
8. A. Markowitz

Citations in the corpus

• X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue (2014, methodology): “In the faceon view, the Compton scattering off the torus is part of the model spectrum (see Brightman & Nandra 2011).”
• OBSCURATION-DEPENDENT EVOLUTION OF ACTIVE GALACTIC NUCLEI (2015, methodology): “…modified by photoelectric absorption and Compton scattering from 6 Buchner et al. an obscurer with toroidal geometry simulated by the torus model of Brightman & Nandra (2011a), 2. a Compton-reflection component approximated by the pexmon model (Nandra et al. 2007) and 3. a soft scattering…”
• A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys (2013, methodology): “…luminosity (LX) have reported a positive correlation between these quantities in high-redshift sources (Dai et al. 2004; Saez et al. 2008), but not seen in the local universe (George et al. 2000; Brightman & Nandra 2011), and an evolution of this correlation was also reported in Saez et al. (2008).”
• COMPTON-THICK ACCRETION IN THE LOCAL UNIVERSE (2015, methodology): “In order to better constrain the column density and intrinsic flux, AGNs with NH consistent with 10 cm24 2 - within their 90% uncertainties were then fitted with the physical torus model of Brightman & Nandra (2011), which considers absorption and reflection for a spherical–toroidal geometry.”
• New Spectral Model for Constraining Torus Covering Factors from Broadband X-Ray Spectra of Active Galactic Nuclei (2018, methodology): “A comparison with the BNtorus model (Brightman & Nandra 2011), which shares the geometry chosen for borus02, but is less flexible and does not reproduce reprocessed spectra correctly, is given in § 2.3.”
• BAT AGN Spectroscopic Survey. V. X-Ray Properties of the Swift/BAT 70-month AGN Catalog (2017, methodology): “The table lists, for the objects with log(NH/cm −2) within their 90% confidence intervals, the (1) sources for which the torus model of Brightman & Nandra (2011) was applied: (2) the half-opening angle of the torus, (3) the column density, (4) the photon index, (5) the fraction of scattered…”
• Growing supermassive black holes in the late stages of galaxy mergers are heavily obscured (2017, methodology): “In order to self-consistently reproduce absorbed and reprocessed X-ray radiation from the circumnuclear material of the AGN we used the torus model developed by Brightman & Nandra (2011), which considers an Xray source surrounded by a spherical-toroidal structure c© 2017 RAS, MNRAS 000, 1–??”
• First X-ray-based statistical tests for clumpy-torus models: eclipse events from 230 years of monitoring of Seyfert AGN (2014, methodology): “References for typical values of Γ and NH are: B11 = Brightman & Nandra (2011); E06 = Evans et al. (2006); G09 = González-Mart́ın et al. (2009); R11 = Rivers et al. (2011a); R13 = Rivers et al. (2013); R02 = Risaliti, Elvis & Nicastro (2002) and references therein; TW = this work (Mkn 348: average ”
• The nature of the Compton-thick X-ray reprocessor in NGC 4945 (2012, methodology): “We have also applied the toroidal and spherical models of Brightman and Nandra (2011) to these data.”
• Revisiting the Unified Model of Active Galactic Nuclei (2015, methodology): “In the local Universe, such objects represent about 30% of all type-II objects (Panessa & Bassani 2002, Tran 2003, Shi et al. 2010, Brightman & Nandra 2011b, Marinucci et al. 2012, Merloni et al. 2014).”
• The subarcsecond mid-infrared view of local active galactic nuclei – II. The mid-infrared–X-ray correlation (2015, background): “Furthermore, Panessa et al. (2006) argue that the XMM-Newton data on this source is significantly contaminated by off-nuclear emission and thus not usable to extract information about the nucleus.”
• TOWARD THE STANDARD POPULATION SYNTHESIS MODEL OF THE X-RAY BACKGROUND: EVOLUTION OF X-RAY LUMINOSITY AND ABSORPTION FUNCTIONS OF ACTIVE GALACTIC NUCLEI INCLUDING COMPTON-THICK POPULATIONS (2014, methodology): “…for type 1 and type 2 AGNs; θinc = { arccos(1− (1− cosθoa)/2)) [for type− 1] arccos(cosθoa/2)) [for type− 2] (9) According to the torus geometry in the Brightman & Nandra (2011a) model, the torus column densityNtorusH is taken to be the same as the line-of-sight column densityNH in type-2…”