The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects

Lutz, D.; Maiolino, R.; Spoon, H. W. W.; Moorwood, A. F. M.

doi:10.1051/0004-6361:20035838

Cited by 312 publications

(485 citation statements)

References 62 publications

(44 reference statements)

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“…Finally, the horizontal dotted line at L X = 10 42 erg s −1 denotes the upper limit to X-ray emission due to star-forming processes (Tzanavaris et al 2006). Lutz et al (2004). Finally, we show the luminosity-dependent line predicted by Maiolino et al (2007).…”

Section: X /L 6 Ratiomentioning

confidence: 71%

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X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

Georgantopoulos

Dasyra²,

Rovilos³

et al. 2011

A&A

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Observations with the IRS spectrograph onboard Spitzer have found many sources with very deep Si features at 9.7 μm, that have optical depths of τ > 1. Since it is believed that a few of these systems in the local Universe are associated with Compton-thick active galactic nuclei (hereafter AGN), we set out to investigate whether the presence of a strong Si absorption feature is a good indicator of a heavily obscured AGN. We compile X-ray spectroscopic observations available in the literature on the optically-thick (τ 9.7 μm > 1) sources from the 12 μm IRAS Seyfert sample. We find that the majority of the high-τ optically confirmed Seyferts (six out of nine) in the 12 μm sample are probably Compton-thick. Thus, we provide direct evidence of a connection between mid-IR optically-thick galaxies and Compton-thick AGN, with the success rate being close to 70% in the local Universe. This is at least comparable to, if not better than, other rates obtained with photometric information in the mid to far-IR, or even mid-IR to X-rays. However, this technique cannot provide complete Compton-thick AGN samples, i.e., there are many Compton-thick AGN that do not display significant Si absorption, with the most notable example being NGC 1068. After assessing the validity of the high 9.7 μm optical-depth technique in the local Universe, we attempt to construct a sample of candidate Compton-thick AGN at higher redshifts. We compile a sample of seven high-τ Spitzer sources in the Great Observatories Origins Deep Survey (GOODS) and five in the Spitzer First-Look Survey. All these have been selected to have no PAH features (EW 6.2 μm < 0.3 μm) to maximise the probability that they are bona-fide AGN. Six out of the seven GOODS sources have been detected in X-rays, while for the five FLS sources only X-ray flux upper limits are available. The high X-ray luminosities (L X > 10 42 erg s −1 ) of the detected GOODS sources corroborates that these are AGN. For FLS, ancillary optical spectroscopy reveals hidden nuclei in two more sources. SED fitting can support the presence of an AGN in the vast majority of sources. Owing to the limited photon statistics, we cannot derive useful constraints from X-ray spectroscopy on whether these sources are Compton-thick. However, the low L X /L 6 μm luminosity ratios, suggest that at least four out of the six detected sources in GOODS may be associated with Compton-thick AGN.

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Section: X /L 6 Ratiomentioning

confidence: 71%

“…One of the most reliable proxies of the intrinsic power of an AGN is considered to be the mid-IR 6 μm luminosity (e.g. Lutz et al 2004;Maiolino et al 2007). This wavelength region can contain significant emission from the hot dust heated by the AGN, and thus provides a reliable diagnostic of the AGN power.…”

Section: X /L 6 Ratiomentioning

confidence: 99%

X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

Georgantopoulos

Dasyra²,

Rovilos³

et al. 2011

A&A

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“…On the other hand, due to the high energies involved in the accretion process, X-rays are good tracers of the AGN power. For this reason, the Xray MIR correlation has been widely used in the literature to investigate the origin of the MIR emission in different types of AGN (Lutz et al 2004;Ramos Almeida et al 2007;Horst et al 2008;Gandhi et al 2009;Levenson et al 2009;Ichikawa et al 2012;Mason et al 2012;Matsuta et al 2012;Sazonov et al 2012;Asmus et al 2015;Mateos et al 2015).…”

Section: Mir Correlations With Agn and Sf Indicatorsmentioning

confidence: 99%

“…Lutz et al 2004;Ramos Almeida et al 2007;Horst et al 2008;Gandhi et al 2009;Levenson et al 2009;Sazonov et al 2012). For example, Ramos Almeida et al (2007) found a slope of 0.8 by using nuclear fluxes obtained from ISOCAM data at 6.75 µm.…”

Section: Mir Correlations With Agn and Sf Indicatorsmentioning

confidence: 99%

The nuclear and extended mid-infrared emission of Seyfert galaxies

García-Bernete¹,

Almeida²,

Acosta–Pulido³

et al. 2016

Mon. Not. R. Astron. Soc.

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We present subarcsecond resolution mid-infrared (MIR) images obtained with 8-10 m-class ground-based telescopes of a complete volume-limited (D L <40 Mpc) sample of 24 Seyfert galaxies selected from the Swift/BAT nine month catalog. We use those MIR images to study the nuclear and circumnuclear emission of the galaxies. Using different methods to classify the MIR morphologies on scales of ∼400 pc, we find that the majority of the galaxies (75-83%) are extended or possibly extended and 17-25% are point-like. This extended emission is compact and it has low surface brightness compared with the nuclear emission, and it represents, on average, ∼30% of the total MIR emission of the galaxies in the sample. We find that the galaxies whose circumnuclear MIR emission is dominated by star formation show more extended emission (650±700 pc) than AGN-dominated systems (300±100 pc). In general, the galaxies with point-like MIR morphologies are face-on or moderately inclined (b/a∼0.4-1.0), and we do not find significant differences between the morphologies of Sy1 and Sy2. We used the nuclear and circumnuclear fluxes to investigate their correlation with different AGN and SF activity indicators. We find that the nuclear MIR emission (the inner ∼70 pc) is strongly correlated with the X-ray emission (the harder the X-rays the better the correlation) and with the [O IV] λ25.89 µm emission line, indicating that it is AGN-dominated. We find the same results, although with more scatter, for the circumnuclear emission, which indicates that the AGN dominates the MIR emission in the inner ∼400 pc of the galaxies, with some contribution from star formation.

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“…The far-infrared emission from Herschel provides a clean tracer of host galaxy star-formation (Pier & Krolik 1992), making these data of particular importance to study the host galaxies of AGNs (Pier & Krolik 1992;Efstathiou & Rowan-Robinson 1995;Lutz et al 2004;Fritz et al 2006;Schweitzer et al 2006;Netzer et al 2007;Schartmann et al 2008;Shao et al 2010;Mullaney et al 2011;Rosario et al 2012;Magdis et al 2013;Delvecchio et al 2014). Indeed, the XMM-Newton AO13 survey was specifically designed to overlap existing Herschel coverage, since similar far-infrared data will not be available in the foreseeable future.…”

Section: Herschelmentioning

confidence: 99%

THE 31 DEG² RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

LaMassa

Urry²,

Cappelluti

et al. 2016

ApJ

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We release the next installment of the Stripe 82 X-ray survey point-source catalog, which currently covers 31.3 deg 2 of the Sloan Digital Sky Survey (SDSS) Stripe 82 Legacy field. In total, 6181 unique X-ray sources are significantly detected with XMM-Newton (>5σ) and Chandra (>4.5σ). This catalog release includes data from XMM-Newton cycle AO 13, which approximately doubled the Stripe 82X survey area. The flux limits of the Stripe 82X survey are 8.7×10 −16 erg s −1 cm −2 , 4.7×10 −15 erg s −1 cm −2 , and 2.1×10 −15 erg s −1 cm −2 in the soft (0.5-2 keV), hard (2-10 keV), and full bands (0.5-10 keV), respectively, with approximate half-area survey flux limits of 5.4×10 −15 erg s −1 cm −2 , 2.9×10 −14 erg s −1 cm −2 , and 1.7×10 −14 erg s −1 cm −2 . We matched the X-ray source lists to available multi-wavelength catalogs, including updated matches to the previous release of the Stripe 82X survey; 88% of the sample is matched to a multi-wavelength counterpart. Due to the wide area of Stripe 82X and rich ancillary multi-wavelength data, including coadded SDSS photometry, mid-infrared WISE coverage, near-infrared coverage from UKIDSS and VISTA Hemisphere Survey, ultraviolet coverage from GALEX, radio coverage from FIRST, and far-infrared coverage from Herschel, as well as existing ∼30% optical spectroscopic completeness, we are beginning to uncover rare objects, such as obscured high-luminosity active galactic nuclei at high-redshift. The Stripe 82X point source catalog is a valuable data set for constraining how this population grows and evolves, as well as for studying how they interact with the galaxies in which they live.

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The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects

Cited by 312 publications

References 62 publications

X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

The nuclear and extended mid-infrared emission of Seyfert galaxies

THE 31 DEG² RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

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The relation between AGN hard X-ray emission and mid-infrared continuum from ISO spectra: Scatter and unification aspects

Cited by 312 publications

References 62 publications

X-ray observations of highly obscuredτ9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

X-ray observations of highly obscuredτ9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

The nuclear and extended mid-infrared emission of Seyfert galaxies

THE 31 DEG2 RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

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X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

X-ray observations of highly obscuredτ_9.7μm > 1 sources: an efficient method for selecting Compton-thick AGN?

THE 31 DEG² RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG