x-cigale: fitting AGN/galaxy SEDs from X-ray to infrared

Yang, Guang; Boquien, M.; Buat, V.; Burgarella, D.; Ciesla, L.; Duras, F.; Stalevski, Marko; Brandt, W. N.; Papovich, Casey

doi:10.1093/mnras/stz3001

Cited by 162 publications

(28 citation statements)

References 86 publications

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“…We also utilize X-CIGALE (Yang et al 2020) to identify BL AGNs from their optical-to-IR SEDs in combination with the X-ray flux level. We do not provide redshift information to X-CIGALE and allow X-CIGALE fit redshift as a free parameter.…”

Section: B2 Sed-template-fitting-based Classificationmentioning

confidence: 99%

“…We do not provide redshift information to X-CIGALE and allow X-CIGALE fit redshift as a free parameter. We adopt a delayed exponentially declining star formation history, a Chabrier initial mass function (Chabrier 2003), the extinction law from Calzetti et al (2000), the dust emission template from Dale et al (2014), the AGN component SKIRTOR (which is established based on Stalevski et al 2012Stalevski et al , 2016, and the X-ray module following Yang et al (2020). Details of the fitting parameters are given in Table 8.…”

Section: B2 Sed-template-fitting-based Classificationmentioning

confidence: 99%

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The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields

Brandt

Chen

et al. 2021

ApJS

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We present the X-ray point-source catalogs in two of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields, W-CDF-S (4.6 deg 2 ) and ELAIS-S1 (3.2 deg 2 ), aiming to fill the gap between deep pencil-beam X-ray surveys and shallow X-ray surveys over large areas. The W-CDF-S and ELAIS-S1 regions were targeted with 2.3 and 1.0 Ms of XMM-Newton observations, respectively; 1.8 and 0.9 Ms exposures remain after flare filtering. The survey in W-CDF-S has a flux limit of 1.0 × 10 −14 erg cm −2 s −1 over 90% of its area in the 0.5-10 keV band; 4053 sources are detected in total. The survey in ELAIS-S1 has a flux limit of 1.3 × 10 −14 erg cm −2 s −1 over 90% of its area in the 0.5-10 keV band; 2630 sources are detected in total. Reliable optical-to-IR multiwavelength counterpart candidates are identified for ≈89% of the sources in W-CDF-S and ≈87% of the sources in ELAIS-S1. A total of 3129 sources in W-CDF-S and 1957 sources in ELAIS-S1 are classified as active galactic nuclei (AGNs). We also provide photometric redshifts for X-ray sources; ≈84% of the 3319/2001 sources in W-CDF-S/ELAIS-S1 with optical-to-near-IR forced photometry available have either spectroscopic redshifts or high-quality photometric redshifts. The completion of the XMM-Newton observations in the W-CDF-S and ELAIS-S1 fields marks the end of the XMM-SERVS survey data gathering. The ≈12,000 pointlike X-ray sources detected in the whole ≈13 deg 2 XMM-SERVS survey will benefit future large-sample AGN studies.

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Section: B2 Sed-template-fitting-based Classificationmentioning

confidence: 99%

Section: B2 Sed-template-fitting-based Classificationmentioning

confidence: 99%

The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields

Brandt

Chen

et al. 2021

ApJS

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“…from UV to radio) spectral energy distribution (SED) of AGN host galaxies using several components that can each be attributed to either a galactic or a nuclear origin (e.g. Noll et al 2009;Calistro Rivera et al 2016;Robotham et al 2020;Yang et al 2020). Often, however, these depend on modelled grids of templates to represent galaxy and AGN emission, which are idealized cases containing many free parameters and hence subject to uncertainties and degeneracies.…”

mentioning

confidence: 99%

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

Bernhard

Tadhunter

Mullaney

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Measuring the star-forming properties of AGN hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1–1000 μm) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates, and introduce the spectral energy distribution fitting code iragnsep. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local (z < 0.3), low-to-high luminosity AGNs (i.e. Lbol$~\sim ~10^{42-46}$ erg s−1), selected from the 105-month Swift–BAT X-ray survey, which have archival Spitzer–IRS spectra and Herschel photometry. We first built a set of seven galaxy templates using a sample of 55 star-forming galaxies selected via infrared diagnostics. Using these templates, combined with a flexible model for the AGN contribution, we extracted the intrinsic infrared emission of our AGN sample. We further demonstrate that we can reduce the diversity in the intrinsic shapes of AGN spectral energy distributions down to a set of three AGN templates, of which two represent AGN continuum, and one represents silicate emission. Our results indicate that, on average, the contribution of AGNs to the far-infrared (λ ≳ 50 μm) is not as high as suggested by some recent work. We further show that the need for two infrared AGN continuum templates could be related to nuclear obscuration, where one of our templates appears dominated by the emission of the extended polar dust.

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“…Moreover, having a sufficient number of photometric points would allow us to break the SF-AGN emission degeneracy and to estimate the AGN properties using SED-fitting decomposition techniques (jointly with additional instruments at different wavelengths) when spectra are not available. Although X-ray photometry and/or low-resolution spectroscopic data may not be used in SED fitting (but see X-CIGALE, Yang et al 2020), X-ray information could be crucial to select the templates to fit in the IR.…”

Section: Sed Fittingmentioning

confidence: 99%

The role of SPICA-like missions and the Origins Space Telescope in the quest for heavily obscured AGN and synergies with Athena

Barchiesi

Pozzi

Vignali

et al. 2021

Publ. Astron. Soc. Aust.

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In the black hole (BH)–galaxy co-evolution framework, most of the star formation (SF) and the BH accretion are expected to take place in highly obscured conditions. The large amount of gas and dust absorbs most of the UV-to-soft-X radiation and re-emits it at longer wavelengths, mostly in the IR. Thus, obscured active galactic nuclei (AGN) are very difficult to identify in optical or X-ray bands but shine bright in the IR. Moreover, X-ray background (XRB) synthesis models predict that a large fraction of the yet-unresolved XRB is due to the most obscured (Compton thick, CT: N $_{\text{H}}\ge 10^{24} \,\mathrm{cm}^{-2}$ ) of these AGN. In this work, we investigate the synergies between putative IR missions [using SPace Infrared telescope for Cosmology and Astrophysics (SPICA), proposed for European Space Agency (ESA)/M5 but withdrawn in 2020 October, and Origins Space Telescope, OST, as ‘templates’] and the X-ray mission Athena (Advanced Telescope for High ENergy Astrophysics), which should fly in early 2030s, in detecting and characterising AGN, with a particular focus on the most obscured ones. Using an XRB synthesis model, we estimated the number of AGN and the number of those which will be detected in the X-rays by Athena. For each AGN, we associated an optical-to-Far InfraRed (FIR) spectral energy distribution (SED) from observed AGN with both X-ray data and SED decomposition and used these SEDs to check if the AGN will be detected by SPICA-like or OST at IR wavelengths. We expect that, with the deepest Athena and SPICA-like (or OST) surveys, we will be able to photometrically detect in the IR more than 90% of all the AGN (down to $L_{2-10\text{keV}} \sim 10^{42}\,\mathrm{erg\ s}^{-1}$ and up to $z \sim 10$ ) predicted by XRB synthesis modeling, and we will detect at least half of them in the X-rays. The spectroscopic capabilities of the OST can provide ${\approx}51\,000$ and ${\approx}3\,400$ AGN spectra with $R= 300$ at 25–588 $\unicode[Times]{x03BC}$ m in the wide and deep surveys, respectively, the last one up to $z\approx 4$ . Athena will be extremely powerful in detecting and discerning moderate- and high-luminosity AGN, allowing us to properly select AGN even when the mid-IR torus emission is ‘hidden’ by the host galaxy contribution. We will constrain the intrinsic luminosity and the amount of obscuration for $\sim\!20\%$ of all the AGN (and $\sim\!50\%$ of those with $L_{2-10\text{keV}} > 3.2 \times 10^{43}\,\mathrm{erg\ s}^{-1}$ ) using the X-ray spectra provided by Athena WFI. We find that the most obscured and elusive CT-AGN will be exquisitely sampled by SPICA-like mission or OST and that Athena will allow a fine characterisation of the most luminous ones. This will provide a significant step forward in the process of placing stronger constraints on the yet-unresolved XRB and investigating the BH accretion rate evolution up to very high redshift ( $z \ge 4$ ).

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x-cigale: fitting AGN/galaxy SEDs from X-ray to infrared

Cited by 162 publications

References 86 publications

The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields

The XMM-SERVS Survey: XMM-Newton Point-source Catalogs for the W-CDF-S and ELAIS-S1 Fields

The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

The role of SPICA-like missions and the Origins Space Telescope in the quest for heavily obscured AGN and synergies with Athena

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