Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies

Riffel, Rogemar A.; Rodríguez-Ardila, A.; Brotherton, Michael S.; Peletier, Reynier F.; Vazdekis, Alexandre; Riffel, Rogemar A.; Martins, Lucimara P.; Bonatto, Charles Jose; Dametto, N. Z.; Dahmer-Hahn, L G; Runnoe, Jessie C.; Pastoriza, M. G.; Chies-Santos, Ana L.; Trevisan, M.

doi:10.1093/mnras/stz1077

Cited by 37 publications

(57 citation statements)

References 96 publications

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“…We then found that NGC 1222 (aorkey = 9071872) has a matching SED to He2-10, suggesting the presence of a starburst. In fact, NGC 1222 is reported to be a lenticular S0 galaxy (Riffel et al 2019) and was undetected in X-rays (Su et al 2015). In addition, we found that WISEAJ155616.05 + 395137.8 (aorkey = 22128896) also has an SED which is identical to He2-10 and NGC 1222 and yet is reported as a Wolf-Rayet galaxy (Chen et al 2018) and is therefore consistent with IR powered by star formation.…”

Section: Figure B1supporting

confidence: 56%

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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Section: Figure B1supporting

confidence: 56%

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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“…The colour coding is the same as for the [Fe ii]/Paβ vs. H2/Brγ diagram. The dotted vertical lines in these panels represent the limits of ratios in photoionised objects and in shock dominated objects -[Fe ii]/[P ii]= 2 and 20, respectively (Oliva et al 2001;Storchi-Bergmann et al 2009) -see also Riffel et al (2019). All galaxies show ratios larger than 2, with the highest values corresponding to the HLR regions in the excitation maps shown in the bottom-left panels of Figs.…”

Section: Emission-line Ratio Diagnostic Diagramsmentioning

confidence: 92%

“…The [Fe ii] and molecular hydrogen emission lines are among the most prominent spectral features in the near-infrared (near-IR) spectra of active galactic nuclei (AGN), but which excitation mechanisms are responsible for their emission in AGN are still in debate (e.g. Rodríguez-Ardila et al 2004Riffel et al 2006b;Dors et al 2012;Riffel et al 2013aRiffel et al , 2019Lamperti et al 2017). Such lines can be produced by the AGN or young stars radiation field or by shocks, as for example from supernovae explosions or interaction of a radio jet with the ambient gas.…”

Section: Introductionmentioning

confidence: 99%

Gemini NIFS survey of feeding and feedback processes in nearby active galaxies – I. Stellar kinematics

Riffel

Storchi‐Bergmann

Riffel

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We use the Gemini Near-Infrared Integral Field Spectrograph (NIFS) to map the stellar kinematics of the inner few hundred parsecs of a sample of 16 nearby Seyfert galaxies, at a spatial resolution of tens of parsecs and spectral resolution of 40 km s −1. We find that the line-of-sight (LOS) velocity fields for most galaxies are well reproduced by rotating disc models. The kinematic position angle (PA) derived for the LOS velocity field is consistent with the large-scale photometric PA. The residual velocities are correlated with the hard X-ray luminosity, suggesting that more luminous active galactic nuclei have a larger impact in the surrounding stellar dynamics. The central velocity dispersion values are usually higher than the rotation velocity amplitude, what we attribute to the strong contribution of bulge kinematics in these inner regions. For 50 per cent of the galaxies, we find an inverse correlation between the velocities and the h 3 Gauss-Hermitte moment, implying red wings in the blueshifted side and blue wings in the redshifted side of the velocity field, attributed to the movement of the bulge stars lagging the rotation. Two of the 16 galaxies (NGC 5899 and Mrk 1066) show an S-shape zero velocity line, attributed to the gravitational potential of a nuclear bar. Velocity dispersion (σ) maps show rings of low-σ values (∼50-80 km s −1) for four objects and 'patches' of low σ for six galaxies at 150-250 pc from the nucleus, attributed to young/ intermediate age stellar populations.

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“…Attempts to match the colors of large samples of galaxies from the near-ultraviolet (near-UV) to the near-IR have been found to leave significant residuals, sometimes leading authors to discard near-IR data in part of their analysis (Taylor et al 2011). Star formation histories derived from optical and near-IR data separately, or from a given data set with different population synthesis models, still differ significantly (Powalka et al 2017;Baldwin et al 2018;Dahmer-Hahn et al 2018;Dametto et al 2019;Riffel et al 2019). A part of the problem certainly lies in the theoretical modeling of advanced phases of stellar evolution, but it is also worth questioning the stellar spectral libraries.…”

Section: Introductionmentioning

confidence: 99%

A comparison between X-shooter spectra and PHOENIX models across the HR-diagram

Lançon

Gonneau

Verro

et al. 2021

A&A

Self Cite

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Aims. The path towards robust near-infrared extensions of stellar population models involves the confrontation between empirical and synthetic stellar spectral libraries across the wavelength ranges of photospheric emission. Indeed, the theory of stellar emission enters all population synthesis models, even when this is only implicit in the association of fundamental stellar parameters with empirical spectral library stars. With its near-ultraviolet to near-infrared coverage, the X-shooter Spectral Library (XSL) allows us to examine to what extent models succeed in reproducing stellar energy distributions (SEDs) and stellar absorption line spectra simultaneously. Methods. As a first example, this study compares the stellar spectra of XSL with those of the Göttingen Spectral Library, which are based on the PHOENIX synthesis code. The comparison was carried out both separately in the three arms of the X-shooter spectrograph known as UVB, VIS and NIR, and jointly across the whole spectrum. We did not discard the continuum in these comparisons; only reddening was allowed to modify the SEDs of the models. Results. When adopting the stellar parameters published with data release DR2 of XSL, we find that the SEDs of the models are consistent with those of the data at temperatures above 5000 K. Below 5000 K, there are significant discrepancies in the SEDs. When leaving the stellar parameters free to adjust, satisfactory representations of the SEDs are obtained down to about 4000 K. However, in particular below 5000 K and in the UVB spectral range, strong local residuals associated with intermediate resolution spectral features are then seen; the necessity of a compromise between reproducing the line spectra and reproducing the SEDs leads to dispersion between the parameters favored by various spectral ranges. We describe the main trends observed and we point out localized offsets between the parameters preferred in this global fit to the SEDs and the parameters in DR2. These depend in a complex way on the position in the Hertzsprung–Russell diagram (HRD). We estimate the effect of the offsets on bolometric corrections as a function of position in the HRD and use this for a brief discussion of their impact on the studies of stellar populations. A review of the literature shows that comparable discrepancies are mentioned in studies using other theoretical and empirical libraries.

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Optical/NIR stellar absorption and emission-line indices from luminous infrared galaxies

Cited by 37 publications

References 96 publications

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

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

Gemini NIFS survey of feeding and feedback processes in nearby active galaxies – I. Stellar kinematics

A comparison between X-shooter spectra and PHOENIX models across the HR-diagram

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