A Theory for the Variation of Dust Attenuation Laws in Galaxies

Narayanan, Desika; Conroy, Charlie; Davé, Romeel; Johnson, Benjamin D.; Popping, Gergö

doi:10.3847/1538-4357/aaed25

Cited by 129 publications

(220 citation statements)

References 151 publications

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“…This result is well known and is attributed to the star-dust geometry (Witt & Gordon 1996;Narayanan et al 2018). Narayanan et al (2018) have shown that steeper slopes may arise either by a large fraction of obscured young stars or by a significant fraction of unobscured old stars. Consequently, galaxies with older stellar populations exhibit steeper attenuation curves.…”

Section: Attenuation Lawmentioning

confidence: 59%

High-resolution, 3D radiative transfer modelling

Nersesian

Verstocken

Viaene

et al. 2020

A&A

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Context. Dust in late-type galaxies in the local Universe is responsible for absorbing approximately one third of the energy emitted by stars. It is often assumed that dust heating is mainly attributable to the absorption of ultraviolet and optical photons emitted by the youngest (≤ 100 Myr) stars. Consequently, thermal re-emission by dust at far-infrared wavelengths is often linked to the starformation activity of a galaxy. However, several studies argue that the contribution to dust heating by much older stellar populations might be more significant than previously thought. Advances in radiation transfer simulations finally allow us to actually quantify the heating mechanisms of diffuse dust by the stellar radiation field. Aims. As one of the main goals in the DustPedia project, we have developed a framework to construct detailed 3D stellar and dust radiative transfer models for nearby galaxies. In this study, we analyse the contribution of the different stellar populations to the dust heating in four nearby face-on barred galaxies: NGC 1365, M 83, M 95, and M 100. We aim to quantify the fraction directly related to young stellar populations, both globally and on local scales, and to assess the influence of the bar on the heating fraction. Methods. From 2D images we derive the 3D distributions of stars and dust. To model the complex geometries, we used SKIRT, a state-of-the-art 3D Monte Carlo radiative transfer code designed to self-consistently simulate the absorption, scattering, and thermal re-emission by the dust for arbitrary 3D distributions. Results. We derive global attenuation laws for each galaxy and confirm that galaxies of high specific star-formation rate have shallower attenuation curves and weaker UV bumps. On average, 36.5% of the bolometric luminosity is absorbed by dust in our galaxy sample. We report a clear effect of the bar structure on the radial profiles of the dust-heating fraction by the young stellar populations, and the dust temperature. We find that the young stellar populations are the main contributors to the dust heating, donating, on average ∼ 59% of their luminosity to this purpose throughout the galaxy. This dust-heating fraction drops to ∼ 53% in the bar region and ∼ 38% in the bulge region where the old stars are the dominant contributors to the dust heating. We also find a strong link between the heating fraction by the young stellar populations and the specific star-formation rate.

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Section: Attenuation Lawmentioning

confidence: 59%

High-resolution, 3D radiative transfer modelling

Nersesian

Verstocken

Viaene

et al. 2020

A&A

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“…attenuation curve. Narayanan et al (2018b) investigated the main influence on the diversity of the slopes on a sample of "zoom-in" simulated galaxies and they highlight the importance of the star-to-dust geometry, i.e. high fraction of obscured young and low fraction of obscured old stars steepen the attenuation curve.…”

Section: The Eagle Simulations and The Skirt Post-processingmentioning

confidence: 99%

Reproducing the Universe: a comparison between the EAGLE simulations and the nearby DustPedia galaxy sample

Trčka

Baes

Camps

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We compare the spectral energy distributions (SEDs) and inferred physical properties for simulated and observed galaxies at low redshift. We exploit UV-submillimetre mock fluxes of ∼ 7000 z=0 galaxies from the EAGLE suite of cosmological simulations, derived using the radiative transfer code skirt. We compare these to ∼ 800 observed galaxies in the UV-submillimetre range, from the DustPedia sample of nearby galaxies. To derive global properties, we apply the SED fitting code cigale consistently to both data sets, using the same set of ∼ 80 million models. The results of this comparison reveal overall agreement between the simulations and observations, both in the SEDs and in the derived physical properties, with a number of discrepancies. The optical and far-infrared regimes, and the scaling relations based upon the global emission, diffuse dust and stellar mass, show high levels of agreement. However, the mid-infrared fluxes of the EAGLE galaxies are overestimated while the far-UV domain is not attenuated enough, compared to the observations. We attribute these discrepancies to a combination of galaxy population differences between the samples, and limitations in the subgrid treatment of star-forming regions in the EAGLE-skirt post-processing recipe. Our findings show the importance of detailed radiative transfer calculations and consistent comparison, and provide suggestions for improved numerical models.

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“…The effects of dust distribution geometry and stellar-age-dependent extinction make the attenuation curve significantly different from the original extinction curve (e.g. Inoue 2005;Narayanan et al 2018). We leave radiation transfer calculations and comparisons with observed attenuation curves for future work.…”

Section: Implication For Starburst Galaxiesmentioning

confidence: 99%

Self-consistent modelling of aromatic dust species and extinction curves in galaxy evolution

Hirashita

Murga

2020

Monthly Notices of the Royal Astronomical Society

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We formulate and calculate the evolution of dust in a galaxy focusing on the distinction among various dust components -silicate, aromatic carbon, and non-aromatic carbon. We treat the galaxy as a one-zone object and adopt the evolution model of grain size distribution developed in our previous work. We further include aromatization and aliphatization (inverse reaction of aromatization). We regard small aromatic grains in a radius range of 3-50Å as polycyclic aromatic hydrocarbons (PAHs). We also calculate extinction curves in a consistent manner with the abundances of silicate and aromatic and non-aromatic carbonaceous dust. Our model nicely explains the PAH abundance as a function of metallicity in nearby galaxies. The extinction curve become similar to the Milky Way curve at age ∼ 10 Gyr, in terms of the carbon bump strength and the far-ultraviolet slope. We also apply our model to starburst galaxies by shortening the star formation time-scale (0.5 Gyr) and increasing the dense-gas fraction (0.9), finding that the extinction curve maintains bumpless shapes (because of low aromatic fractions), which are similar to the extinction curves observed in the Small Magellanic Cloud and high-redshift quasars. Thus, our model successfully explains the variety in extinction curve shapes at low and high redshifts.

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A Theory for the Variation of Dust Attenuation Laws in Galaxies

Cited by 129 publications

References 151 publications

High-resolution, 3D radiative transfer modelling

High-resolution, 3D radiative transfer modelling

Reproducing the Universe: a comparison between the EAGLE simulations and the nearby DustPedia galaxy sample

Self-consistent modelling of aromatic dust species and extinction curves in galaxy evolution

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