On the Impact of Inclination-dependent Attenuation on Derived Star Formation Histories: Results from Disk Galaxies in the Great Observatories Origins Deep Survey Fields

Abstract

We develop and implement an inclination-dependent attenuation prescription for spectral energy distribution (SED) fitting and study its impact on derived star formation histories. We apply our prescription within the SED fitting code Lightning to a clean sample of 82, z = 0.21–1.35 disk-dominated galaxies in the Great Observatories Origins Deep Survey North and South fields. To compare our inclination-dependent attenuation prescription with more traditional fitting prescriptions, we also fit the SEDs with the inclination-independent Calzetti et al. (2000) attenuation curve. From this comparison, we find that fits to a subset of 58, z < 0.7 galaxies in our sample, utilizing the Calzetti et al. (2000) prescription, recover similar trends with inclination as the inclination-dependent fits for the far-UV-band attenuation and recent star formation rates. However, we find a difference between prescriptions in the optical attenuation (A V ) that is strongly correlated with inclination (p‐value < 10−11). For more face-on galaxies, with i ≲ 50°, (edge-on, i ≈ 90°), the average derived A V is 0.31 ± 0.11 magnitudes lower (0.56 ± 0.16 magnitudes higher) for the inclination-dependent model compared to traditional methods. Further, the ratio of stellar masses between prescriptions also has a significant (p‐value < 10−2) trend with inclination. For i = 0°–65°, stellar masses are systematically consistent between fits, with log 10 ( M ⋆ inc / M ⋆ Calzetti ) = − 0.05 ± 0.03 dex and scatter of 0.11 dex. However, for i ≈ 80°–90°, the derived stellar masses are lower for the Calzetti et al. (2000) fits by an average factor of 0.17 ± 0.03 dex and scatter of 0.13 dex. Therefore, these results suggest that SED fitting assuming the Calzetti et al. (2000) attenuation law potentially underestimates stellar masses in highly inclined disk-dominated galaxies.

Starduster: A Multiwavelength SED Model Based on Radiative Transfer Simulations and Deep Learning

“…Our predicted stellar mass is slightly overestimated compared with DG15, who measured the stellar mass using MAGPHYS (Da Cunha et al 2008). This difference is consistent with the study by Doore et al (2021), who found that inclinationindependent SED models could underestimate stellar mass. In addition, the different choices of the simple stellar population library could also impact the measurements of the stellar mass.…”

“…This is unrealistic, since the dust emission spectrum does not depend on inclination angle, while the UV to optical attenuation does. Doore et al (2021) found that including inclination dependence in SED fitting affects the estimation of stellar mass.…”

Elevated Hot Gas and High-mass X-Ray Binary Emission in Low-metallicity Galaxies: Implications for Nebular Ionization and Intergalactic Medium Heating in the Early Universe

“…Given the morphological variety and multiple components that are apparent for some of our galaxies, we chose to perform our own detailed photometric extraction and SED fitting of the available far-UV-to-mid-IR data to derive physical properties. We made use of the Lightning SED fitting code (see Eufrasio et al 2017), which fits broadband SEDs using a nonparametric star formation history (SFH) model, including prescriptions for attenuation and nebular and dust emission (see Doore et al 2021, for further details). A detailed account of the SED fitting of this sample and its results will be presented in a forthcoming paper (R. T. Eufrasio et al 2022, in preparation); however, for completeness, we describe the salient details and results below.…”

Elevated Hot Gas and High-Mass X-ray Binary Emission in Low Metallicity Galaxies: Implications for Nebular Ionization and Intergalactic Medium Heating in the Early Universe

“…Given the morphological variety and multiple components that are apparent for some of our galaxies, we chose to perform our own detailed photometric extraction and SED fitting of the available FUV-to-mid-IR data to derive physical properties. We made use of the Lightning SED fitting code (see Eufrasio et al 2017), which fits broadband SEDs using a non-parametric star-formation history (SFH) model, including prescriptions for attenuation and nebular and dust emission (see Doore et al 2021, for further details). A detailed account of the SED fitting of this sample and its results will be presented in a forthcoming paper (Eufrasio et al in-prep); however, for completeness, we describe the salient details and results below.…”

“…The SFH model specifies the intrinsic stellar and nebular spectral shape, which is further modified by attenuation by dust and re-emission of the absorbed radiation in the infrared. We modeled the attenuation using a threeparameter, modified Calzetti et al (2000) extinction curve (as described in Eufrasio et al 2017), and dust emission was modeled using Draine & Li (2007) models (with the fiveparameter implementation described in Doore et al 2021).…”