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تسجيل مستخدم جديدEstimating dust attenuation from galactic spectra. II. Stellar and gas attenuation in star-forming and diffuse ionized gas regions in MaNGA
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We investigate the dust attenuation in both stellar populations and ionized gas in kpc-scale regions in nearby galaxies, using integral field spectroscopy data from MaNGA MPL-9. We identify star-forming (HII) and diffuse ionized gas (DIG) regions from MaNGA datacubes. From the stacked spectrum of each region, we measure the stellar attenuation, $E(B-V)_{rm star}$, using the technique developed by Li et al.(2020), as well as the gas attenuation, $E(B-V)_{rm gas}$, from the Balmer decrement. We then examine the correlation of $E(B-V)_{rm star}$, $E(B-V)_{rm gas}$, $E(B-V)_{rm gas}-E(B-V)_{rm star}$ and $E(B-V)_{rm star}/E(B-V)_{rm gas}$ with 16 regional/global properties, and for regions with different $rm H{alpha}$ surface brightnesses ($Sigma_{rm Halpha}$). We find a stronger correlation between $E(B-V)_{rm star}$ and $E(B-V)_{rm gas}$ in regions of higher $Sigma_{rm Halpha}$. Luminosity-weighted age ($t_L$) is found to be the property that is the most strongly correlated with $E(B-V)_{rm star}$, and consequently with $E(B-V)_{rm gas}-E(B-V)_{rm star}$ and $E(B-V)_{rm star}/E(B-V)_{rm gas}$. At fixed $Sigma_{rm Halpha}$, $log_{10}t_L$ is linearly and negatively correlated with $E(B-V)_{rm star}/E(B-V)_{rm gas}$ at all ages. Gas-phase metallicity and ionization level are important for the attenuation in the gas. Our results indicate that the ionizing source for DIG regions is likely distributed in the outer-skirt of galaxies, while for HII regions our results can be well explained by the two-component dust model of Charlot & Fall (2000).
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