تقرير
SDSS IV MaNGA -- Metallicity and ionisation parameter in local star-forming galaxies from Bayesian fitting to photoionisation models
| العنوان: | SDSS IV MaNGA -- Metallicity and ionisation parameter in local star-forming galaxies from Bayesian fitting to photoionisation models |
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| المؤلفون: | Mingozzi, M., Belfiore, F., Cresci, G., Bundy, K., Bershady, M., Bizyaev, D., Blanc, G., Boquien, M., Drory, N., Fu, H., Maiolino, R., Riffel, R., Schaefer, A., Storchi-Bergmann, T., Telles, E., Tremonti, C., Zakamska, N., Zhang, K. |
| المصدر: | A&A 636, A42 (2020) |
| سنة النشر: | 2020 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies |
| الوصف: | We measured gas-phase metallicity, ionisation parameter and dust extinction for 1795 representative local star-forming galaxies using integral field spectroscopy from the SDSS-IV MaNGA survey. We self-consistently derive these quantities by comparing observed line fluxes with photoionisation models using a Bayesian framework. We also present the first comprehensive study of the [SIII]$\lambda\lambda$9069,9532 nebular lines, which have long been predicted to be ideal tracers of the ionisation parameter. Unfortunately, we find that current photoionisation models substantially over-predict [SIII] lines intensity, while broadly reproducing other observed optical line ratios. We discuss how to nonetheless make use of the information provided by [SIII] lines by setting a prior on the ionisation parameter. Following this approach, we derive spatially-resolved maps and radial profiles of metallicity and ionisation parameter. The metallicity radial profiles are comparable with previous works, with metallicity declining toward the outer parts and a flattening in the central regions, in agreement with infall models of galaxy formation, that predict that spiral discs build up through accretion of material, which leads to an inside-out growth. On the other hand, ionisation parameter radial profiles are flat for low-mass galaxies, while their slope becomes positive as galaxy mass increases. However, the ionisation parameter maps we obtain are clumpy, especially for low-mass galaxies. Ionisation parameter is tightly correlated with the H$\alpha$ equivalent width [EW(H$\alpha$)], following a nearly universal relation, which we attribute to the change of the spectral shape of ionising sources due to ageing of HII regions. We derive a positive correlation between ionisation parameter and metallicity at fixed EW(H$\alpha$), in disagreement with previous theoretical works expecting an anti-correlation. Comment: 27 pages, 23 figures, resubmitted to A&A |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1051/0004-6361/201937203 |
| URL الوصول: | http://arxiv.org/abs/2002.05744 |
| رقم الأكسشن: | edsarx.2002.05744 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1051/0004-6361/201937203 |
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