Photoionization analysis of chemo-dynamical dwarf galaxies model

Autor(en)

Gerhard Hensler, Bohdan Melekh, Simone Recchi, Oleg Buhajenko

Abstrakt

Photoionization modeling allows following the transport, the emergence, and the absorption of photons taking into account all important processes in nebular plasmas. Such modeling needs the spatial distribution of density, chemical abundances and temperature, which can be provided by chemo-dynamical simulations (ChDS) of dwarf galaxies. We perform multi-component photoionization modeling (MPhM) of the ionized gas using 2-D ChDSs of dwarf galaxies.We calculate emissivity maps for important nebular emission lines. Their intensities are used to derive the chemical abundance of oxygen by the so-called Te- and R23-me-thods. Some disagreements are found between oxygen abundances calculated with these methods and the ones coming from the ChDSs.We also investigate the fraction of ionizing radiation emitted in the star-forming region which is able to leak out the galaxy. The time- and direction-averaged escape fraction in our simulation is 0.35-0.4.Finally, we calculate the total Ha luminosity of our model galaxy and apply Kennicutt’s calibration to derive the star-formation rate. Comparing this value with the ’true’ rate in the ChDSs, we find that the Ha-based star-formation rate agrees with the true one only at the beginning of the simulation. Minor deviations arise later on and are due in part to the production of more energetic photons in the warm-hot gas, in part to the leakage of Lyman-continuum photons out of the galaxy.Moreover, the effect of an arbitrarily inserted thin dense shell of swept-up surrounding gas (with thickness smaller than the ChDS’s spatial resolution) is investigated as well.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

Ivan Franko National University of Lviv

Journal

IAU General Assembly Meeting

Band

22

Publikationsdatum

08-2015

Peer-reviewed

Ja

ÖFOS 2012

103004 Astrophysik

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/photoionization-analysis-of-chemodynamical-dwarf-galaxies-model(ce147101-ed97-44d4-9295-4a1c1a32b642).html