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تسجيل مستخدم جديدThe SAMI Galaxy Survey: understanding observations of large-scale outflows at low redshift with EAGLE simulations
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This work presents a study of galactic outflows driven by stellar feedback. We extract main sequence disc galaxies with stellar mass $10^9le$ M$_{star}/$M$_{odot} le 5.7times10^{10}$ at redshift $z=0$ from the highest resolution cosmological simulation of the Evolution and Assembly of GaLaxies and their Environments (EAGLE) set. Synthetic gas rotation velocity and velocity dispersion ($sigma$) maps are created and compared to observations of disc galaxies obtained with the Sydney-AAO Multi-object Integral field spectrograph (SAMI), where $sigma$-values greater than $150$ km s$^{-1}$ are most naturally explained by bipolar outflows powered by starburst activity. We find that the extension of the simulated edge-on (pixelated) velocity dispersion probability distribution depends on stellar mass and star formation rate surface density ($Sigma_{rm SFR}$), with low-M$_{star}/$low-$Sigma_{rm SFR}$ galaxies showing a narrow peak at low $sigma$ ($sim30$ km s$^{-1}$) and more active, high-M$_{star}/$high-$Sigma_{rm SFR}$ galaxies reaching $sigma>150$ km s$^{-1}$. Although supernova-driven galactic winds in the EAGLE simulations may not entrain enough gas with T $<10^5$ K compared to observed galaxies, we find that gas temperature is a good proxy for the presence of outflows. There is a direct correlation between the thermal state of the gas and its state of motion as described by the $sigma$-distribution. The following equivalence relations hold in EAGLE: $i)$ low-$sigma$ peak $,Leftrightarrow,$ disc of the galaxy $,Leftrightarrow,$ gas with T $<10^5$ K; $ii)$ high-$sigma$ tail $,Leftrightarrow,$ galactic winds $,Leftrightarrow,$ gas with T $ge 10^5$ K.
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