The properties of satellite galaxies in simulations of galaxy formation
The properties of satellite galaxies in simulations of galaxy formation
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DOI：
10.1111/j.1365-2966.2010.16690.x
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发表时间：
2009-09
影响因子：
4.8
通讯作者：
T. Okamoto;T. Okamoto;C. Frenk;A. Jenkins;T. Theuns;T. Theuns
中科院分区：
文献类型：
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作者：
T. Okamoto;T. Okamoto;C. Frenk;A. Jenkins;T. Theuns;T. Theuns
我们研究了在银河系大小的晕中星系形成的宇宙n体/光滑粒子流体动力学模拟中卫星星系的性质。由于卫星星系的势井较浅，因此对影响其气体含量的加热过程非常敏感。因此，它们的性质可以用来约束调节星系形成的反馈过程的性质。在我们的模拟中，我们假设超新星产生的所有能量都被用作动能来驱动星系风。我们的一些模拟产生了明亮的、以圆盘为主的星系。我们发现，风速ν w与暗物质的局部速度色散σ（因而风质量载荷η w∝σ -2）成正比的风模型，使得卫星中的恒星形成是偶发性的，很好地重现了观测到的卫星光度函数（低至M ν = -7），并与在局部群卫星中观测到的光度-金属丰度关系相匹配。相比之下，假设风速恒定的模型会过度产生微弱的卫星，并预测出不正确的光度-金属丰度关系。因此，我们的模拟表明，在卫星星系的尺度上运行的反馈过程应该产生星系外流，其质量负荷与势的深度成反比。
We investigate the properties of satellite galaxies in cosmological N-body/smooth particle hydrodynamics simulations of galaxy formation in Milky Way-sized haloes. Because of their shallow potential wells, satellite galaxies are very sensitive to heating processes which affect their gas content. Their properties can therefore be used to constrain the nature of feedback processes that regulate galaxy formation. In our simulations, we assume that all the energy produced by supernovae is used as kinetic energy to drive galactic winds. Several of our simulations produce bright, disc-dominated galaxies. We find that wind models in which the wind speed, ν w , is proportional to the local velocity dispersion of the dark matter, σ (and thus the wind mass-loading, η w ∝ σ ―2 ), make star formation in satellites sporadic, reproduce the observed satellite luminosity function reasonably well (down to M ν = -7) and match the luminosity-metallicity relation observed in the Local Group satellites. By contrast, models that assume a constant wind speed overproduce faint satellites and predict an incorrect luminosity-metallicity relation. Our simulations therefore suggest that the feedback processes that operate on the scale of satellite galaxies should generate galactic outflows whose mass-loading varies inversely with the depth of the potential.