Galaxy Formation and Evolution: Low Surface Brightness Galaxies
Galaxy Formation and Evolution: Low Surface Brightness Galaxies
复制标题
DOI：
10.1046/j.1365-8711.1998.01731.x
复制
发表时间：
1998-04
影响因子：
4.8
通讯作者：
R. Jimenez;P. Padoan;F. Matteucci;A. Heavens
中科院分区：
文献类型：
--
作者：
R. Jimenez;P. Padoan;F. Matteucci;A. Heavens
我们详细研究了低表面亮度星系（LSB）与普通星系的区别仅仅是因为它们形成具有大自旋参数的晕的假设，并利用施密特定律计算了星星的形成率，假设气体的下落与表面密度的关系与银河系模型中的相同。我们建立恒星种群模型，预测颜色，光谱和化学丰度。我们比较了我们的预测与观测值的金属丰度和颜色的LSB星系，并发现与所有观测值非常吻合。特别是，综合颜色、颜色梯度、表面亮度和金属丰度与年龄大于7 Gyr的模型的LSB观测值和晕旋参数的高值（λ > 0.05）非常匹配。我们还计算了宇宙中由于LSB而产生的整体星星形成率（SFR），并表明它具有比正常圆盘相应的SFR更大的红移演化。我们进一步比较了我们模型中[Zn/H]红移的演化与Pettini等（1997）在阻尼莱曼α系统中观测到的结果，并表明阻尼莱曼α系统的丰度与预测的不同半径处的LSB丰度是一致的。最后，我们展示了晕坍缩所需的晚红移可能会限制涨落的功率谱.关键词：星系：形成-星系：演化-星系：螺旋-星系：恒星含量。
ABSTRACT We investigatein detail the hypothesisthat low surfacebrightnessgalaxies(LSB) differfrom ordinary galaxies simply because they form in halos with large spin parameters.We compute star formation rates using the Schmidt law, assuming the same gas infalldependence on surface density as used in models of the Milky Way. We build stellarpopulation models, predicting colours, spectra, and chemical abundances. We compareour predictions with observed values of metallicity and colours for LSB galaxies andfind excellent agreement with all observables. In particular, integrated colours, colourgradients, surface brightness and metallicity match very well to the observed valuesof LSBs for models with ages larger than 7 Gyr and high values (λ > 0.05) for thespin parameter of the halos. We also compute the global star formation rate (SFR)in the Universe due to LSBs and show that it has a flatter evolution with redshiftthan the corresponding SFR for normal discs. We furthermore compare the evolutionin redshift of [Zn/H] for our models to those observed in Damped Lyman α systemsby Pettini et al. (1997) and show that Damped Lyman α systems abundances areconsistent with the predicted abundances at different radii for LSBs. Finally, we showhow the required late redshift of collapse of the halo may constrain the power spectrumof fluctuations.Key words: galaxies: formation – galaxies: evolution – galaxies: spiral – galaxies:stellar content.