论文标题

关于灰尘积累和高红移时尘埃遮挡的理论线索

Theoretical clues about dust accumulation and galaxy obscuration at high and low redshift

论文作者

Barbosa-Santos, J. H., Neto, Gastão B. Lima, Friaça, Amancio C. S.

论文摘要

由于宇宙之星的时代在$ z \ sim 2 $上达到峰值,因此大多数在高质量星系中被遮盖了,而在低质量星系中,辐射逃生毫无障碍。在电离时期,进化,灰尘遮盖的星系的存在是对星系形成和进化模型的挑战。通过化学动力学进化模型,我们研究了在星系中建立大部分灰尘所需的恒星形成和灰尘产生,初始bary质量从$ 7.5 \ times 10^{7} $ 〜m $ $ $ _ \ odot $到$ 2.0 \ $ 2.0 \ times 10^{12} {12} $ 〜M $ _ $ _ \ odot $。还选择了恒星形成效率以表示从不规则矮人到巨型椭圆星系的恒星形成速率。我们从\ citep [] [case a] {dwek19988 volution}采用了灰尘凝血效率,以及一个较低的效率一个(案例B),大约是Case A小的五倍A。计算了这些参数的所有可能组合,总结了四十个不同的情况。我们发现,在高恒星地层系统中,在星形峰值之前,ISM规则中的尘埃吸收规则,使这些系统几乎对灰尘凝结效率不敏感。在低恒星形成系统中,情况A和B之间的差异持续更长的时间,主要是在小星系中。因此,小的不规则星系应该是区分不同防尘源的最佳场所。在我们的观察样本中,从文献中获取,对于恒星质量和恒星形成速率,尘埃气比的分布往往比尘埃质量更大。由于气体,恒星,灰尘和恒星形成速率之间的联系,尘土飞扬与尘埃星图是银河系和尘埃演化的良好示踪剂。但是,该模型并未同时约束所有这些数量。新一代设施(例如JWST,ELT,VLT和Spica)将是必不可少的,以限制整个宇宙时间的尘埃形成。

Since the epoch of cosmic star formation peak at $z \sim 2$, most of it is obscured in high mass galaxies, while in low mass galaxies the radiation escapes unobstructed. During the reionization epoch, the presence of evolved, dust obscured galaxies are a challenge to galaxy formation and evolution models. By means of a chemodynamical evolution model, we investigate the star formation and dust production required to build up the bulk of dust in galaxies with initial baryonic mass ranging from $7.5 \times 10^{7}$~M$_\odot$ to $2.0 \times 10^{12}$~M$_\odot$. The star formation efficiency was also chosen to represent the star formation rate from irregular dwarf to giant elliptical galaxies. We adopted a dust coagulation efficiency from \citep[][Case A]{dwek1998evolution} as well as a lower efficiency one (Case B), about five times smaller than Case A. All possible combination of these parameters was computed, summing forty different scenarios. We find that in high stellar formation systems the dust accretion in ISM rules over stellar production before the star formation peak, making these systems almost insensible to dust coagulation efficiency. In low star formation systems, the difference between Case A and B lasts longer, mainly in small galaxies. Thus, small irregular galaxies should be the best place to discriminate different dust sources. In our observational sample, taken from the literature, dust-to-gas ratio tends to be more spread only than dust mass, for both stellar mass and star formation rate. Dust-to-gas vs. dust-to-star diagram is a good tracer for both galaxy and dust evolution, due to the link between gas, star, dust and star formation rate. However, the model do not constrain simultaneously all this quantities. The new generation facilities (such as JWST, ELT, VLT and SPICA) will be indispensable to constrain dust formation across the cosmic time.

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