Optical/UV photons and even harder radiation components in galaxies are absorbed and scattered by dust and re-emitted at infrared wavelengths. For a better understanding of the obscured regions of the galaxies detailed models of the interaction of photons with dust grains and the propagation of light are required. A problem which can only be solved by means of numerical solution of the radiative transfer equation. As a prologue we present high angular mid IR observations of galactic nuclei in the spirit of future ELT instrumentation. Dust models are discussed, which are suited to fit the extinction curves and relevant to compute the emission of external galaxies. Self-consistent radiative transfer models have been presented in spherical symmetry for starburst nuclei, in two dimensions for disk galaxies (spirals) and, more recently, in three dimensional configuration of the dust density distribution. For the latter, a highlighting example is the clumpy dust tori around AGN. Modern advances in the field are reviewed which are either based on a more detailed physical picture or progress in computational sciences.
Probing the Dust Properties of Galaxies at Submillimetre Wavelengths II. Dust-to-gas mass ratio trends with metallicity and the submm excess in dwarf galaxies
Dust is ubiquitous in the Universe and its influence on the observed Electromagnetic (EM) radiation needs to be correctly addressed. In recent years it became clear that scattering of EM radiation from interstellar dust grains could change the local properties of the observed Cosmic Microwave Background (CMB) radiation. Here we consider the relevant processes of emission and scattering of EM radiation from spinning dust particles, and discuss their possible influence on the CMB. In particular, we show that scattered radiation can establish a correlation between different spectral components of…
New insight into the relation between star formation activity and dust content in galaxies
我们从SDSS DR 6中收集了3258个低红移星系的样本,并补充了GALEX,2 MASS和IRAS在远紫外和红外波段的光度观测。我们使用一个最近的,简单的,但物理动机的模型来解释所观察到的光谱能量分布的星系在这个样本中的物理参数描述的恒星形成历史和尘埃含量的统计约束。对1658个具有最高S/N观测值的星系的子样本的关注使我们能够最清楚地研究星系的各种物理性质之间的强相关性。我们发现,典型的尘埃质量的恒星形成与恒星形成率(SFR)的显着相关。我们还发现尘埃与恒星的质量比、尘埃质量与恒星形成率的比值以及弥漫的星际介质贡献的尘埃光度分数都与特定的SFR密切相关。与最近的化学和尘埃演化的星系模型的比较表明,这些相关性可能会出现,至少部分,从一个进化序列。当星系形成恒星时,它们的ISM变得富含尘埃,而气体供应的下降使比SFR降低。有趣的是,一个年轻的、活跃的恒星形成星系,其尘埃与气体的比例很低,可能仍然是高度尘埃,因为它含有大量的星际气体。这可能是重要的解释年轻的,富含气体的恒星形成星系在高红移的红外辐射。我们的研究提供了一个有用的本地参考未来的统计研究的恒星形成和尘埃的星系在高红移的性质。
We present a new dust extension to the Monte Carlo radiative transfer code crash, which enables it to simulate the propagation of ionizing radiation through mixtures of gas and dust. The new code is applied to study the impact of dust absorption on idealized galactic H II regions and on small scale reionization. We find that H II regions are reduced in size by the presence of dust, while their inner temperature and ionization structure remain largely unaffected. In the small scale reionization simulation, dust hardens ionization fronts and delays the overlap of ionized bubbles. This effect is …
In recent years, interstellar dust has become a crucial topic in the study of the high and very high redshift Universe. Evidence points to the existence of high dust masses in massive star forming galaxies already during the Epoch of Reionization, potentially affecting the escape of ionising photons into the intergalactic medium. Moreover, correctly estimating dust extinction at UV wavelengths is essential for precise ultra-violet luminosity function (UVLF) prediction and interpretation. In this paper, we investigate the impact of dust on the observed properties of high redshift galaxies, and …
The first dusty galaxies across $6 \lesssim z \lesssim 14$: Blue monsters, red monsters, and the bimodality of dust content in early galaxies
Instituto Nacional de Astrofísica, Óptica y Electrónica(墨西哥国家天体物理学、光学和电子学研究所);Instituto de Astrofísica de Canarias(加那利群岛天体物理研究所);Departamento de Astrofísica, Universidad de La Laguna(拉帕尔马大学天体物理学系);Astronomical Institute of the Czech Academy of Sciences(捷克科学院天文研究所)
Using NOEMA and ALMA 3mm line scans, we measure spectroscopic redshifts of six new dusty galaxies at 3.5<z<4.2 by solidly detecting [CI](1-0) and CO transitions. The sample was selected from the COSMOS and GOODS-North super-deblended catalogs with FIR photometric redshifts z>6, based on template IR spectrum energy distribution (SED) from known submillimeter galaxies at z=4--6. Dust SED analyses explain the photo-z overestimate from seemingly cold dust temperatures (Td) and steep Rayleigh-Jeans (RJ) slopes, providing additional examples of cold dusty galaxies impacted by the Cosmic Microwave Ba…
We compare observed far-infrared (FIR) galaxy spectral energy distributions (SEDs) at $z\sim6$ and theoretical predictions for first massive population II (Pop II) galaxies. Observed FIR SEDs at $z\gtrsim5$ are broad and shifted to bluer wavelengths when compared to galaxies at $z\sim3$. By implementing an analytical model for dust emission from Pop II massive galaxies,we were able to reproduce the observed behaviour as a consequence of the high energy densities and silicate-rich dust composition of high-$z$ model galaxies. As noted in a previous work, the non-blackbody nature of galaxy SEDs a…