Evolution of dust abundance and grain size distribution at high redshift

2012 ◽  
Author(s):  
Hiroyuki Hirashita
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
High Redshift

scholarly journals Galaxy simulation with the evolution of grain size distribution

2019 ◽  
Author(s):  
Shohei Aoyama ◽  
Hiroyuki Hirashita ◽  
Kentaro Nagamine
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Interstellar Dust ◽  
High Redshift ◽  
Disc Galaxy ◽  
Chemical Enrichment ◽  
Spatially Resolved ◽  
Grid Points ◽  
Gas Ratio

Abstract We compute the evolution of interstellar dust in a hydrodynamic simulation of an isolated disc galaxy. We newly implement the evolution of full grain size distribution by sampling 32 grid points on the axis of the grain radius. We solve it consistently with the chemical enrichment and hydrodynamic evolution of the galaxy. This enables us to theoretically investigate spatially resolved evolution of grain size distribution in a galaxy. The grain size distribution evolves from a large-grain-dominated ($\gtrsim 0.1\,\rm{\mu m}$) phase to a small-grain production phase, eventually converging to a power-law-like grain size distribution similar to the so-called MRN distribution. We find that the small-grain abundance is higher in the dense ISM in the early epoch (t ≲ 1 Gyr) because of efficient dust growth by accretion, while coagulation makes the small-grain abundance less enhanced in the dense ISM later. This leads to steeper extinction curves in the dense ISM than in the diffuse ISM in the early phase, while they show the opposite trend later. The radial trend of extinction curves is described by faster evolution in the inner part. We also confirm that the simulation reproduces the observed relation between dust-to-gas ratio and metallicity, and the radial gradients of dust-to-gas ratio and dust-to-metal ratio in nearby galaxies. Since the above change in the grain size distribution occurs in t ∼ 1 Gyr, the age and density dependence of grain size distribution has a significant impact on the extinction curves even at high redshift.

scholarly journals Expected dust grain-size distributions in galaxies detected by ALMA at z > 7

2019 ◽  
Vol 490 (1) ◽  
pp. 540-549 ◽  
Author(s):  
Hsin-Min Liu ◽  
Hiroyuki Hirashita
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Galaxy Evolution ◽  
Grain Size Distribution ◽  
High Redshift ◽  
Size Distributions ◽  
Total Dust ◽  
Dust Sources ◽  
Grain Size Distributions ◽  
Different Grain Size

ABSTRACT The dust properties in high-redshift galaxies provide clues to the origin of dust in the Universe. Although dust has been detected in galaxies at redshift z > 7, it is difficult to constrain the dominant dust sources only from the total dust amount. Thus, we calculate the evolution of grain-size distribution, expecting that different dust sources predict different grain-size distributions. Using the star formation time-scale and the total Baryonic mass constrained by the data in the literature, we calculate the evolution of grain-size distribution. To explain the total dust masses in ALMA-detected z > 7 galaxies, the following two solutions are possible: (i) high dust condensation efficiency in stellar ejecta and (ii) efficient accretion (dust growth by accreting the gas-phase metals in the interstellar medium). We find that these two scenarios predict significantly different grain-size distributions: in (i), the dust is dominated by large grains ($a\gtrsim 0.1\,{\mu m}$, where a is the grain radius), while in (ii), the small-grain ($a\lesssim 0.01\,{\mu m}$) abundance is significantly enhanced by accretion. Accordingly, extinction curves are expected to be much steeper in (ii) than in (i). Thus, we conclude that extinction curves provide a viable way to distinguish the dominant dust sources in the early phase of galaxy evolution.

scholarly journals Spectral energy distributions of dust and PAHs based on the evolution of grain size distribution in galaxies

2020 ◽  
Vol 499 (2) ◽  
pp. 3046-3060
Author(s):  
Hiroyuki Hirashita ◽  
Weining Deng ◽  
Maria S Murga
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Galaxy Evolution ◽  
Grain Size Distribution ◽  
Theoretical Calculations ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Intermediate Stage ◽  
Spectral Energy ◽  
Spatially Resolved

ABSTRACT Based on a one-zone evolution model of grain size distribution in a galaxy, we calculate the evolution of infrared spectral energy distribution (SED), considering silicate, carbonaceous dust, and polycyclic aromatic hydrocarbons (PAHs). The dense gas fraction (ηdense) of the interstellar medium (ISM), the star formation time-scale (τSF), and the interstellar radiation field intensity normalized to the Milky Way value (U) are the main parameters. We find that the SED shape generally has weak mid-infrared (MIR) emission in the early phase of galaxy evolution because the dust abundance is dominated by large grains. At an intermediate stage (t ∼ 1 Gyr for τSF = 5 Gyr), the MIR emission grows rapidly because the abundance of small grains increases drastically by the accretion of gas-phase metals. We also compare our results with observational data of nearby and high-redshift (z ∼ 2) galaxies taken by Spitzer. We broadly reproduce the flux ratios in various bands as a function of metallicity. We find that small ηdense (i.e. the ISM dominated by the diffuse phase) is favoured to reproduce the 8 $\rm{\mu m}$ intensity dominated by PAHs for both the nearby and the z ∼ 2 samples. A long τSF raises the 8 $\rm{\mu m}$ emission to a level consistent with the nearby low-metallicity galaxies. The broad match between the theoretical calculations and the observations supports our understanding of the grain size distribution, but the importance of the diffuse ISM for the PAH emission implies the necessity of spatially resolved treatment for the ISM.

Grain size distribution in evaporated permalloy films

1970 ◽  
Vol 2 (2) ◽  
pp. K69-K73 ◽  
Author(s):  
M. Reinbold ◽  
H. Hoffmann
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution
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