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.

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 Towards a census of high-redshift dusty galaxies with Herschel

2018 ◽  
Vol 614 ◽  
pp. A33 ◽  
Author(s):  
D. Donevski ◽  
V. Buat ◽  
F. Boone ◽  
C. Pappalardo ◽  
M. Bethermin ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Far Infrared ◽  
Virgo Cluster ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Redshift Distribution ◽  
Star Forming

Context. Over the last decade a large number of dusty star-forming galaxies has been discovered up to redshift z = 2 − 3 and recent studies have attempted to push the highly confused Herschel SPIRE surveys beyond that distance. To search for z ≥ 4 galaxies they often consider the sources with fluxes rising from 250 μm to 500 μm (so-called “500 μm-risers”). Herschel surveys offer a unique opportunity to efficiently select a large number of these rare objects, and thus gain insight into the prodigious star-forming activity that takes place in the very distant Universe. Aims. We aim to implement a novel method to obtain a statistical sample of 500 μm-risers and fully evaluate our selection inspecting different models of galaxy evolution. Methods. We consider one of the largest and deepest Herschel surveys, the Herschel Virgo Cluster Survey. We develop a novel selection algorithm which links the source extraction and spectral energy distribution fitting. To fully quantify selection biases we make end-to-end simulations including clustering and lensing. Results. We select 133 500 μm-risers over 55 deg2, imposing the criteria: S500 > S350 > S250, S250 > 13.2 mJy and S500 > 30 mJy. Differential number counts are in fairly good agreement with models, displaying a better match than other existing samples. The estimated fraction of strongly lensed sources is 24+6-5% based on models. Conclusions. We present the faintest sample of 500 μm-risers down to S250 = 13.2 mJy. We show that noise and strong lensing have an important impact on measured counts and redshift distribution of selected sources. We estimate the flux-corrected star formation rate density at 4 < z < 5 with the 500 μm-risers and find it to be close to the total value measured in far-infrared. This indicates that colour selection is not a limiting effect to search for the most massive, dusty z > 4 sources.

scholarly journals Cosmological models and the brightness profile of distant galaxies

2009 ◽  
Vol 5 (H15) ◽  
pp. 329-329
Author(s):  
I. Olivares-Salaverri ◽  
Marcelo B. Ribeiro
Keyword(s):  
Cosmological Model ◽  
Observational Data ◽  
Galaxy Evolution ◽  
Surface Brightness ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Surface Profile ◽  
Galactic Evolution ◽  
Spectral Energy ◽  
Distant Galaxies

This work aims to determine the feasibility of an assumed cosmological model by means of a detailed analysis of the brightness profiles of distant galaxies. Starting from the theory of Ellis & Perry (1979) connecting the angular diameter distance obtained from a relativistic cosmological model and the detailed photometry of galaxies, we assume the presently most accepted cosmology with Λ ¬ = 0 and seek to predict the brightness profile of a galaxy in a given redshift z. To do so, we have to make assumptions concerning the galactic brightness structure and evolution, assuming a scenario where the specific emitted surface brightness Be,νe can be characterized as, Be,νe (r,z) = B0(z)J(νe,z)f[r(z)/a(z)]. Here r is the intrinsic galactic radius, νe the emitted frequency, B0(z) the central surface brightness, J(νe,z) the spectral energy distribution (SED), f[r(z)/a(z)] characterizes the shape of the surface profile distribution and a(z) is the scaling radius. The dependence on z is due to the galactic evolution. As spacetime curvature affects the received surface brightness, the reciprocity theorem (Ellis 1971) allows us to predict the theoretical received surface brightness. So, we are able to compare the theoretical surface brightness with its equivalent observational data already available for high redshift galaxies in order to test the consistency of the assumed cosmological model. The function f[r(z)/a(z)] is represented in the literature by various different shapes, like the Hubble, Hubble-Oemler and Abell-Mihalas single parameter profiles, characterizing the galactic surface brightness quite well when the disk or bulge dependence is dominant. Sérsic and core-Sérsic profiles use two or more parameters and reproduce the galactic profile almost exactly (Trujillo et al. 2004). If we consider all wavelengths, the theory tells us that the total intensity is equal to the surface brightness, so the chosen bandwidth should include most of the SED. In order to analyze only the effect of the cosmological model in the surface brightness and minimize evolutionary effects, we assume that there exists a homogeneous class of objects, whose properties are similar in all redshifts, allowing us to carry out comparisons at different values of z. Studying the parameters that affect the galactic evolution, as well as in others geometrical tests, we will be able to infer some possible galaxy evolution which could reproduce a theoretical surface brightness profile, in order to compare with the observational data and reach conclusions about the observational feasibility of the underlying cosmological model.

scholarly journals The MUSEHubbleUltra Deep Field Survey

2017 ◽  
Vol 608 ◽  
pp. A9 ◽  
Author(s):  
E. Ventou ◽  
T. Contini ◽  
N. Bouché ◽  
B. Epinat ◽  
J. Brinchmann ◽  
...  
Keyword(s):  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Spectral Energy ◽  
Close Pair ◽  
Major Merger ◽  
Stellar Masses ◽  
Good Agreement ◽  
Close Pairs

We provide, for the first time, robust observational constraints on the galaxy major merger fraction up toz≈ 6 using spectroscopic close pair counts. Deep Multi Unit Spectroscopic Explorer (MUSE) observations in theHubbleUltra Deep Field (HUDF) andHubbleDeep Field South (HDF-S) are used to identify 113 secure close pairs of galaxies among a parent sample of 1801 galaxies spread over a large redshift range (0.2 <z< 6) and stellar masses (107−1011M⊙), thus probing about 12 Gyr of galaxy evolution. Stellar masses are estimated from spectral energy distribution (SED) fitting over the extensive UV-to-NIR HST photometry available in these deepHubblefields, addingSpitzerIRAC bands to better constrain masses for high-redshift (z⩾ 3) galaxies. These stellar masses are used to isolate a sample of 54 major close pairs with a galaxy mass ratio limit of 1:6. Among this sample, 23 pairs are identified at high redshift (z⩾ 3) through their Lyαemission. The sample of major close pairs is divided into five redshift intervals in order to probe the evolution of the merger fraction with cosmic time. Our estimates are in very good agreement with previous close pair counts with a constant increase of the merger fraction up toz≈ 3 where it reaches a maximum of 20%. At higher redshift, we show that the fraction slowly decreases down to about 10% atz≈ 6. The sample is further divided into two ranges of stellar masses using either a constant separation limit of 109.5M⊙or the median value of stellar mass computed in each redshift bin. Overall, the major close pair fraction for low-mass and massive galaxies follows the same trend. These new, homogeneous, and robust estimates of the major merger fraction sincez≈ 6 are in good agreement with recent predictions of cosmological numerical simulations.

scholarly journals Model for Infrared Properties of Extremely Young Galaxies

2004 ◽  
Vol 217 ◽  
pp. 214-215
Author(s):  
T. T. Takeuchi ◽  
H. Hirashita ◽  
T. T. Ishii ◽  
L. K. Hunt ◽  
A. Ferrara
Keyword(s):  
Energy Distribution ◽  
Size Distribution ◽  
Galaxy Evolution ◽  
Early Stage ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Dust Size Distribution ◽  
Infrared Spectral

We constructed a model of the infrared spectral energy distribution for very young galaxies by taking into account the dust size distribution in the early stage of galaxy evolution.

scholarly journals Spectroscopy with the JWST Advanced Deep Extragalactic Survey (JADES) - the NIRSpec/NIRCAM GTO galaxy evolution project

2019 ◽  
Vol 15 (S352) ◽  
pp. 342-346
Author(s):  
Andrew J. Bunker
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Rest Frame ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
Balmer Line ◽  
Chemical Abundances ◽  
Star Forming

AbstractI present an overview of the JWST Advanced Deep Extragalactic Survey (JADES), a joint program of the JWST/NIRCam and NIRSpec Guaranteed Time Observations (GTO) teams involving 950 hours of observation. We will target two well-studied fields with excellent supporting data (e.g., from HST-CANDELS): GOODS-North and South, including the Ultra Deep Field. The science goal of JADES is to chart galaxy evolution at z > 2, and potentially out to z > 10, using the rest-frame optical and near-IR though observations from ≍ 1–5μm. Multi-colour NIRCam imaging with 9 filters will enable photometric redshifts and the application of the Lyman break technique out to unprecedented distances. NIRSpec spectroscopy (with spectral resolving powers of R = 100, 1000 & 2700) will measure secure spectroscopic redshifts of the photometrically-selected population, as well as stellar continuum slopes in the UV rest-frame, and hence study the role of dust, stellar population age, and other effects. Measuring emission lines can constrain the dust extinction, star formation rates, metallicity, chemical abundances, ionization and excitation mechanism in high redshift galaxies. Coupling NIRCam and NIRSpec observations will determine stellar populations (age, star formation histories, abundances) of galaxies and provide the information to correct their broad-band spectral energy distribution for likely line contamination. Potentially we can search for signatures of Population III stars such as HeII. We can address the contribution of star-forming galaxies at z > 7 to reionization by determining the faint end slope of the luminosity function and investigating the escape fraction of ionizing photons by comparing the UV stellar continuum with the Balmer-line fluxes.

scholarly journals Integrated photometric redshifts and SED fitting as tool for galaxy evolution studies

2012 ◽  
Vol 8 (S289) ◽  
pp. 292-295
Author(s):  
Ralf Kotulla
Keyword(s):  
Energy Distribution ◽  
Galaxy Evolution ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Photometric Redshifts ◽  
First Results ◽  
The Common ◽  
High Redshift Universe ◽  
Fixed Input

AbstractPhotometric redshifts, i.e. redshifts derived by comparing an observed spectral-energy distribution (SED) to a range of empirical or theoretical SED templates, are commonly used in studies of the high-redshift Universe. Often, the next step is to use these redshifts as fixed input parameters for SED fitting to derive physical properties for each galaxy. However, this two-step approach ignores degeneracies between redshift and, e.g., stellar mass. Here I present first results using an improved approach that integrates both methods. I find that mass determinations are, on average, three times more uncertain than they seem from the common two-step approach. If not accounted for, these underestimated uncertainties can impact our ability of making meaningful comparisons between observations and simulations of galaxy evolution.

scholarly journals Effects of rotational disruption on the evolution of grain size distribution in galaxies

2020 ◽  
Vol 494 (1) ◽  
pp. 1058-1070 ◽  
Author(s):  
Hiroyuki Hirashita ◽  
Thiem Hoang
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Size Distribution ◽  
Galaxy Evolution ◽  
Grain Size Distribution ◽  
Extinction Curve ◽  
Short Time Scale ◽  
Dust Grains ◽  
Grain Production ◽  
Dust Temperature

ABSTRACT Interstellar dust grains can be spun up by radiative torques, and the resulting centrifugal force may be strong enough to disrupt large dust grains. We examine the effect of this rotational disruption on the evolution of grain size distribution in galaxies. To this goal, we modify our previous model by assuming that rotational disruption is the major small-grain production mechanism. We find that rotational disruption can have a large influence on the evolution of grain size distribution in the following two aspects especially for composites and grain mantles (with tensile strength ∼107   erg cm −3). First, because of the short time-scale of rotational disruption, the small-grain production occurs even in the early phase of galaxy evolution. Therefore, even though stars produce large grains, the abundance of small grains can be large enough to steepen the extinction curve. Secondly, rotational disruption is important in determining the maximum grain radius, which regulates the steepness of the extinction curve. For compact grains with tensile strength ≳109   erg cm −3, the size evolution is significantly affected by rotational disruption only if the radiation field is as strong as (or the dust temperature is as high as) expected for starburst galaxies. For compact grains, rotational disruption predicts that the maximum grain radius becomes less than 0.2 $\rm{\mu m}$ for galaxies with a dust temperature ≳50 K.

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