scholarly journals Dust evolution in zoom-in cosmological simulations of galaxy formation

2021 ◽  
Author(s):  
Gian Luigi Granato ◽  
Cinthia Ragone-Figueroa ◽  
Antonela Taverna ◽  
Laura Silva ◽  
Milena Valentini ◽  
...  
Keyword(s):  
Size Distribution ◽  
Galaxy Formation ◽  
Initial Conditions ◽  
Spectral Energy Distribution ◽  
Previous Treatment ◽  
Spectral Energy ◽  
Zoom In ◽  
Set Up ◽  
Dust Evolution ◽  
Disc Galaxies

Abstract We present cosmological zoom-in hydro-dynamical simulations for the formation of disc galaxies, implementing dust evolution and dust promoted cooling of hot gas. We couple an improved version of our previous treatment of dust evolution, which adopts the two-size approximation to estimate the grain size distribution, with the MUPPI star formation and feedback sub-resolution model. Our dust evolution model follows carbon and silicate dust separately. To distinguish differences induced by the chaotic behaviour of simulations from those genuinely due to different simulation set-up, we run each model six times, after introducing tiny perturbations in the initial conditions. With this method, we discuss the role of various dust-related physical processes and the effect of a few possible approximations adopted in the literature. Metal depletion and dust cooling affect the evolution of the system, causing substantial variations in its stellar, gas and dust content. We discuss possible effects on the Spectral Energy Distribution of the significant variations of the size distribution and chemical composition of grains, as predicted by our simulations during the evolution of the galaxy. We compare dust surface density, dust-to-gas ratio and small-to-large grain mass ratio as a function of galaxy radius and gas metallicity predicted by our fiducial run with recent observational estimates for three disc galaxies of different masses. The general agreement is good, in particular taking into account that we have not adjusted our model for this purpose.

scholarly journals Stellar Population Models

2012 ◽  
Vol 8 (S295) ◽  
pp. 272-281 ◽  
Author(s):  
Claudia Maraston
Keyword(s):  
Galaxy Formation ◽  
Stellar Population ◽  
High Redshift ◽  
Spectral Energy Distribution ◽  
Cosmic Time ◽  
Mass Function ◽  
Initial Mass Function ◽  
Asymptotic Giant Branch ◽  
Spectral Energy ◽  
Massive Galaxies

AbstractModelling stellar populations in galaxies is a key approach to gain knowledge on the still elusive process of galaxy formation as a function of cosmic time. In this review, after a summary of the state-of-art, I discuss three aspects of the modelling, that are particularly relevant to massive galaxies, the focus of this symposium, at low and high-redshift. These are the treatment of the Thermally-Pulsating Asymptotic Giant Branch phase, evidences of an unusual Initial Mass Function, and the effect of modern stellar libraries on the model spectral energy distribution.

Stellar Population Models of Distant Radio Galaxies

1996 ◽  
Vol 175 ◽  
pp. 588-590
Author(s):  
D. Villani ◽  
S. Di Serego Alighieri
Keyword(s):  
Energy Distribution ◽  
Galaxy Formation ◽  
Stellar Population ◽  
Spectral Energy Distribution ◽  
Formation Rate ◽  
Stellar Populations ◽  
Radio Galaxies ◽  
Initial Mass Function ◽  
Spectral Energy ◽  
The Galaxy

Stellar populations of high redshift radio galaxies (HzRG) (z up to 4.2) are the oldest stellar systems known, that is the ones formed at the earliest cosmological epochs. Therefore they are the best objects for providing us with information about the epoch of galaxy formation. The information on the stellar populations in HzRG are obtained from the study of their Integrated Spectral Energy Distribution (ISED) which are gathered both from spectra and integrated magnitudes. The most common approach for the interpretation of colors and spectral features of the energy distribution of galaxies is the Evolutionary Population Synthesis (EPS), which has been introduced for the first time by Tinsley in 1972. EPS models have often been used in the past to interpret the ISED of HzRG (Chambers & Charlot 1990; Lilly & Longair 1984; di Serego Alighieri et al. 1994) in order to draw conclusions on the age of the stellar populations and therefore on the epoch of galaxy formation. The results are sometimes conflicting and a number of very recent EPS models have become available (Bressan et al. 1995; Bruzual & Charlot 1993; Buzzoni 1989; Guiderdoni & Rocca-Volmerange 1987): we are therefore analysing the differences between the various EPS models with the aim of assessing their suitability to study the stellar population at early epochs. The EPS models assume for stars a given Initial Mass Function(IMF) as well as a Star Formation Rate (SFR). Then one can compute the number of stars with given mass present in the galaxy as a function of time. The position of each star in the HR diagram is determined by means of the isochrones, which are calculated from stellar evolutionary models. The ISED of a galaxy is obtained from the superposition of the spectra of single stars obtained from a stellar spectral library. Thus these models describe the galaxy ISED as a function of the time, giving a complete evolutionary picture.

scholarly journals A hierarchical bayesian dust SED model and its application to the nearby universe

2019 ◽  
Vol 15 (S341) ◽  
pp. 138-142
Author(s):  
Frédéric Galliano
Keyword(s):  
Spectral Energy Distribution ◽  
Distribution Model ◽  
Spectral Energy ◽  
Nearby Galaxy ◽  
Hierarchical Bayesian ◽  
Galaxy Sample ◽  
Hierarchical Bayesian Method ◽  
The One ◽  
Dust Evolution ◽  
Gas Ratio

AbstractIn this paper, I review several dust evolution studies based on the DustPedia nearby galaxy sample. I first present the dust spectral energy distribution model, implementing a hierarchical Bayesian method, that we have developed. I then discuss the dust evolution trends we have derived among (integrated) and within (resolved) galaxies. In particular, we show that the trend of dust-to-gas ratio with metallicity is clearly non-linear, indicating the need for grain growth in the interstellar medium. Our trend is closer to the one derived with damped Lyα systems than what was suggested by previous studies. We finally demonstrate the universal processing of small amorphous carbon grains by stellar photons.

scholarly journals Searching for debris discs in the 30 Myr open cluster IC 4665

2020 ◽  
Vol 641 ◽  
pp. A156
Author(s):  
N. Miret-Roig ◽  
N. Huélamo ◽  
H. Bouy
Keyword(s):  
Open Cluster ◽  
Spectral Energy Distribution ◽  
Young Stars ◽  
Spectral Energy ◽  
Virtual Observatory ◽  
Planetary Formation ◽  
Infrared Excess ◽  
Solar Type ◽  
Dust Evolution ◽  
Host Stars

Context. Debris discs orbiting young stars are key to understanding dust evolution and the planetary formation process. We take advantage of a recent membership analysis of the 30 Myr nearby open cluster IC 4665 based on the Gaia and DANCe surveys to revisit the disc population of this cluster. Aims. We aim to study the disc population of IC 4665 using Spitzer (MIPS and IRAC) and WISE photometry. Methods. We use several colour–colour diagrams with empirical photospheric sequences to detect the sources with an infrared excess. Independently, we also fit the spectral energy distribution (SED) of our debris-disc candidates with the Virtual Observatory SED analyser (VOSA) which is capable of automatically detecting infrared excesses and provides effective temperature estimates. Results. We find six candidate debris-disc host stars (five with MIPS and one with WISE), two of which are new candidates. We estimate a disc fraction of 24 ± 10% for the B–A stars, where our sample is expected to be complete. This is similar to what has been reported in other clusters of similar ages (Upper Centaurus Lupus, Lower Centaurus Crux, the β Pictoris moving group, and the Pleiades). For solar-type stars we find a disc fraction of 9 ± 9%, which is lower than that observed in regions with comparable ages. Conclusions. Our candidate debris-disc host stars are excellent targets to be studied with ALMA or the future James Webb Space Telescope (JWST).

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 Extrasolar asteroid mining as forensic evidence for extraterrestrial intelligence

2011 ◽  
Vol 10 (4) ◽  
pp. 307-313 ◽  
Author(s):  
Duncan H. Forgan ◽  
Martin Elvis
Keyword(s):  
Energy Distribution ◽  
Size Distribution ◽  
Raw Materials ◽  
Spectral Energy Distribution ◽  
Chemical Species ◽  
Spectral Energy ◽  
Natural Phenomena ◽  
Forensic Evidence ◽  
Extraterrestrial Intelligence ◽  
Asteroids And Comets

AbstractThe development of civilizations such as ours into spacefaring, multi-planet entities requires significant raw materials to construct vehicles and habitats. Interplanetary debris, including asteroids and comets, may provide such a source of raw materials. In this article, we present the hypothesis that extraterrestrial intelligences (ETIs) engaged in asteroid mining may be detectable from Earth. Considering the detected disc of debris around Vega as a template, we explore the observational signatures of targeted asteroid mining (TAM), such as unexplained deficits in chemical species, changes in the size distribution of debris and other thermal signatures that may be detectable in the spectral energy distribution (SED) of a debris disc. We find that individual observational signatures of asteroid mining can be explained by natural phenomena, and as such they cannot provide conclusive detections of ETIs. But, it may be the case that several signatures appearing in the same system will prove harder to model without extraterrestrial involvement. Therefore, signatures of TAM are not detections of ETI in their own right, but as part of ‘piggy-back’ studies carried out in tandem with conventional debris disc research, they could provide a means of identifying unusual candidate systems for further study using other search for extra terrestrial intelligence (SETI) techniques.

scholarly journals Dust Emission from IRC+10216

2000 ◽  
Vol 177 ◽  
pp. 399-404
Author(s):  
Željko Ivezić ◽  
Moshe Elitzur
Keyword(s):  
Size Distribution ◽  
Equations Of Motion ◽  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Angular Size ◽  
Infrared Emission ◽  
Spectral Energy ◽  
Condensation Zone ◽  
Single Temperature ◽  
Dust Condensation

Infrared emission from the dust shell around IRC+10216 is analysed in detail, employing a self-consistent model for radiatively driven winds around late-type stars that couples the equations of motion and radiative transfer in the dust. The resulting model provides agreement with the wealth of available data, including the spectral energy distribution in the range 0.5-1000 μm, and visibility and array observations. Previous conclusions about two dust shells, derived from modelling the data with a few single-temperature components of different radii, are not supported by our results. The IR properties vary with the stellar phase, reflecting changes in both the dust condensation radius r1 and the overall optical depth τ - as the luminosity increases from minimum to maximum, r1 increases while τ decreases. We find that the angular size of the dust condensation zone varies from 0.″3 at minimum light to 0.″5 at maximum. The shortage of flux at short wavelengths encountered in previous studies is resolved by employing a grain size distribution that includes grains larger than ∼ 0.1 μm, required also for the visibility fits. This distribution is in agreement with the one recently proposed by Jura in a study that probed the outer regions of the envelope. Since our constraints on the size distribution mostly reflect the envelope's inner regions, the agreement of these independent studies is evidence against significant changes in grain sizes through effects like sputtering or grain growth after the initial formation at the dust condensation zone.

scholarly journals Dust modeling of the combined ALMA and SPHERE datasets of HD 163296

2018 ◽  
Vol 614 ◽  
pp. A24 ◽  
Author(s):  
G. A. Muro-Arena ◽  
C. Dominik ◽  
L. B. F. M. Waters ◽  
M. Min ◽  
L. Klarmann ◽  
...  
Keyword(s):  
Near Infrared ◽  
Thermal Emission ◽  
Scattered Light ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Dust Grains ◽  
Outer Disk ◽  
Group I ◽  
Dust Evolution ◽  
Small Dust

Context. Multiwavelength observations are indispensable in studying disk geometry and dust evolution processes in protoplanetary disks. Aims. We aim to construct a three-dimensional model of HD 163296 that is capable of reproducing simultaneously new observations of the disk surface in scattered light with the SPHERE instrument and thermal emission continuum observations of the disk midplane with ALMA. We want to determine why the spectral energy distribution of HD 163296 is intermediary between the otherwise well-separated group I and group II Herbig stars. Methods. The disk was modeled using the Monte Carlo radiative transfer code MCMax3D. The radial dust surface density profile was modeled after the ALMA observations, while the polarized scattered light observations were used to constrain the inclination of the inner disk component and turbulence and grain growth in the outer disk. Results. While three rings are observed in the disk midplane in millimeter thermal emission at ~80, 124, and 200 AU, only the innermost of these is observed in polarized scattered light, indicating a lack of small dust grains on the surface of the outer disk. We provide two models that are capable of explaining this difference. The first model uses increased settling in the outer disk as a mechanism to bring the small dust grains on the surface of the disk closer to the midplane and into the shadow cast by the first ring. The second model uses depletion of the smallest dust grains in the outer disk as a mechanism for decreasing the optical depth at optical and near-infrared wavelengths. In the region outside the fragmentation-dominated regime, such depletion is expected from state-of-the-art dust evolution models. We studied the effect of creating an artificial inner cavity in our models, and conclude that HD 163296 might be a precursor to typical group I sources.

scholarly journals The post-Herschel view of intrinsic AGN emission: constructing templates for galaxy and AGN emission at IR wavelengths

2021 ◽  
Vol 503 (2) ◽  
pp. 2598-2621
Author(s):  
E Bernhard ◽  
C Tadhunter ◽  
J R Mullaney ◽  
L P Grimmett ◽  
D J Rosario ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Spectral Energy Distribution ◽  
Far Infrared ◽  
Infrared Emission ◽  
Host Galaxy ◽  
Spectral Energy ◽  
Distribution Fitting ◽  
Star Forming ◽  
Galaxy Formation And Evolution ◽  
Infrared Diagnostics

ABSTRACT Measuring the star-forming properties of active galactic nucleus (AGN) hosts is key to our understanding of galaxy formation and evolution. However, this topic remains debated, partly due to the difficulties in separating the infrared (i.e. 1–1000 ${\rm \mu m}$) emission into AGN and star-forming components. Taking advantage of archival far-infrared data from Herschel, we present a new set of AGN and galaxy infrared templates and introduce the spectral energy distribution fitting code iragnsep. Both can be used to measure infrared host galaxy properties, free of AGN contamination. To build these, we used a sample of 100 local (z < 0.3), low-to-high luminosity AGNs (i.e. Lbol$\ \sim \ 10^{42-46}$ erg s−1), selected from the 105-month Swift–BAT X-ray survey, which have archival Spitzer–IRS spectra and Herschel photometry. We first built a set of seven galaxy templates using a sample of 55 star-forming galaxies selected via infrared diagnostics. Using these templates, combined with a flexible model for the AGN contribution, we extracted the intrinsic infrared emission of our AGN sample. We further demonstrate that we can reduce the diversity in the intrinsic shapes of AGN spectral energy distributions down to a set of three AGN templates, of which two represent AGN continuum, and one represents silicate emission. Our results indicate that, on average, the contribution of AGNs to the far-infrared (λ ≳ 50 ${\rm \mu m}$) is not as high as suggested by some recent work. We further show that the need for two infrared AGN continuum templates could be related to nuclear obscuration, where one of our templates appears dominated by the emission of the extended polar dust.

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