Semi-Analytic Galaxy Evolution (SAGE): Model Calibration and Basic Results

This paper describes a new publicly available codebase for modelling galaxy formation in a cosmological context, the "Semi-Analytic Galaxy Evolution" model, or SAGE for short. SAGE is a significant update to that used in Croton et al. (2006) and has been rebuilt to be modular and customisable. The model will run on any N-body simulation whose trees are organised in a supported format and contain a minimum set of basic halo properties. In this work we present the baryonic prescriptions implemented in SAGE to describe the formation and evolution of galaxies, and their calibration for three N-body simulations: Millennium, Bolshoi, and GiggleZ. Updated physics include: gas accretion, ejection due to feedback, and reincorporation via the galactic fountain; a new gas cooling--radio mode active galactic nucleus (AGN) heating cycle; AGN feedback in the quasar mode; a new treatment of gas in satellite galaxies; and galaxy mergers, disruption, and the build-up of intra-cluster stars. Throughout, we show the results of a common default parameterization on each simulation, with a focus on the local galaxy population.Comment: 15 pages, 9 figures, accepted for publication in ApJS. SAGE is a publicly available codebase for modelling galaxy formation in a cosmological context, available at https://github.com/darrencroton/sage Questions and comments can be sent to Darren Croton: [email protected]

Seleção de equações para o paricá (Schizolobium amazonicum huber ex ducke), no estado de Roraima.

bitstream/item/130481/1/BP04-parica-helio.pd

Site selection for dendroclimatological studies with Bertholletia excelsa.

Edição dos abstracts do 24º IUFRO World Congress, 2014, Salt Lake City. Sustaining forests, sustaining people: the role of research

Crescimento de Bertholletia excelsa em floresta natural em Juína, MT.

Resumo

A self-consistent kinetic model for droplet heating and evaporation

A new kinetic model for heating and evaporation of Diesel fuel droplets is suggested. The model is based on the introduction of the kinetic region in the immediate vicinity of the heated and evaporating droplets, where the dynamics of molecules are described in terms of the Boltzmann equations for vapour components and air, and the hydrodynamic region. The effects of finite thermal conductivity and species diffusivity inside the droplets and inelastic collisions in the kinetic region are taken into account. Diesel fuel is approximated by n-dodecane or a mixture of 80% n-dodecane and 20% p-dipropylbenzene. In both cases, the evaporation coefficient is assumed equal to 1. The values of temperature and vapour density at the outer boundary of the kinetic region are inferred from the requirement that both heat flux and mass flux of vapour (or vapour components) in the kinetic and hydrodynamic regions in the vicinity of the interface between these regions should be equal. Initially, the heat and mass fluxes in the hydrodynamic region are calculated based on the values of temperature and vapour density at the surface of the droplet. Then the values of temperature and vapour density at the outer boundary of the kinetic region, obtained following the above-mentioned procedure, are used to calculate the corrected values of hydrodynamic heat and mass fluxes. The latter in their turn lead to new corrected values of temperature and vapour density at the outer boundary of the kinetic region etc. It is shown that this process quickly converges for the cases analysed in the paper, and it leads to self-consistent values for both heat and mass fluxes. The model is applied to the analysis of heating and evaporation of Diesel fuel droplets with initial radii and temperature equal to 5 μm and 300 K, immersed into gas with temperatures in the range 800–1200 K and pressure equal to 30 bar. It is shown that in all cases the kinetic effects lead to a decrease in droplet surface temperature and an increase in the evaporation time. The kinetic effects on the droplet evaporation time are shown to increase with increasing gas temperatures. Publisher statement: NOTICE: this is the author’s version of a work that was accepted for publication in International Journal of Heat and Mass Transfer. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Heat and Mass Transfer, [79, (2015)] DOI: 10.1016/j.ijheatmasstransfer.2015.10.039 © 2015, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0

Qualidade do eucalipto clone h13 em sistemas integrados de produção de leite

Um dos grandes desafios nacionais, atualmente, é transformar áreas degradadas em áreas produtivas com a introdução de árvores em sistemas agropecuários como a integração lavoura pecuária floresta (iLPF) ou sistemas agrossilvipastoris. A presença de árvores em sistemas agropecuários pode proporcionar vários benefícios como a melhoria nos índices de conforto térmico animal, aumento na oferta de forragem ao longo do ano, redução da erosão, otimização do uso da energia solar e da ciclagem de nutrientes. Entretanto, ainda existem poucas informações em relação à qualidade do fuste em sistemas iLPF, que são fundamentais para acessar o mercado de madeira serrada, que propicia maior valor agregado e maiores taxas de retorno aos produtores. Com isso, objetivou-se avaliar a qualidade do fuste, fitossanidade e as características das árvores do clone de híbrido Eucaliptus grandis x Eucalyptus urophylla (clone H13) em sistema iLPF. O experimento foi instalado em blocos casualizados, com quatro repetições e dois tratamentos (1) R3: arranjo em renques triplos com espaçamento 3 x 2 entre árvores e 15 m entre renques de árvores (2) R2: renques duplos com espaçamento 3 x 2 m entre árvores e 50 m entre renques de árvores. O experimento está localizado no campo experimental da Embrapa Agrossilvipastoril, localizada no município de Sinop- MT, situado na região de transição dos biomas Cerrado e Floresta Amazônia. As avaliações da qualidade das árvores de eucalipto em sistema integrado foram realizadas aos 36 meses do plantio, durante a estação seca do ano, mediante observação visual qualidade do fuste (tortuosidade, bifurcações e posição da mesma), fitossanidade (pragas e doenças) e as características (copa, galhos e tronco quebrados, mortalidade, inclinação, e multibrotação das copas) das árvores. A qualidade do fuste encontra-se, em algum grau, comprometida em 68% e 74%, respectivamente, nos arranjos R2 e R3, sendo 55% e 65% da tortuosidade localizado na região apical da planta. No R2, 88% das árvores apresentou a fitossanidade comprometida por bovinos, sendo que 57% atingindo o lenho em mais de 5 cm. O arranjo R3 possui os mesmos danos, causados por bovinos, em 94% das árvores onde 53% são os mais severos com mais de 5cm do lenho exposto. Das características avaliadas, houve maior ocorrência em mortalidade das árvores no R3 com 65% e no R2 com 42%. O arranjo R2 mostrou-se mais vulnerável à quebra de copa com 13% e galhos também com 13%, quando comparado com o arranjo R3 que teve somente 5% das copas quebradas e 3% dos galhos

The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies

Using the stellar kinematic maps and ancillary imaging data from the Sydney AAO Multi Integral field (SAMI) Galaxy Survey, the intrinsic shape of kinematically-selected samples of galaxies is inferred. We implement an efficient and optimised algorithm to fit the intrinsic shape of galaxies using an established method to simultaneously invert the distributions of apparent ellipticities and kinematic misalignments. The algorithm output compares favourably with previous studies of the intrinsic shape of galaxies based on imaging alone and our re-analysis of the ATLAS3D data. Our results indicate that most galaxies are oblate axisymmetric. We show empirically that the intrinsic shape of galaxies varies as a function of their rotational support as measured by the "spin" parameter proxy Lambda_Re. In particular, low spin systems have a higher occurrence of triaxiality, while high spin systems are more intrinsically flattened and axisymmetric. The intrinsic shape of galaxies is linked to their formation and merger histories. Galaxies with high spin values have intrinsic shapes consistent with dissipational minor mergers, while the intrinsic shape of low-spin systems is consistent with dissipationless multi-merger assembly histories. This range in assembly histories inferred from intrinsic shapes is broadly consistent with expectations from cosmological simulations.Comment: 15 pages, 11 figures, MNRAS in prin

The low dimensional dynamical system approach in General Relativity: an example

In this paper we explore one of the most important features of the Galerkin method, which is to achieve high accuracy with a relatively modest computational effort, in the dynamics of Robinson-Trautman spacetimes.Comment: 7 pages, 5 figure

The SAMI Galaxy Survey: The Low-Redshift Stellar Mass Tully-Fisher Relation

We investigate the Tully-Fisher Relation (TFR) for a morphologically and kine- matically diverse sample of galaxies from the SAMI Galaxy Survey using 2 dimensional spatially resolved Halpha velocity maps and find a well defined relation across the stellar mass range of 8.0 < log(M*) < 11.5. We use an adaptation of kinemetry to parametrise the kinematic Halpha asymmetry of all galaxies in the sample, and find a correlation between scatter (i.e. residuals off the TFR) and asymmetry. This effect is pronounced at low stellar mass, corresponding to the inverse relationship between stellar mass and kinematic asymmetry found in previous work. For galaxies with log(M*) < 9.5, 25 +/- 3% are scattered below the root mean square (RMS) of the TFR, whereas for galaxies with log(M*) > 9.5 the fraction is 10 +/- 1% We use 'simulated slits' to directly compare our results with those from long slit spectroscopy and find that aligning slits with the photometric, rather than the kinematic, position angle, increases global scatter below the TFR. Further, kinematic asymmetry is correlated with misalignment between the photometric and kinematic position angles. This work demonstrates the value of 2D spatially resolved kinematics for accurate TFR studies; integral field spectroscopy reduces the underestimation of rotation velocity that can occur from slit positioning off the kinematic axis

The SAMI Galaxy Survey: Revising the Fraction of Slow Rotators in IFS Galaxy Surveys

The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities $V/\sigma$ and $\lambda_{R}$. Our demonstration involves integral field data from the SAMI Galaxy Survey and the ATLAS$^{\rm{3D}}$ Survey. We find a tight relation for both $V/\sigma$ and $\lambda_{R}$ when measured in different apertures that can be used as a linear transformation as a function of radius, i.e., a first-order aperture correction. We find that $V/\sigma$ and $\lambda_{R}$ radial growth curves are well approximated by second order polynomials. By only fitting the inner profile (0.5$R_{\rm{e}}$), we successfully recover the profile out to one $R_{\rm{e}}$ if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for $V/\sigma$ and $\lambda_{R}$ derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected $\lambda_{R}$ measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with $\log M_{*}/M_{\odot}>$ 11, the fraction of slow rotators is $35.9\pm4.3$ percent, but is underestimated if galaxies without coverage beyond one $R_{\rm{e}}$ are not included in the sample ($24.2\pm5.3$ percent). With measurements out to the largest aperture radius the slow rotator fraction is similar as compared to using aperture corrected values ($38.3\pm4.4$ percent). Thus, aperture effects can significantly bias stellar kinematic IFS studies, but this bias can now be removed with the method outlined here.Comment: Accepted for Publication in the Monthly Notices of the Royal Astronomical Society. 16 pages and 11 figures. The key figures of the paper are: 1, 4, 9, and 1