862 research outputs found

    Molecular Gas, Dust and Star Formation in Galaxies: II. Dust properties and scalings in \sim\ 1600 nearby galaxies

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    We aim to characterize the relationship between dust properties. We also aim to provide equations to estimate accurate dust properties from limited observational datasets. We assemble a sample of 1,630 nearby (z<0.1) galaxies-over a large range of Mstar, SFR - with multi-wavelength observations available from wise, iras, planck and/or SCUBA. The characterization of dust emission comes from SED fitting using Draine & Li dust models, which we parametrize using two components (warm and cold ). The subsample of these galaxies with global measurements of CO and/or HI are used to explore the molecular and/or atomic gas content of the galaxies. The total Lir, Mdust and dust temperature of the cold component (Tc) form a plane that we refer to as the dust plane. A galaxy's sSFR drives its position on the dust plane: starburst galaxies show higher Lir, Mdust and Tc compared to Main Sequence and passive galaxies. Starburst galaxies also show higher specific Mdust (Mdust/Mstar) and specific Mgas (Mgas/Mstar). The Mdust is more closely correlated with the total Mgas (atomic plus molecular) than with the individual components. Our multi wavelength data allows us to define several equations to estimate Lir, Mdust and Tc from one or two monochromatic luminosities in the infrared and/or sub-millimeter. We estimate the dust mass and infrared luminosity from a single monochromatic luminosity within the R-J tail of the dust emission, with errors of 0.12 and 0.20dex, respectively. These errors are reduced to 0.05 and 0.10 dex, respectively, if the Tc is used. The Mdust is correlated with the total Mism (Mism \propto Mdust^0.7). For galaxies with Mstar 8.5<log(Mstar/Msun) < 11.9, the conversion factor \alpha_850mum shows a large scatter (rms=0.29dex). The SF mode of a galaxy shows a correlation with both the Mgass and Mdust: high Mdust/Mstar galaxies are gas-rich and show the highest SFRs.Comment: 24 pages, 28 figures, 6 tables, Accepted for publication in A&

    Avaliações da subtração dos elementos N, P e K sobre a produção e qualidade de frutos de amoreira-preta.

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    Investigating evidence for different black hole accretion modes since redshift z~1

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    Chandra data in the COSMOS, AEGIS-XD and 4Ms CDFS are combined with optical/near-IR photometry to determine the rest-frame U-V vs V-J colours of X-ray AGN hosts at mean redshifts 0.40 and 0.85. This combination of colours (UVJ) provides an efficient means of separating quiescent from star-forming, including dust reddened, galaxies. Morphological information emphasises differences between AGN split by their UVJ colours. AGN in quiescent galaxies are dominated by spheroids, while star-forming hosts are split between bulges and disks. The UVJ diagram of AGN hosts is then used to set limits on the accretion density associated with evolved and star-forming systems. Most of the black hole growth since z~1 is associated with star-forming hosts. Nevertheless, ~15-20% of the X-ray luminosity density since z~1, is taking place in the quiescent region of the UVJ diagram. For the z~0.40 subsample, there is tentative evidence (2sigma significance), that AGN split by their UVJ colours differ in Eddington ratio. AGN in star-forming hosts dominate at high Eddington ratios, while AGN in quiescent hosts become increasingly important as a fraction of the total population toward low Eddington ratios. At higher redshift, z~0.8, such differences are significant at the 2sigma level only at Eddington ratios >1e-3. These findings are consistent with scenarios in which diverse accretion modes are responsible for the build-up of SMBHs at the centres of galaxies. We compare our results with the GALFORM semi-analytic model, which postulates two black hole fuelling modes, the first linked to star-formation and the second occuring in passive galaxies. GALFORM predicts a larger fraction of black hole growth in quiescent galaxies at z<1, compared to the data. Relaxing the strong assumption of the model that passive AGN hosts have zero star-formation rate could reconcile this disagreement.Comment: MNRAS accepte

    Definição da posição da folha de pimenta longa para avaliação do estado nutricional.

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    Foram avaliadas quatro posições de amostragem de folhas de pimenta longa para fins de definição da amostragem mais adequados em estudos de nutrição de plantas desta espécie, visando subsidiar pesquisas com sua domesticação. Folhas completamente expandidas de vinte plantas de diferentes parcelas experimentais de um experimento, que receberam mesma adubação anual, foram amostradas, nas posições, do ápice para a base do galho: P1- primeira folha, P2 – segunda folha, P3 - terceira folha e P4, quarta folha, tomando-se, vinte amostras por parcela, as quais foram depois reunidas em uma amostra composta por parcela As folhas foram avaliadas para os teores de macro e micronutrientes. Foram comparadas médias e variabilidade entre as diferentes posições, com base nos teores foliares e índices DRIS multivariados. Para a maioria dos nutrientes avaliados não houve efeito da posição de amostragem, sendo que na posição P1, houve maior concordância entre o estado nutricional determinado pelo DRIS e pelo método convencional, além de menor variabilidade amostral, sendo esta a posição de amostragem indicada

    Indicadores ecotoxicológicos para águas de consumo humano.

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    Testes de toxicidade utilizando organismos vivos, são de alta vantagem em termos de custo e benefício. Mostram com rapidez a qualidade das amostras testadas quanto a toxicidade. Utiliza-se organismos padronizados, de vários níveis tróficos, os quais respondem de maneira diversa aos diversos componentes das amostras ambientais. A qualidade de águas tratadas por ETAs das cidades de Limeira e Piracicaba, SP, foram avaliadas quanto a toxicidade para o microcrustáceo Daphnia magna, celenterado Hydra attenuata, alga Pseudokirchneriella subcapitata e a bactéria Vibrio fischeri . As Daphnias e as algas mostraram se altamente sensíveis a cloração, as Hydras e Vibrio mostraram-se resistentes sendo possível ser realizados testes com águas tratadas e cloradas. O tiossulfato de sódio foi utilizado para precipitar o cloro das amostras cloradas, entretanto precipitou também outras substâncias, diminuindo a toxicidade das águas brutas, sem cloro. Análises de resíduos mostrou a presença de herbicidas e trihalometanos nas amostras de água tratada do rio Corumbataí. O crescimento da alga P.subcapitata foi inibido em concentrações de atrazina de 7 a 10 microgramas L-1, mas não de 3 a 3,7 microgramas g L-1 . Os testes toxicológicos são importantes ferramentas para indicar presença de compostos tóxicos em amostras de água e podem mostrar a qualidade das águas tratadas

    Optical, near-IR and sub-mm IFU Observations of the nearby dual AGN Mrk 463

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    We present optical and near-IR Integral Field Unit (IFU) and ALMA band 6 observations of the nearby dual Active Galactic Nuclei (AGN) Mrk 463. At a distance of 210 Mpc, and a nuclear separation of \sim4 kpc, Mrk 463 is an excellent laboratory to study the gas dynamics, star formation processes and supermassive black hole (SMBH) accretion in a late-stage gas-rich major galaxy merger. The IFU observations reveal a complex morphology, including tidal tails, star-forming clumps, and emission line regions. The optical data, which map the full extent of the merger, show evidence for a biconical outflow and material outflowing at >>600 km s1^{-1}, both associated with the Mrk 463E nucleus, together with large scale gradients likely related to the ongoing galaxy merger. We further find an emission line region \sim11 kpc south of Mrk 463E that is consistent with being photoionized by an AGN. Compared to the current AGN luminosity, the energy budget of the cloud implies a luminosity drop in Mrk 463E by a factor 3-20 over the last 40,000 years. The ALMA observations of 12^{12}CO(2-1) and adjacent 1mm continuum reveal the presence of \sim109^{9}M_\odot in molecular gas in the system. The molecular gas shows velocity gradients of \sim800 km/s and \sim400 km/s around the Mrk 463E and 463W nuclei, respectively. We conclude that in this system the infall of \sim100s MM_\odot/yr of molecular gas is in rough balance with the removal of ionized gas by a biconical outflow being fueled by a relatively small, <<0.01% of accretion onto each SMBH.Comment: Accepted by The Astrophysical Journal, 23 pages, 19 figure
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