Disk galaxy scaling relations at intermediate redshifts - I. The Tully-Fisher and velocity-size relations

We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z~1 using the FORS instruments of the ESO Very Large Telescope. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the 2-D spectra. Taking into account all geometrical, observational and instrumental effects, these rotation curves were used to derive the intrinsic Vmax. Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax could be robustly determined for 124 galaxies covering redshifts 0.05<z<0.97. This is one of the largest kinematic samples of distant disk galaxies to date. We compared this data set to the local B-band Tully-Fisher relation and the local velocity-size relation. The scatter in both scaling relations is a factor of ~2 larger at z~0.5 than at z~0. The deviations of individual distant galaxies from the local Tully-Fisher relation are systematic in the sense that the galaxies are increasingly overluminous towards higher redshifts, corresponding to an over-luminosity of -(1.2+-0.5) mag at z=1. This luminosity evolution at given Vmax is probably driven by younger stellar populations of distant galaxies with respect to their local counterparts, potentially combined with modest changes in dark matter mass fractions. The analysis of the velocity-size relation reveals that disk galaxies of a given Vmax have grown in size by a factor of ~1.5 over the past ~8 Gyr, likely via accretion of cold gas and/or small satellites. Scrutinizing the combined evolution in luminosity and size, we find that the galaxies which show the strongest evolution towards smaller sizes at z~1 are not those which feature the strongest evolution in luminosity, and vice versa. [abstract abbreviated]Comment: A&A, accepted. 12 pages, 6 figures, 1 tabl

Disk galaxy scaling relations at intermediate redshifts - I. The Tully-Fisher and velocity-size relations

We took spatially resolved slit spectra of 261 field disk galaxies at redshifts up to z~1 using the FORS instruments of the ESO Very Large Telescope. Our spectroscopy was complemented with HST/ACS imaging in the F814W filter. We analyzed the ionized gas kinematics by extracting rotation curves from the 2-D spectra. Taking into account all geometrical, observational and instrumental effects, these rotation curves were used to derive the intrinsic Vmax. Neglecting galaxies with disturbed kinematics or insufficient spatial rotation curve extent, Vmax could be robustly determined for 124 galaxies covering redshifts 0.05<z<0.97. This is one of the largest kinematic samples of distant disk galaxies to date. We compared this data set to the local B-band Tully-Fisher relation and the local velocity-size relation. The scatter in both scaling relations is a factor of ~2 larger at z~0.5 than at z~0. The deviations of individual distant galaxies from the local Tully-Fisher relation are systematic in the sense that the galaxies are increasingly overluminous towards higher redshifts, corresponding to an over-luminosity of -(1.2+-0.5) mag at z=1. This luminosity evolution at given Vmax is probably driven by younger stellar populations of distant galaxies with respect to their local counterparts, potentially combined with modest changes in dark matter mass fractions. The analysis of the velocity-size relation reveals that disk galaxies of a given Vmax have grown in size by a factor of ~1.5 over the past ~8 Gyr, likely via accretion of cold gas and/or small satellites. Scrutinizing the combined evolution in luminosity and size, we find that the galaxies which show the strongest evolution towards smaller sizes at z~1 are not those which feature the strongest evolution in luminosity, and vice versa. [abstract abbreviated]Comment: A&A, accepted. 12 pages, 6 figures, 1 tabl

Reação de algumas culturas de cobertura utilizadas no sistema plantio direto ao nematóide reniforme.

bitstream/item/24693/1/COT200599.pd

Avaliação quali-quantitativa da ocorrência de nematóides fitoparasitos em regiões de produção de algodão de Mato Grosso do Sul.

Nos anos agrícolas de 2001/02 e 2002/03 foram amostrados 184 talhões de lavouras de algodoeiro dos municípios de Aral Moreira, Chapadão do Sul, Costa Rica, Deodápolis, Dois Irmãos do Buriti, Eldorado, Guia Lopes da Laguna, Itaquiraí, Maracaju, Mundo Novo, Naviraí, Nioaque, Pedro Gomes, Ponta Porã, São Gabriel do Oeste e Sidrolândia. Cada amostra, composta de 10 subamostras de solo tomadas à profundidade de 0-20 cm, representou glebas ou talhões de aproximadamente 100 hectares, exceção feita às amostras de pequenas propriedades (<100 ha). As amostras foram embaladas em sacos plásticos, armazenadas em caixas de isopor e levadas ao laboratório de Nematologia da Embrapa Agropecuária Oeste. No laboratório, foram realizadas a extração, identificação e quantificação dos nematóides presentes. Os resultados obtidos indicaram haver grande variabilidade na distribuição dos nematóides fitoparasitas nas diferentes lavouras amostradas. Meloidogyne incognita foi encontrado em 27,7% das amostras analisadas; Rotylenchulus reniformis em 16,8% e Pratylenchus brachyurus em 65,2%. A ocorrência de populações mistas de nematóides foi inferior a de populações simples. M. incognita e R. reniformis ocorreram acima dos níveis populacionais de danos em, respectivamente, 45,0% e 32,3% das amostras. Em termos médios, a freqüência de ocorrência de nematóides fitoparasitos foi maior em regiões com predominância de pequenas propriedades, onde constatou-se também um número superior de amostras com populações acima dos níveis de danos. Avaliação Quali-quantitativa da Ocorrência de Nematóides Fitoparasitos em Regiões de Produção de Algodão de Mato Grosso do Sul 6bitstream/item/38770/1/BP200315.pdfDocumento online

Evolution of field spiral galaxies up to redshifts z=1

We have gained VLT/FORS spectra and HST/ACS images of a sample of 220 distant field spiral galaxies. Spatially resolved rotation curves were extracted and fitted with synthetic velocity fields that take into account all geometric and observational effects, like blurring due to the slit width and seeing influence. The maximum rotation velocity Vmax could be determined for 124 galaxies that cover the redshift range 0.1<z<1.0. The luminosity-rotation velocity distribution of this sample is offset from the Tully-Fisher relation (TFR) of local low-mass spirals, whereas the distant high-mass spirals are compatible with the local TFR. We show that the slope of the local and the intermediate-z TFR would be in compliance if its scatter decreased by more than a factor of 3 between z~0.5 and z~0. On the other hand, the distant low-luminosity disks have much lower stellar M/L ratios than their local counterparts, while high-luminosity disks barely evolved in M/L over the covered redshift range. This could be the manifestation of the "downsizing" effect, i.e. the succesive shift of the peak of star formation from high-mass to low-mass galaxies towards lower redshifts. This trend might be canceled out in the TF diagram due to the simultaneous evolution of multiple parameters. We also estimate the ratios between stellar and total masses, finding that these remained constant since z=1, as would be expected in the context of hierarchically growing structure. (Abridged)Comment: 20 pages, 5 figures, ApJ, accepte

Rotação de culturas para o manejo do nematoide reniforme em algodoeiro.

bitstream/item/24264/1/BP201055.pdfDocumento on-line

Disk galaxy evolution up to redshift z=1

We have performed intermediate-resolution VLT/FORS spectroscopy and HST/ACS imaging of 129 field spiral galaxies within the FORS Deep Field. The galaxies cover the redshift range 0.1 < z < 1.0 and comprise all types from Sa to Sdm/Im. Spatially resolved rotation curves were extracted and fitted with synthetic velocity fields that take into account all geometric (e.g., inclination and misalignment) and observational effects (in particular, blurring due to optical beam smearing and seeing). Using these fits, the maximum rotation velocity Vmax could be determined for 73 objects. The Tully-Fisher relation of this sample at a mean look-back time of ~5Gyr shows a luminosity evolution which amounts to ~2mag in rest-frame B for low-mass spirals (Vmax~100km/s) but is negligible for high-mass spirals (Vmax~300km/s). This confirms our previous analysis which was limited to ground-based imaging. The observed overluminosity of low-mass galaxies is at variance with predictions from simulations. On the other hand, at given Vmax, we find slightly smaller disk sizes towards higher redshifts, in compliance with the CDM hierarchical model. The observed mass-dependent luminosity evolution might therefore point towards the need for a more realistic modelling of the stellar (i.e. baryonic) component in N-body codes.Comment: 4 pages, 2 figures. To appear in the Proceedings of Science (published by SISSA), Conference "Baryons in Dark Matter Haloes", Novigrad, Croatia, 5-9 October 200