Uncertainties in gas kinematics arising from stellar continuum modelling in integral field spectroscopy data: the case of NGC2906 observed with MUSE/VLT

We study how the use of several stellar subtraction methods and line fitting approaches can affect the derivation of the main kinematic parameters (velocity and velocity dispersion fields) of the ionized gas component. The target of this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at Very Large Telescope. A sample of twelve spectra is selected from the inner (nucleus) and outer (spiral arms) regions, characterized by different ionization mechanisms. We compare three different methods to subtract the stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the following stellar libraries: MILES, STELIB and GRANADA+MILES. The choice of the stellar subtraction method is the most important ingredient affecting the derivation of the gas kinematics, followed by the choice of the stellar library and by the line fitting approach. In our data, typical uncertainties in the observed wavelength and width of the H\alpha and [NII] lines are of the order of _rms \sim 0.1\AA\ and _rms \sim 0.2\AA\ (\sim 5 and 10km/s, respectively). The results obtained from the [NII] line seem to be slightly more robust, as it is less affected by stellar absorption than H\alpha. All methods considered yield statistically consistent measurements once a mean systemic contribution \Delta\bar\lambda=\Delta\bar\sigma=0.2xDelta_{MUSE} is added in quadrature to the line fitting errors, where \Delta_{MUSE} = 1.1\AA\ \sim 50 km/s denotes the instrumental resolution of the MUSE spectra. Although the subtraction of the stellar continuum is critical in order to recover line fluxes, any method (including none) can be used in order to measure the gas kinematics, as long as an additional component of 0.2 x Delta_MUSE is added to the error budget.Comment: 20 pages, 14 figure

Los insectos comestibles: un recurso para el desarrollo local en el centro de México

Los insectos comestibles forman parte de los hábitos tradicionales de alimentación de México y el mundo, su preparación y consumo ha permanecido prácticamente igual durante siglos, pero en la actualidad, se observan cambios radicales debido, entre otras cosas a que se piensa que lo que cuenta es la cosmética de los alimentos de una manera predominante por lo cual se ha dejado de lado, además, con estos recursos naturales silvestres se tiene la posibilidad de iniciar grandes negocios al ser clasificados según el punto de vista occidental como “Alimentos exóticos”. La modificación de la apariencia y a la vez la conservación del valor cultural y el reconocimiento de la territorialidad de un producto, son factores de peso que permitirán la subsistencia y posterior aprovechamiento de los recursos naturales de las regiones. Tal es el caso del Escamol (huevos de hormiga- Liometopum apiculatum), insecto endémico de las inmediaciones de la cuenca de México, con el cual se pretende establecer las bases de reproducción -no en cautiverio- de una especie con gran demanda en el mercado gastronómico y que al paso del tiempo impulsará el desarrollo local de las regiones donde se produzca.Insectos comestibles, Teotihuacán, México, desarrollo local, tradiciones, escamoles., Agribusiness, Agricultural and Food Policy, Community/Rural/Urban Development, Food Consumption/Nutrition/Food Safety, Labor and Human Capital,

INDICADORES DEMOGRÁFICOS, DE MERCADO LABORAL E INFRAESTRUCTURAS. LÍNEAS DE DESARROLLO.

São apresentados indicadores desenvolvidos no âmbito do projeto OTALEX C, relativos à Sustentabilidade Territorial, mais concretamente com a acessibilidade espacial, designadamente indicadores de acesso em tempos mínimos a serviços básicos sanitários (centros de saúde, hospitais, residências de idosos e centros de dia) e educativos (escolas, estabelecimentos de ensino secundário e superior), bem como a núcleos de população de hierarquia superior (cidades com mais de 20000, 50000 e 200000 habitantes). Estes indicadores serão incorporados à bateria de indicadores de sustentabilidade do projeto OTALEX C

Helical bilayer nonbenzenoid nanographene bearing a [10]helicene with two embedded heptagons

The precision synthesis of helical bilayer nanographenes (NGs) with new topology is of substantial interest because of their exotic physicochemical properties. However, helical bilayer NGs bearing non-hexagonal rings remain synthetically challenging. Here we present the efficient synthesis of the first helical bilayer nonbenzenoid nanographene (HBNG1) from a tailor-made azulene-embedded precursor, which contains a novel [10]helicene backbone with two embedded heptagons. Single-crystal X-ray analysis reveals its highly twisted bilayer geometry with a record small interlayer distance of 3.2 Å among the reported helical bilayer NGs. Notably, the close interlayer distance between the two layers offers intramolecular through-space conjugation as revealed by in situ spectroelectrochemistry studies together with DFT simulations. Furthermore, the chiroptical properties of the P/M enantiomers of HBNG1 are also evaluated by circular dichroism and circularly polarized luminescence

Field spheroid-dominated galaxies in a Λ-CDM Universe

Context. Understanding the formation and evolution of early-type, spheroid-dominated galaxies is an open question within the context of the hierarchical clustering scenario, particularly in low-density environments. Aims. Our goal is to study the main structural, dynamical, and stellar population properties and assembly histories of field spheroid-dominated galaxies formed in a Λ-cold dark matter (Λ-CDM) scenario to assess to what extent they are consistent with observations. Methods. We selected spheroid-dominated systems from a Λ-CDM simulation that includes star formation (SF), chemical evolution, and supernova feedback. The sample is made up of 18 field systems with MStar ≤ 6 × 1010M⊙ that are dominated by the spheroid component. For this sample we estimated the fundamental relations of ellipticals and compared them with current observations. Results. The simulated spheroid galaxies have sizes that are in good agreement with observations. The bulges follow a Sersic law with Sersic indexes that correlate with the bulge-to-total mass ratios. The structural-dynamical properties of the simulated galaxies are consistent with observed Faber-Jackson, fundamental plane, and Tully-Fisher relations. However, the simulated galaxies are bluer and with higher star formation rates (SFRs) than the observed isolated early-type galaxies. The archaeological mass growth histories show a slightly delayed formation and more prominent inside-out growth mode than observational inferences based on the fossil record method. Conclusions. The main structural and dynamical properties of the simulated spheroid-dominated galaxies are consistent with observations. This is remarkable since our simulation has not been calibrated to match them. However, the simulated galaxies are blue and star-forming, and with later stellar mass growth histories compared to observational inferences. This is mainly due to the persistence of extended discs in the simulations. The need for more efficient quenching mechanisms able to avoid further disc growth and SF is required in order to reproduce current observational trends.Fil: Rosito, María Sol. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Pedrosa, Susana Elizabeth. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Tissera, Patricia Beatriz. Universidad Andrés Bello; ChileFil: Avila Reese, Vladimir. Universidad Nacional Autónoma de México; MéxicoFil: Lacerna, I.. Universidad Católica de Chile; ChileFil: Bignone, Lucas Axel. Pontificia Universidad Católica de Chile; ChileFil: Ibarra-Medel, H.J.. Universidad Andrés Bello; ChileFil: Varela, S.. Universidad Andrés Bello; Chil