The Baryon Cycle at High Redshifts: Effects of Galactic Winds on Galaxy Evolution in Overdense and Average Regions

We employ high-resolution cosmological zoom-in simulations focusing on a high-sigma peak and an average cosmological field at $z\sim 6-12$, in order to investigate the influence of environment and baryonic feedback on galaxy evolution in the reionization epoch. Strong feedback, e.g., galactic winds, caused by elevated star formation rates (SFRs) is expected to play an important role in this evolution. We compare different outflow prescriptions: (i) constant wind velocity (CW), (ii) variable wind scaling with galaxy properties (VW), and (iii) no outflows (NW). The overdensity leads to accelerated evolution of dark matter and baryonic structures, absent in the "normal" region, and to shallow galaxy stellar mass functions at the low-mass end. Although CW shows little dependence on both environments, the more physically motivated VW model does exhibit this effect. In addition, VW can reproduce the observed specific SFR (sSFR) and the sSFR-stellar mass relation, which CW and NW fail to satisfy simultaneously. Winds also differ substantially in affecting the state of the intergalactic medium (IGM). The difference lies in volume-filling factor of hot, high-metallicity gas which is near unity for CW, while it remains confined in massive filaments for VW, and locked up in galaxies for NW. Such gas is nearly absent in the normal region. Although all wind models suffer from deficiencies, the VW model seems to be promising in correlating the outflow properties to those of host galaxies. Further constraints on the state of the IGM at high-$z$ are needed to separate different wind models.Comment: 22 pages, 15 figures, accepted for publication in the Astrophysical Journa

Effect of dark matter halo substructures on galaxy rotation curves

The effect of halo substructures on galaxy rotation curves is investigated in this paper using a simple model of dark matter clustering. A dark matter halo density profile is developed based only on the scale free nature of clustering that leads to a statistically self-similar distribution of the substructures at galactic scale. Semi-analytical method is used to derive rotation curves for such a clumpy dark matter density profile. It is found that the halo substructures significantly affect the galaxy velocity field. Based on the fractal geometry of the halo, this self-consistent model predicts an NFW-like rotation curve and a scale free power spectrum of the rotation velocity fluctuations.Comment: 6 pages, 3 figures. Accepted for publication in ApJ. The definitive version will be available at http://iopscience.iop.org

Andalusia, from Peripheral Urbanism to Real-State Bubble. Hiperdevelopment of Real-State Sector as Sign of Underdevelopment

Andalucía ha sido históricamente una de las típicas periferias internas del capitalismo europeo. El presente artículo pretende plantear la actualidad de esta situación cambiando el foco tradicional sobre el problema andaluz, desde la cuestión agraria a la producción del espacio urbano. Se discuten para ello algunos aspectos del cuerpo teórico desarrollado en torno al concepto de urbanismo periférico, así como la teoría del segundo circuito de acumulación de capital de Henri Lefebvre y David Harvey. Las teorías se contrastan con el caso andaluz, construido a partir de fuentes secundarias y de datos de la estadística pública sobre estructura social y económica. Finalmente, se concluye que en la transición de un modelo agro-exportador a un modelo basado en el binomio formado por el sector turístico y la especulación inmobiliario-financiera, Andalucía continúa en una situación periférica y subordinada.Andalusia has been historically a peripheral area within European capitalism. This paper aims to present the actuality of this situation changing the usual focus, from the study of rural issues to the production of space. In order to do this, some theoretical aspects regarding peripheral urbanism and the theory of the second circuit of capital accumulation of Henry Lefebvre and David Harvey will be discussed. These models will be compared with the case of Andalusia, considering secondary sources and public statistics data about social and economic structure. Finally, the paper concludes that in the transition from a commodity-export pattern to another one based in the articulation between tourism and real-estate bubble, Andalusia retains its position as a peripheral and subordinated area

Disk Evolution and Bar Triggering Driven by Interactions with Dark Matter Substructure

We study formation and evolution of bar-disk systems in fully self-consistent cosmological simulations of galaxy formation in the LCDM WMAP3 Universe. In a representative model we find that the first generation of bars form in response to the asymmetric dark matter (DM) distribution (i.e., DM filament) and quickly decay. Subsequent bar generations form and are destroyed during the major merger epoch permeated by interactions with a DM substructure (subhalos). A long-lived bar is triggered by a tide from a subhalo and survives for ~10 Gyr. The evolution of this bar is followed during the subsequent numerous minor mergers and interactions with the substructure. Together with intrinsic factors, these interactions largely determine the stellar bar evolution. The bar strength and its pattern speed anticorrelate, except during interactions and when the secondary (nuclear) bar is present. For about 5 Gyr bar pattern speed increases substantially despite the loss of angular momentum to stars and cuspy DM halo. We analyze the evolution of stellar populations in the bar-disk and relate them to the underlying dynamics. While the bar is made mainly of an intermediate age, ~5-6 Gyr, disk stars at z=0, a secondary nuclear bar which surfaces at z~0.1 is made of younger, ~1-3 Gyr stars.Comment: 5 pages, 5 figures, accepted for publication in ApJ Letter

Dissecting Galaxy Formation: II. Comparing Substructure in Pure Dark Matter and Baryonic Models

We compare the substructure evolution in pure dark matter (DM) halos with those in the presence of baryons (PDM and BDM). The prime halos have been analyzed by Romano-Diaz et al (2009). Models have been evolved from identical initial conditions using Constrained Realizations, including star formation and feedback. A comprehensive catalog of subhalos has been compiled and properties of subhalos analyzed in the mass range of 10^8 Mo - 10^11 Mo. We find that subhalo mass functions are consistent with a single power law, M_sbh^{alpha}, but detect a nonnegligible shift between these functions, alpha -0.86 for the PDM, and -0.98 for the BDM. Overall, alpha const. in time with variations of +-15%. Second, we find that the radial mass distribution of subhalos can be approximated by a power law, R^{gamma} with a steepening around the radius of a maximal circular velocity, Rvmax, in the prime halos. Gamma ~-1.5 for the PDM and -1 for the BDM, inside Rvmax, and is steeper outside. We detect little spatial bias between the subhalo populations and the DM of the main halos. The subhalo population exhibits much less triaxiality with baryons, in tandem with the prime halo. Finally, we find that, counter-intuitively, the BDM population is depleted at a faster rate than the PDM one within the central 30kpc of the prime. Although the baryons provide a substantial glue to the subhalos, the main halos exhibit the same trend. This assures a more efficient tidal disruption of the BDM subhalos. This effect can be reversed for a more efficient feedback from stellar evolution and supermassive black holes, which will expel baryons from the center and decrease the concentration of the prime halo. We compare our results with via Lactea and Aquarius simulations and other published results.Comment: 12 pages, 9 figures, to be published by the Astrophysical Journa

The Dark Side of QSO Formation at High Redshifts

Observed high-redshift QSOs, at z ~ 6, may reside in massive dark matter (DM) halos of more than 1012 M☉ and are thus expected to be surrounded by overdense regions. In a series of 10 constrained simulations, we have tested the environment of such QSOs. The usage of constrained realizations has enabled us to address the issue of cosmic variance and to study the statistical properties of the QSO host halos. Comparing the computed overdensities with respect to the unconstrained simulations of regions empty of QSOs, assuming there is no bias between the DM and baryon distributions, and invoking an observationally constrained duty cycle for Lyman break galaxies, we have obtained the galaxy count number for the QSO environment. We find that a clear discrepancy exists between the computed and observed galaxy counts in the Kim et al. samples. Our simulations predict that on average eight z ~ 6 galaxies per QSO field should have been observed, while Kim et al. detect on average four galaxies per QSO field compared to an average of three galaxies in a control sample (GOODS fields). While we cannot rule out a small number of statistics for the observed fields to high confidence, the discrepancy suggests that galaxy formation in the QSO neighborhood proceeds differently than in the field. We also find that QSO halos are the most massive of the simulated volume at z ~ 6 but this is no longer true at z ~ 3. This implies that QSO halos, even in a case where they are the most massive ones at high redshifts, do not evolve into the most massive galaxy clusters at z = 0

Software support for multitouch interaction: the end-user programming perspective

Empowering users with tools for developing multitouch interaction is a promising step toward the materialization of ubiquitous computing. This survey frames the state of the art of existing multitouch software development tools from an end-user programming perspective.This research has been partially funded by the EUFP7 project meSch (grant agreement 600851 and CREAx grant (Spanish Ministry of Economy and Competitivity TIN2014-56534-R

Designing Mobile Applications for Emergency Response: Citizens Acting as Human Sensors

When an emergency occurs, citizens can be a helpful support for the operation centers involved in the response activities. As witnesses to a crisis, they initially can share updated and detailed information about what is going on. Moreover, thanks to the current technological evolution people are able to quickly and easily gather rich information and transmit it through different communication channels. Indeed, modern mobile devices embed several sensors such as GPS receivers, Wi-Fi, accelerometers or cameras that can transform users into well-equipped human sensors. For these reasons, emergency organizations and small and medium enterprises have demonstrated a growing interest in developing smart applications for reporting any exceptional circumstances. In this paper, we present a practical study about this kind of applications for identifying both limitations and common features.This work is supported by the project emerCien grant funded by the Spanish Ministry of Economy and Competitivity (TIN2012-09687)

Galaxy Formation in Heavily Overdense Regions at \u3cem\u3ez\u3c/em\u3e ~ 10: The Prevalence of Disks in Massive Halos

Using a high-resolution cosmological numerical simulation, we have analyzed the evolution of galaxies at z ~ 10 in a highly overdense region of the universe. These objects could represent the high-redshift galaxies recently observed by the Hubble\u27s Wide Field Camera 3 and could as well be possible precursors of QSOs at z ~ 6-7. To overcome the sampling and resolution problems in cosmological simulations of these rare regions, we have used the constrained realizations method. Our main result for z ~ 10 shows the high-resolution central region of 3.5 h–1 Mpc radius in comoving coordinates being completely dominated by disk galaxies in the total mass range of ≳ 109 h–1 M☉. We have verified that the gaseous and stellar disks we identify are robust morphological features, capable of surviving the ongoing merger process at these redshifts. Below this mass range, we find a sharp decline in the disk fraction to negligible numbers. At this redshift, the disks appear to be gas-rich compared to z = 0, and the dark matter halos baryon-rich, by a factor of ~2-3 above the average fraction of baryons in the universe. The dominance of disk galaxies in the high-density peaks during the epoch of re-ionization is contrary to the morphology-density trend observed at low redshifts