Using 22 hydrodynamical simulated galaxies in a LCDM cosmological context werecover not only the observed baryonic Tully-Fisher relation, but also theobserved "mass discrepancy--acceleration" relation, which reflects thedistribution of the main components of the galaxies throughout their disks.This implies that the simulations, which span the range 52 < V$_{\rm flat}$ <222 km/s where V$_{\rm flat}$ is the circular velocity at the flat part of therotation curve, and match galaxy scaling relations, are able to recover theobserved relations between the distributions of stars, gas and dark matter overthe radial range for which we have observational rotation curve data.Furthermore, we explicitly match the observed baryonic to halo mass relationfor the first time with simulated galaxies. We discuss our results in thecontext of the baryon cycle that is inherent in these simulations, and withregards to the effect of baryonic processes on the distribution of dark matter.

The detection of optical surface brightness structures in the sky withmagnitudes fainter than 30 mag/arcsec^2 (3sigma in 10x10 arcsec boxes; r-band)has remained elusive in current photometric deep surveys. Here we show howpresent-day 10 meter class telescopes can provide broadband imaging 1.5-2 magdeeper than most previous results within a reasonable amount of time (i.e. <10hon source integration). In particular, we illustrate the ability of the 10.4 mGran Telescopio de Canarias (GTC) telescope to produce imaging with a limitingsurface brightness of 31.5 mag/arcsec^2 (3sigma in 10x10 arcsec boxes; r-band)using 8.1 hours on source. We apply this power to explore the stellar halo ofthe galaxy UGC00180, a galaxy analogous to M31 located at ~150 Mpc, byobtaining a surface brightness radial profile down to mu_r~33 mag/arcsec^2.This depth is similar to that obtained using star counts techniques of LocalGroup galaxies, but is achieved at a distance where this technique isunfeasible. We find that the mass of the stellar halo of this galaxy is ~4x10^9Msun, i.e. 3+-1% of the total stellar mass of the whole system. This amount ofmass in the stellar halo is in agreement with current theoretical expectationsfor galaxies of this kind.

We study the physical properties of a spectroscopic sample of 28 star-forminggalaxies in a large filamentary structure in the COSMOS field at $z\sim$0.53,with spectroscopic data taken with the Keck/DEIMOS spectrograph, and comparethem with a control sample of 30 field galaxies. We spectroscopically confirmthe presence of a large galaxy filament ($\sim$ 8 Mpc), along which fiveconfirmed X-ray groups exist. We show that within the uncertainties, theionization parameter, equivalent width (EW), EW versus specific star-formationrate (sSFR) relation, EW versus stellar mass relation, line-of-sight velocitydispersion, dynamical mass, and stellar-to-dynamical mass ratio are similar forfilament and field star-forming galaxies. However, we show that on average,filament star-forming galaxies are more metal-enriched ($\sim$ 0.1$-$0.15 dex),possibly due to the inflow of the already enriched intrafilamentary gas intofilament galaxies. Moreover, we show that electron densities are significantlylower (a factor of $\sim$17) in filament star-forming systems compared to thosein the field, possibly because of a longer star-formation timescale forfilament star-forming galaxies. Our results highlight the potentialpre-processing role of galaxy filaments and intermediate-density environmentson the evolution of galaxies, which has been highly underestimated.