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We use a 380 h-1 pc resolution hydrodynamic AMR simulation of a cosmic filament to investigate the orientations of a sample of ~100 well-resolved galactic disks spanning two orders of magnitude in both stellar and halo mass. We find: (i) At z=0, there is an almost perfect alignment at a median angle of 18 deg, in the inner dark matter halo regions where the disks reside, between the spin vector of the gaseous and stellar galactic disks and that of their inner host haloes. The alignment between galaxy spin and spin of the entire host halo is however significantly weaker, ranging from a median of ~46 deg at z=1 to ~50 deg at z=0. (ii) The most massive galaxy disks have spins preferentially aligned so as to point along their host filaments. (iii) The spin of disks in lower-mass haloes shows, at redshifts above z~0.5 and in regions of low environmental density, a clear signature of alignment with the intermediate principal axis of the large-scale tidal field. This behavior is consistent with predictions of linear tidal torque theory. This alignment decreases with increasing environmental density, and vanishes in the highest density regions. Non-linear effects in the high density environments are plausibly responsible for establishing this density-alignment correlation. We expect that our numerical results provide important insights for both understanding intrinsic alignment in weak lensing from the astrophysical perspective and formation and evolution processes of galactic disks in a cosmological context.
We have searched for presence of current star formation in outer stellar rings of early-type disk (S0-Sb) galaxies by inspecting a representative sample of nearby galaxies with rings from the recent Spitzer catalog ARRAKIS (Comeron et al. 2014). We h
Disk scale length and central surface brightness for a sample of about 29955 bright disk galaxies from the Sloan Digital Sky Survey have been analysed. Cross correlation of the SDSS sample with the LEDA catalogue allowed us to investigate the variati
We investigate the correlations between optical and radio isophotal position angles for 14302 SDSS galaxies with $r$ magnitudes brighter than 18 and which have been associated with extended FIRST radio sources. We identify two separate populations of
We present a measurement of the correlation function between luminous red galaxies and cool gas traced by Mg II lambda lambda 2796, 2803 absorption, on scales ranging from about 30 kpc to 20 Mpc. The measurement is based on cross-correlating the posi
We aim to identify and quantify the effects of the satellite distribution around a sample of galaxies in the Catalogue of Isolated Galaxies (CIG), as well as the effects of the Large Scale Structure (LSS) using the SDSS-DR9. To recover the physically