The cosmic web of the Local Universe: cosmic variance, matter content and its relation to galaxy morphology

We present, for the first time, a Local Universe (LU) characterization using high-precision constrained N-body simulations based on self-consistent phase-space reconstructions of the large-scale structure in the Two-Micron All-Sky Galaxy Redshift Survey. We analyse whether we live in a special cosmic web environment by estimating cosmic variance from a set of unconstrained Lambda CDM simulations as a function of distance to random observers. By computing volume and mass filling fractions for voids, sheets, filaments and knots, we find that the LU displays a typical scatter of about 1 sigma at scales r greater than or similar to 15 h(-1) Mpc, in agreement with Lambda CDM, converging to a fair unbiased sample when considering spheres of about 60 h(-1) Mpc radius. Additionally, we compute the matter density profile of the LU and we have found a reasonable agreement with the estimates of Karachentsev only when considering the contribution of dark haloes. This indicates that observational estimates might be biased towards low-density values. As a first application of our reconstruction, we investigate the likelihood that different galaxy morphological types inhabit certain cosmic web environments. In particular, we find that, irrespective of the method used to define the web, either based on the density or the peculiar velocity field, elliptical galaxies show a clear tendency to preferentially reside in clusters as opposed to voids (up to levels of 5.3 sigma and 9.8 sigma, respectively) and conversely for spiral galaxies (up to levels of 5.6 sigma and 5.4 sigma, respectively). These findings are compatible with previous works, albeit at higher confidence levels.