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Near-field cosmology -- using detailed observations of the Local Group and its environs to study wide-ranging questions in galaxy formation and dark matter physics -- has become a mature and rich field over the past decade. There are lingering concerns, however, that the relatively small size of the present-day Local Group ($sim 2$ Mpc diameter) imposes insurmountable sample-variance uncertainties, limiting its broader utility. We consider the region spanned by the Local Groups progenitors at earlier times and show that it reaches $3 approx 7$ co-moving Mpc in linear size (a volume of $approx 350,{rm Mpc}^3$) at $z=7$. This size at early cosmic epochs is large enough to be representative in terms of the matter density and counts of dark matter halos with $M_{rm vir}(z=7) lesssim 2times 10^{9},M_{odot}$. The Local Groups stellar fossil record traces the cosmic evolution of galaxies with $10^{3} lesssim M_{star}(z=0) / M_{odot} lesssim 10^{9}$ (reaching $M_{1500} > -9$ at $zsim7$) over a region that is comparable to or larger than the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It is highly complementary to the HUDF, as it probes much fainter galaxies but does not contain the intrinsically rarer, brighter sources that are detectable in the HUDF. Archaeological studies in the Local Group also provide the ability to trace the evolution of individual galaxies across time as opposed to evaluating statistical connections between temporally distinct populations. In the JWST era, resolved stellar populations will probe regions larger than the HUDF and any deep JWST fields, further enhancing the value of near-field cosmology.
We use recent proper motion measurements of the tangential velocity of M31, along with its radial velocity and distance, to derive the likelihood of the sum of halo masses of the Milky Way and M31. This is done using a sample halo pairs in the Bolsho
We explore the characteristics of the cosmic web around Local Group(LG) like pairs using a cosmological simulation in the $Lambda$CDM cosmology. We use the Hessian of the gravitational potential to classify regions on scales of $sim 2$ Mpc as a peak,
We present the first detailed structure formation and radiative transfer simulations of the reionization history of our cosmic neighbourhood. To this end, we follow the formation of the Local Group of galaxies and nearby clusters by means of constrai
The confinement of most satellite galaxies in the Local Group to thin planes presents a challenge to the theory of hierarchical galaxy clustering. The PAndAS collaboration has identified a particularly thin configuration with kinematic coherence amon
We contend that a single power law halo mass distribution is appropriate for direct matching to the stellar masses of observed Local Group dwarf galaxies, allowing the determination of the slope of the stellar mass-halo mass relation for low mass gal