Editors' ChoiceNear-Field Cosmology

Is the Local Group useful for cosmology?

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Science  12 Aug 2016:
Vol. 353, Issue 6300, pp. 661-662
DOI: 10.1126/science.353.6300.661-c

A nighttime view from Earth of our Milky Way Galaxy


Our Milky Way Galaxy is the second largest member of the Local Group, a gravitationally bound assemblage of several dozen galaxies. Researchers in near-field cosmology use detailed studies of the Local Group to understand how galaxies form and evolve over cosmic time but have never been sure how well the Local Group represents the wider universe. Boylan-Kolchin et al. used cosmological simulations to demonstrate that the Local Group occupies a sufficiently large volume at high redshift to make it a representative sample, at least for the dwarf galaxies. They show that Local Group studies can complement deep observations of high-redshift galaxies, which are sensitive to different mass ranges.

Mon. Not. R. Astron. Soc. 462, L51 (2016).

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