The central question of this Letter is how and when the Milky Way assembled its stellar mass. This issue is addressed by tracing the formation history of spiral galaxies which closely resemble the Milky Way.
TITLE: Comparing the Ancient Star Formation Histories of the Magellanic Clouds AUTHORS: Daniel R. Weisz, Andrew E. Dolphin, Evan D. Skillman, Jon Holtzman, Julianne J. Dalcanton, Andrew A. Cole, Kyle Neary AUTHORS’ INSTITUTION: University of Washington The evolution of galaxies can be investigated in two ways: we can observe galaxies at farther distances to get a picture of [...]
The authors have identified several satellite galaxies confined to a plane in their orbits around our nearest neighbor, the Andromeda Galaxy. Such a planar structure is perhaps at odds with our current understanding of galaxy formation.
Pairs of dwarf galaxies in the Local Group are much more common than what expected from N-body/semi-analytic models of galaxy formation.
Astronomers in Leiden have measured star formation rates across a large range in redshift with H-alpha spectroscopy for the first time, which is a huge leap forward in our ability to compare the local Universe with high-redshift.
In this paper, the authors describe a new galaxy simulation that includes molecular hydrogen, the site of star formation, and discuss what happens with and without it.
Researchers at Caltech have used data from the Keck Baryonic Structure Survey to place quantitative constraints on the circumgalactic medium around galaxies at z~2. Measurements like these help us fine-tune our understanding of the interplay between gas and galaxies and, ultimately, galaxy formation and evolution.
When the light from a distant quasar finally arrives at Earth, it often carries far more information than it did when it was emitted – the shadows of gas and galaxies that have intervened over the cosmic distances between us and the source. These features can tell us how the universe evolves in both space and time, by allowing us to sample both low and high redshifts for structures that would not otherwise be visible. This paper uses a new IR spectrograph, FIRE, deployed on the Magellan 6.5 m telescopes, to present the first high-redshift sample of Mg II absorption systems, including the most distant Mg II system yet found (z = 5.33). The authors show that the number of strong Mg II systems appears to peak and decline in number along with the star formation history of the universe, suggesting a correlation between the two, while weak Mg II systems stay mysteriously constant.
A new dwarf galaxy has been detected a record-breaking 10 billion light years from Earth, using a method based on gravitational lensing. The satellite galaxy is composed mainly of dark matter and is too faint to be observed directly with the current generation of optical telescopes.