Nature versus nurture in the growth of galaxies
Galaxies have more than doubled in size since they first formed, but why?
What came before clusters? Protoclusters
A galaxy cluster in the act of forming reveals some interesting details about the lives of galaxies.
Finding Galaxies at the Edge of the Universe
How can we find the distant galaxies that were responsible for bringing us out of the cosmic dark ages?
Reconstructing the histories of our nearest galactic neighbors
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 WashingtonThe evolution of galaxies can be investigated in two ways: we can observe galaxies at farther distances to get a picture of how galaxies appeared at earlier times (since the light from these distance sources requires time to reach our telescopes), or we can study the remnants of past events in our nearby universe. This paper is an example of the latter approach. Using archival data from the Hubble Space Telescope, the authors try to piece together the detailed history of how the Large and Small Magellanic Clouds formed their stars.The Large Magellanic Cloud and Small Magellanic Cloud (LMC and SMC) are two of the closest neighbors to our home galaxy, the Milky Way. In fact, they’re so close that they’re classified as satellite galaxies, meaning they’re gravitationally bound to the Milky Way in the same way the Earth is gravitationally bound to the Sun. They’re also rather smaller, less-thoroughly formed, and irregularly shaped than our own galaxy, being examples of dwarf galaxies. If you want to study populations of stars and how they form, it’s hard to find better subjects than the Magellanic clouds; they’re close enough that we can make out the individual stars (especially with a telescope with Hubble’s resolution) and they’ve been extensively investigated over the years, giving us a solid understanding of their sizes and distances and other properties.The stars that make up the LMC and SMC were formed over a period of many...
Using a Lens to Look Back in Time
Using massive gravitational lenses can help us study the evolution of galaxies over unprecedented time scales.