Wednesday, October 03, 2007
A census of nearby galaxies
In Mining the Local Volume 550 galaxies have been found within 10 million parsecs. A surprising observation was that there seems to be an absence of dark matter outside of the galaxy groups - if I understood the paper correctly. The preprint had some nice graphics too!
Surprisingly Evolved Galaxies in the Early Universe
This astrophysics preprint describes A Population of Massive and Evolved Galaxies at z>=5, when the universe was less than a billion years old, which "... seems surpising at first sight". z is the redshift which according to the standard Big Bang models of cosmology is related to the age of the galaxy.
Here's another preprint Morphologies of Two Massive Old Galaxies at z ~ 2.5 which says
The galaxies found in this study are remarkable in that they contain a large stellar mass, have small physical sizes and that their main epoch of star formation occured at z >= 10. Galaxies with similar properties have, however, also been found by others.
Here's another preprint Morphologies of Two Massive Old Galaxies at z ~ 2.5 which says
Considerable observational evidence has built up over
the past few years that a substantial fraction of the mas-
sive galaxies around us today were already massive at
very early epochs.
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