What does "QGs" mean?
Table of Contents
QGs stands for quiescent galaxies. These are galaxies that have stopped forming new stars and are mostly made up of older stars. They appear more red in color because they lack younger, blue stars.
Size and Growth
Recent studies show that QGs can grow in size over time. For example, larger QGs have shown an increase in size of up to 110% in certain types of light. This growth is partly due to the addition of newly formed galaxies that have stopped creating stars, called newcomers.
Characteristics
QGs tend to be more massive and smaller than their star-forming counterparts. They also have a denser concentration of stars within their centers. The more massive a QG is, the redder and smaller it usually becomes.
Importance of Bulges
The increase in size of QGs is mainly due to the development of bulges, which are the dense central parts of galaxies. This suggests that the way QGs are growing is linked to changes happening within them rather than just the addition of new galaxies.
Observations Over Time
As time goes on, more galaxies transition from being star-forming to quiescent. This shift affects how we understand galaxy evolution and the mechanisms behind their growth and size changes.