Faint blue galaxy
Encyclopedia
The faint blue galaxy problem in astrophysics
first arose with observations starting in 1978 that there were more galaxies with a bolometric magnitude > 22 than then-current theory predicted. Galaxies can appear faint because they are small or because they are far away. Neither explanation, nor any combination, initially matched the observations. The distribution of these galaxies has since been found to be consistent with Cosmic Inflation
, measurements of the Cosmic Microwave Background, and a nonzero cosmological constant, that is, with the existence of the now-accepted dark energy
. It thus serves as a confirmation of supernova
observations requiring dark energy.
A second problem arose in 1988, with even deeper observations showing a much greater excess of faint galaxies. These are now interpreted as dwarf galaxies experiencing large bursts of stellar formation, resulting in blue light from young, massive stars. Thus F.B.G.s are extremely bright for their size and distance.
Most F.B.G.s appear between red-shift 0.5 and 2. It is believed that they disappear as separate objects by merger with other galaxies. How ever, the problem has not been definitively solved.
Astrophysics
Astrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
first arose with observations starting in 1978 that there were more galaxies with a bolometric magnitude > 22 than then-current theory predicted. Galaxies can appear faint because they are small or because they are far away. Neither explanation, nor any combination, initially matched the observations. The distribution of these galaxies has since been found to be consistent with Cosmic Inflation
Cosmic inflation
In physical cosmology, cosmic inflation, cosmological inflation or just inflation is the theorized extremely rapid exponential expansion of the early universe by a factor of at least 1078 in volume, driven by a negative-pressure vacuum energy density. The inflationary epoch comprises the first part...
, measurements of the Cosmic Microwave Background, and a nonzero cosmological constant, that is, with the existence of the now-accepted dark energy
Dark energy
In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted theory to explain recent observations that the universe appears to be expanding...
. It thus serves as a confirmation of supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
observations requiring dark energy.
A second problem arose in 1988, with even deeper observations showing a much greater excess of faint galaxies. These are now interpreted as dwarf galaxies experiencing large bursts of stellar formation, resulting in blue light from young, massive stars. Thus F.B.G.s are extremely bright for their size and distance.
Most F.B.G.s appear between red-shift 0.5 and 2. It is believed that they disappear as separate objects by merger with other galaxies. How ever, the problem has not been definitively solved.