Galaxy enlargement is generally accepted to be through merger, called the Standard Model, where galaxies coalesce by gravitational attraction. This fails to explain the association between Galaxies and the Super Massive Black Hole (SMBH) lurking in the centre.
SMBH/Galaxy association.
1 There's a correlation in size as the SMBH is about 0.5% the mass of the Galaxy suggesting they increase or evolve together.
2 There only appear to be one and right in the centre.
3 The plane on which the galaxy forms respects the SMBH - if it jets (presumably from the poles) that is at 90° to the galactic plane as a recognition of its 'equator'.
4 The entire galaxy rotates or orbits about this SMBH like a vast disc.
5 This object is unusually large, at least 1000 times bigger than anything else, suggesting a special evolutionary path.
Sgr A* - Galactic centre in the x-ray.
SMBH Galaxy Core
Some estimation of the properties of such a massive object in such a matter rich environment can be guest. There are Black Holes (BH) of this size or bigger elsewhere that are the brightest objects in the Universe called quasars. That description will not fit Sgr A* galaxy core which should be bright in the x-ray, flare as stars are attracted and include a large accretion disc all of which it does not have. It appears discreet, dull and mysterious. Quasars and SMBH are not at all comparable.
The rotation speed has been unusually difficult to calculate suggesting strange characteristics.
We can be confident its a BH as there is no other object it could be - which is not totally true. Part of the prediction concerning BH (in Relativity) is also describes a second and associated object of unknown properties. Matter falling into the BH in the accretion process does not all land on the compact surface and this second object is where it may emerge called a white hole (WH).
This may inhabit the Galaxy centre and not a SMBH. We may be the recipient of matter from a BH elsewhere in the Universe. Attempting to prove the properties of what may be a massive white hole are unnecessary. Looking at the causal link and association described above between Galaxy features and the central object may determine its properties. Contrasting galaxy features to a merger process in the Standard Model with a SMBH and comparing this to a more relative process with a Super Massive White Hole (SMWH) in the Galaxy middle will show which is more credible.
Merger of Galaxies v Relative Growth.
The Relative Model suggests expansion where matter in the Galaxy spirals away from the centre and is constantly replaced. As the galaxy grows so does the SMWH forming a correlation in size as the central object takes 0.5% of the passing matter (and not through regular accretion so no large disc and not bright in the x-ray). It also suggests that only one SMWH is needed, you won’t find two or more, and always in the Galactic centre like an axis around which all matter will rotate. Mass expanding from the middle will give galaxies a circular and symmetrical character with the SMWH right in the heart.
The Standard Model predicts a more chaotic galaxy. Even a ‘sympathetic’ merger where two galaxies come harmoniously together will overlay features like spiral arms and bulges to form concentrations of stars, odd shapes and deformity.
Circular and symmetrical galaxy.
Matter expanding from the SMWH in the Relative Model will respect the magnetic field of the central object initially and simply continues that motion forming a vast disc. It would be unlikely that even a super massive central object could dominate matter over the full width of a galaxy.
New stars forming around the SMWH will give them an even and near circular orbit. The amount of very irregular or elliptical orbits will be low (maybe less than 1%) and incoming stars from merger will create a high percentage of elliptical orbits (40-50% would not be unexpected). The actual amount of elliptical orbits is very low which is not associated to the Standard Model.
The Relative Model suggest that the bulge is a huge star-forming zone with matter pouring from the SMWH forming stars that spiral across the galaxy over time. This makes it full of young stars whereas the Standard Model suggests it is full of old, however, when the ages of stars are analysed they appear to be largely young. This is called the ‘paradox of youth’ and is not related to the Standard Model.
If the Relative Model is true and the bulge is a huge star-forming region with stars spiralling away over time then they will be generally aged, right across the Galaxy, according to distance from the centre. This suggests younger stars are found at the bulge and the older at the edge of the glowing galaxy which is in general what has been established. (M. Arnaud. ‘The Evolution of Galaxy Clusters Across Cosmic Time’ 2010)
Unlike much discussed here where the Standard Model may, at a pinch, be viable it is impossible for the random, chaotic, and disruptive merger processes to form a grading of stars in age according to distance from the bulge.
What the glowing galaxy represents is the evolution of stars. They predominantly form in the bulge (barring some notable exceptions like special star-forming zones called nebular etc and the possible condensing of stars from clouds of matter in the general interstellar medium) and spiral away over time to eventually die. Stars have a lifetime and this is represented by the bright galaxy. Though they must eventually go dark it is not the end of the matter they are made from. That will continue to spiral away forming the Dark Halo as a star grave yard. So the whole galaxy is the sum of mass passed through the bridge over its lifetime.
Dark Halo around galaxy, in red, showing graveyard of stars.
Galaxy size.
The Relative Model suggests a steady outward flow of matter creating a growth process so galaxies of a similar age may have a similar mass. Plotted on a graph their sizes will fall into a growth curve. This is called Freeman’s Law. In the Standard Model galaxies start small and randomly merge which will not result in galaxies of similar large size.
The Sun.
The sun is not orbiting in an exact circle around the galaxy. We are gradually moving away as a likely illustration of outward drift. The Sun may have formed in the bulge with most of the stars around us from matter passed through space time and we have gradually spiralled away over the Sun’s lifetime.
Spiral Arms.
These features are not random. They are connected to a bar of stars that crosses the centre of the bulge right through the SMWH. Matter as two streams like huge jets steadily move away through outward drift and are replaced from the centre as part of the Relative Model. As they pass out of the direct magnetic field of the SMWH they form two spirals as part of outward drift and rotation. These spiral arms are the bar of yesteryear.
Bar of stars represents outward drift that become spiral arms.
The interaction between these two jets of matter and a SMWH or a bar of stars and a SMBH in the Standard Model (there must be some as they occupy the same space) are not an interaction recognized about BHs.
Bar formed by two massive jets from equator of SMWH (not BH)
None of the galaxy features described here can be associated with merger - all can be linked to growth. Some of the reasoning’s in merger are difficult to believe but a few, the ageing of stars from the bulge and the formation of the bar, are impossible.
