Galaxies can have different morphologies including elliptical, spiral, and irregular shapes. Elliptical galaxies have a spherical bulge of stars with no discernible disk structure, while spiral galaxies contain a central bulge and disks with spiral arms containing younger stars. Spiral galaxies are further classified based on characteristics of their bulge and spiral arm structure. The Hubble sequence arranges galaxies from elliptical to spiral shapes based on their morphology, with elliptical galaxies generally containing older stellar populations. Interactions between galaxies can transform their shapes over time.

1. Sdss
Ned
Simbad
GALAXY MORPHOLOGY
Characteristics of galaxies
-*a ball or a frisbie configuration
-ball aka bulge(circle or the center circle of the galaxies)swarm of stars (mob of bee
hives) characterized by chaotic orbits and
3D configurationball **bulge ones have older stars
-*bar..
There is generally a bar and bulge in the lower section of the hubble chart
-*disk-coherent/ordered motion in a plane and is a flat configuration
-Disk could be smooth/spiral arms/ “irregular patchy” Disks have more young
stars
-S0 and Sa are distinguished from the rest when seen from a disk view because of the big
bulge they have.
-When going from left to right in the hubble chart, the bulge goes down. The brightest
stars in a (disk) galaxy show the spiral arms (spiral galaxies)
-Eliptical Galaxies and spiral galaxies
-put in presentation-hubble tuning fork diagram. Named after Edwin Hubble. Aka hubble
morphological sequence (sequence of different types of forms) *look up*
-Eliptical-(bulge only)( look smoother)
**Irregular is disk only
BARRED GALAXY
-Have a linear structure in the feature.
-have younger stars but don’t have anything to organize them into a nice patterns
ELIPTICAL GALAXIES AND THEIR NUMBER FIGURES
-(equation on the page)
-depends on the shape (oval or circle)
SPIRAL-
-capital B makes the difference in the description of the bulge and the arms span. Little B
has bigger bulge bigger B has closer arms (I think)(look “patchier”)
THE EARLIER IN THE ALPHABET IN THE HUBBLE CHART, THE OLDER IT IS

2. -When forming a disk of stars, some stars gather in a linear structure
** transformations from left to right does not really happen but two spirals can mix and turn into
something unidentified but later become an elliptical
-Eliptical galaxies spin with no net rotation
-spirals have the differential rotation because of the different distance of the center
-younger stars form along the spiral arms.
-Regions in crowded galaxy neighborhoods, there are more elliptical galaxies…far away ones
are spiral
-the more gas and dust, the harder it is to see smoothly (spiral)
-Elipticals could be a result of a spiral collision.
http://www.absoluteastronomy.com/topics/Barred_spiral_galaxy