There is a common misconception that astronomers used to think that elliptical galaxies were the evolutionary forerunners to spiral galaxies, because Hubble himself referred to elliptical galaxies as ‘early-type’ and spiral galaxies as ‘late-type’. Almost 60 of the galaxies that are currently known are spirals. Elliptical galaxies are typically found in galaxy clusters. The shape of the arms varies a lot, but in general a condensed center is clearly distinguished surrounded by a disk from which the spirals sprout. The field shown measures 6.8 x 6.8 arcmin. A spiral galaxy It is a monumental cluster of stars in the shape of a disk with spiral arms, reminiscent of the shape of a pinwheel. Reconnection effects could convert some of the energy of the. The image is a composite of three images taken behind three different filters: U (360 nm 10 min), B (420 nm 6 min) and R (600 nm 2:30 min) during a period of 0.7 arcsec seeing. This emission has a form of magnetic arms that resembles the spiral structure of the galaxy. Sa galaxies have very tightly wound arms around. Spiral galaxys are divided into three main types depending on how tightly wound their spiral arms are: Sa, Sb and Sc. In a spiral galaxy, the stars, gas and dust are gathered in spiral arms that spread outward from the galaxys center. At the indicated distance, the edge of the field shown corresponds to about 200,000 light-years, or about twice the size of the Milky Way galaxy. Spiral galaxies get their name from the shape of their disks. The distance is about 60 million light-years, but the excellent optical quality of the VLT and FORS allows us to see an incredible wealth of details. The disk is a region of star formation and has a great deal of gas and dust. NGC 1232 is located 20º south of the celestial equator, in the constellation Eridanus (The River). The disk of the galaxy contains the spiral arms. Note the distorted companion galaxy on the left side, shaped like the greek letter "theta". The colours of the different regions are well visible : the central areas contain older stars of reddish colour, while the spiral arms are populated by young, blue stars and many star-forming regions. It is based on three exposures in ultra-violet, blue and red light, respectively. On your lab sheet list two characteristics of a spiral galaxy, an elliptical galaxy and an irregular galaxy. These galaxies are still forming or are the leftovers of two or more clashing galaxies. This spectacular image of the large spiral galaxy NGC 1232 was obtained on September 21, 1998, during a period of good observing conditions. An irregular galaxy doesn’t have a defined shape or pattern.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |