Introduction
Black HolesDue to the lack of understanding surrounding the evolution and nature of active galactic nuclei and the fact that this area has not been researched in depth, the objective now is to identify possible correlations using raw images and the information within them provided by the Hubble Space Telescope. Through the utilization of a computer software called DS9, it is possible to analyze raw images of 16 quasars--quasi-stellar radio sources, which are a type of active galactic nuclei--along with their neighboring objects taken by the Hubble to collect quantitative and qualitative data. Since not much research effort has been allocated into AGN phenomena, it is plausible that a relationship will be established between the number, type, and distance of objects surrounding a known quasar and the nature of said quasar. For example, a large galaxy that is a short distance from the quasar may cause the subject galaxy to display a greater luminosity and energy output than typical galaxies do. The gathering of evidence coupled with correct reasoning has the potential to lead astronomers to the resolution of this strange phenomenon and to unlocking the secrets to the life cycle and evolution of galaxies.
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Galaxy TypesThe main types of galaxies are spirals, irregulars, and ellipticals. Spiral galaxies contain a central galactic bulge which consists of older stars and a disk with arms of gas, dust, and younger stars. It also features a halo around the galaxy, which comprises mainly of older stars, much like the bulge does. The galaxy which contains Earth’s solar system, the Milky Way, is a spiral galaxy. Irregular galaxies feature distinct shapes depending on the galaxy. They are classified as such due to the lack of a consistent shape and symmetry. Elliptical galaxies take on a stretched sphere-like formation and consist of mainly stars which have been burning for a long time. It is often thought that colliding galaxies may form these ellipticals and that no new star formation occurs in them. Some astronomers speculate that elliptical galaxies are at the final stage of galactic evolution and will eventually die out. Aside from the three major classifications, there are also lenticular galaxies. In short, lenticular galaxies are a subclassification of spiral galaxies that do not have arms, yet still share many similarities with spirals.
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Galaxy DisturbancesIn addition to galaxy types, there are also four main types of disturbances relevant to this study. The ongoing merger is a type of disturbance where two or more galaxies and their nuclei are interacting to coalesce into a larger galaxy. In these galaxy systems, the nuclei may pass each other several times before their supermassive blackholes merge and the irregular shapes of gas and dust start to become uniform again. Their components--stars, planets, dust, gas, etc-- are stretched into strands which bridge the two nuclei. Finally, the nuclei begin to combine and the new galaxy is formed as all the matter is regrouped. The second disturbance is the recent merger; these are objects that seem to have a strange shape and trails of gas and dust because they are in the process of reshaping, which immediately follows the merging of the nuclei. Undisturbed objects are isolated and unaffected by any other bodies. The unresolved category of disturbances was included to classify objects whose disturbances were not exactly clear or recognizable; in terms of relevance, it did not provide much information about the correlation between these objects and the 16 central quasars.
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There are also two main classifications of active galactic nuclei: seyfert galaxies and quasars. Seyfert galaxies emit sums of energy equivalent to that of all of the stars in the entire galaxy in the nucleus alone, whereas a quasar produces enough light to be brighter than the stars by a factor of 100 or greater. Luminous quasars rarely exist in the universe and are only likely to be found shining from long distances. At such distances, the bright nucleus outshines the host galaxy and its stars; for this, a star-like object is observed rather than a galaxy, and these objects are noted as quasi-stellar (Peterson, 1997, 1). Quasars are the main focus of this study.