Galaxies

A wide-ranging malaria program of imaging and spectroscopy of galaxies by Spitzer will conduct, from the closest to the Milky Way to those found in the limits of the observable universe.

Ultra luminous Infrared Galaxies (ULIRGs)

The satellite IRAS discovered a class of ultra luminous galaxies that radiate more than 90% of infrared light. Studies show that optical and infrared most of these objects are in systems of galaxies in collision or interaction. The study of the nature of ULIRGs and their relation to active galaxies (see next paragraph) is one of the most important problems in astrophysics.

Spitzer will study their properties and their evolution at cosmological distances very large and determine the relationship between these galaxies and AGN. Spectroscopic measurements will determine the physical conditions of the optically invisible regions within these galaxies, providing information on their energy source.

Galaxies Active / Active Galactic Nuclei

 An active galaxy is characterized by a radiation no thermal extremely intense, typically at radio wavelengths and X-ray signal that are very energetic processes taking place in the center of these galaxies. The source of these energies is suspected to be a giant black hole located in the nucleus of the galaxy. The quasars, the radio galaxies and Seyfert galaxies are all active galaxies. Many of these objects are full of dust, in which case it can emit large amounts of infrared light. Spitzer AGN observed over long distances in an effort to understand the relationship between different types of AGN, the evolution of observable properties with time and physical processes which result in energy production.

Starburst Galaxies

Starburst galaxies exhibit unusually high rates of large-scale star formation and its light is dominated by both optical and infrared emission from massive young stars. The phenomenon "starburst" can be located near the center of the galaxy or may appear in the galactic disk. Increasing the rate of star formation is believed to be the result of a collision of galaxies or a gravitational encounter on a system of interacting galaxies. Spitzer will take advantage of the fact that galaxies "starburst" emit huge amounts of infrared radiation to conduct a comprehensive study of its distribution and evolution over cosmological timescales.

 Normal Galaxies

Most star systems extragaláticos (outside our galaxy) are normal galaxies do not exhibit any unusual features of active galaxies. Astronomers classify these galaxies by morphology in spiral, elliptical, or irregular. The sensitivity and unprecedented spatial resolution of Spitzer at mid-and far-infrared will enable astronomers to carry out comprehensive studies on normal galaxies from those found near the Milky Way, to those found in the confines of the Universe young. Systematic measurements of dust, gas and stars in galaxies are located at a distance of up to ten billion light years; astronomers will provide information to interpret the Spitzer observations of galaxies much more distant (and therefore are smaller). Other programs are responsible for detecting the faint halos whose existence is inferred from dynamical studies of spiral galaxies and the construction of maps of the distribution of molecular hydrogen in the disks of galaxies and the study of how the formation and evolution of stars depends on the metallicity of the galaxy.

Clusters of Galaxies

Galaxies are usually found in large clusters are gravitationally bound many times larger than the star clusters. A rich cluster containing thousands of galaxies and gas burning hot intergalactic inhomogeneous and can be detected in X-rays Spitzer investigated the production of low-mass stars and brown dwarfs because of the cold gas flows are gravitationally attracted to the cluster center in a confirmation of General Relative Theory (English) Einstein, massive galaxy clusters act as gravitational Lansing , where the objects located directly behind the clusters are increased in size & ntildeo apparent mass of the cluster. Spitzer used these alignments chance to take pictures of distant galaxies that would otherwise be too weak to be observed.

Interstellar Medium in External Galaxies

Astronomers know that galaxies contain not only stars. The interstellar medium that lies between the stars is made up of dust and gas atoms and molecules. Is the interstellar medium that provides the seeds for the formation Estela. Spitzer not only conducts a comprehensive study of the interstellar medium in our Galaxy but also gain valuable information on other galaxies. The measures taken in the H II regions (ionized hydrogen) in nearby galaxies will provide important data on how star formation is related to the general properties of the galaxy.