Clusters Case Study

As this matter spirals into the black hole it creates what is known as an accretion disk, which accelerates and heats up emitting X-rays which can then be detected by astronomers.[6]

The super strong gravity of a black hole pulls gases off nearby stars with such a force that the gases give off x-rays as they form an accretion disk of matter that spirals into the black hole. (Gallant R ., 2000).

The MACHO Project is a collaboration between scientists at the Mt. Stromlo & Siding Spring Observatories, the Center for Particle Astrophysics at the Santa Barbara, San Diego, & Berkeley campuses of the University of California, and the Lawrence Livermore National Laboratory. Their primary aim is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose they must have built a two-channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is

Complete the table based on the readings for this week: Ch. 1–4 of The Essential Cosmic Perspective.

In this paper I will explain how astronomers determine the composition, temperature, speed, and rotation rate of distant objects using various methods. I will explain the properties of stars. I will also summarize the complete lifecycle of the Sun and determine where the Sun is currently in its lifecycle.

UNSWA  -­  University  of  New  South  Wales SCI  -­  Faculty  of  Science PHYS  -­  School  of  Physics Module  3  (Weeks  5-­6)  —  Life  on  Earth  and  in  the  Solar  System PHYS1160-­5144_01311

The amazing amount of radiation coming from the disk of gas is ripping the galaxy apart.

This led to two disk-dominated galaxies were forced by gravity to merge into a single galaxy. The merger had also destroyed the disks and produced a huge pileup of stars.

bands as all the stars of its (∼ 1011 L ) host galaxy, while a typical QSO is by a factor of

During the 1970s, dark matter had been discovered accidentally by astronomers Vera Rubin and Kent Ford, they were observing galaxies and they noticed that stars far from the galaxy centre had a velocity similar to the celestial objects closer in. The observation was unexpected due to the visible mass of galaxies lacking the required gravity to keep the further stars in the orbit, therefore the astronomers were faced with a “missing mass” problem and the concept of dark matter had been created (16). The main problem with dark matter is that we can’t observe it directly, we must indirectly study its interaction with normal matter to be learn more about it (17). There may be a misconception between what is observed and what is known to be there, for example; if a man is floating mid-air, due to the fact that humans are unable to fly; it can be concluded that there must be something holding the man up there (2). In 1997, Hubble Space Telescope revealed light from far galaxies bent due a mass of 250 times greater than the visible mass which that scientists believe dark matter is the reason for (18). Also, NASA’s Chandra X-ray observatory had been used by astronomers to measure the allocation of dark matter in an immense constellation of galaxies located around a billion light year from earth, the cluster is engulfed by a significant amount of clouds of hot gas, from the observation it had been found that the amount of dark matter is a hundred trillion more than the mass of the sun which held the cluster of gravities together (17). Comprehending dark matter is an important task to understand the most vital aspects of the

“Active galactic nuclei” are objects occupying the center of many galaxies that consist of an accreting supermassive black hole and are some of the most luminous and powerful bodies in our known Universe. In the galactic-BH accretion process, gaseous matter from the galaxy is pulled into the black hole and is converted to into radiation that is then released radially outward into the host galaxy. Due to the rapid-fire accretion onto the Supermassive Black Hole, Active Galactic Nuclei (AGN) can emit radiation into their host galaxies that span much of the electromagnetic spectrum from X-rays, IR, UV, and radio waves. Researchers have organized AGN into groups based on their

Quasars are in the centres of galaxies. Such galactic centres are called active galactic nuclei. The bolt of their energy, spewing forth in the form of a powerful radiation jet, the length of which, puts even our entire solar system to shame! Specifically, if a large portion of this ejected energy heads towards earth, it is known as a quasar. But if earth is in the active galactic nucleus’ sight, it has an even more spine-chilling name, a blazar.

By conducting an extensive follow-up survey of an all-sky X-ray point source catalog to look for galaxy overdensities, we will obtain a sample of such galaxy clusters. The primary question the sample will answer is whether there are other extreme-BCG clusters, similar to the Phoenix cluster, in our universe. This will tell us about the nature of highly efficient star formation in a galaxy cluster by distinguishing a short-lived phenomenon from a common occurrence in cool

In these stellar nurseries, dense parts of these clouds undergo gravitational collapse and compress to form a rotating gas globule.

Solar modulation of galactic cosmic rays (GCR) has been a subject of intense research, especially to assess the continuously changing behaviour of the sun and its influence on cosmic rays. This modulation of GCR intensity associated with ~11-year solar activity cycle has been studied from past several decades (e.g., Forbush, 1954; Burlaga et al., 1985; Venkatesan and Badruddin, 1990; Storini et al., 1995; Sabbah and Rybansky, 2006; Kudela, 2009; Ahluwalia et al., 2010; Heber, 2013; Chowdhury, Kudela, and Dwivedi, 2013; and references therein). The long-term GCR modulation shows ~22-year cycle related to the solar magnetic cycle as the solar polarity reverses near solar maximum of very activity cycle; the polarity dependant effects on cosmic rays have also been an area of active research (e.g., Jokipii, Levy, and Hubbard, 1977; Potgieter and Moraal, 1985; Smith and Thomas, 1986; Cliver and Ling, 2001; Kota 2013; Potgieter, 2014; Laurenza et al., 2014; Potgieter et al., 2014; Thomas, Owens, and Lockwood, 2014; Thomas et al., 2014; and references therein).