Every time a new ‘‘messenger” (different photon wavelengths or a different particle) has added to the list of observables accessible to astrophysicists, the Universe has appeared under a new light: it has revealed surprising features and triggered new questions, ultimately changing our understanding of fundamental physics and cosmology.Examples include the new elementary particles discovered in cosmic rays in the ‘30s and ‘40s, flavor oscillations from the solar and atmospheric neutrinos, or the revolutions brought by radio or X-ray astronomy. The last decade, a new branch of astronomy was born: high energy and very high energy gamma-ray astronomy.
Especially, 2OO4 was a very importand year for the gamma-rays astronomy. Firstly it was the year that marked the 30th aniversary of the discovery of the compact radio source Sgr A* (Balick and Brown 1974) which is now strongly believed to be the revelation of a supermassive black hole of a mass of (3 imes 10^{6} M odot ) that seats in the rotanional center of the Galaxy, according to the measurments of star motions near the Galactic Center (GC). Moreover it was the year that the first detection of gamma-rays from a compact region of size (sim 10') around Sgr A* with the INTEGRAL ( extit{International Gamma-Ray Astrophysics Laboratory } ) observatory in the energy rage from 20 to 100 keV (Belanger et al 2004) and with the HESS (High Energy Stereoscopic System) Cerenkov telescope array between 165 and 10 TeV (Aharonian et al 2004) took place. The detection of a high energy radiation source that appears to be pointlike and coincident with the Galactic Nucleus seems to be the reword of 30 years of observations. The GC is now observed also by the Fermi space observatory. When J.Co...
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...i.e. within (sim 100 ) Schwarzchild radii of the black hole). This fact must be explained by any model for the TeV gamma-rays and it seems to support the scenario where the gamma-rays are assosiated with electrons accelarated by the pulsar wind nebula.
However, protons may be accelarated close to the black hole, but be converted to gamma-rays only after travelling a significant distance away from the accelaration region (e.g. Atoyan n Dermer 2004; Aharonian n Neronov 2005; Ballantyne et al. 2007a). In the scenario presented by Ballantyne et al. (2007a), proton accelaration was assumed to occur at distances only (sim 20-30 ) Scwarzchild radii from the black hole (e.g. Liu et al. 2006). The particles would then diffuse away from the Sgr A* through the magnetized turbulent ISM ? , until possibly colliding with the dense molecular gas in the circumnuclear disk.
Berger, E., Fox, D. B., Price, P. A., Nakar, E., Gal‐Yam, A., Holz, D. E., & Songaila, A. (2007). A New Population of High‐Redshift Short‐Duration Gamma‐Ray Bursts. The Astrophysical Journal.
B. Impulsive stage- protons and electrons are accelerated and radio waves, hard x-rays and gamma rays are
Of all the galaxies in the entire Universe these are the closest to our galactic system. About 170,000 light-years away from the Milky Way galaxy lie the Large Magellanic Cloud. With only 15 billion young bright stars, it is just one-quarter the size of our own galaxy. During the winter of 1987, a Canadian astronomer, Ian Shelton, spotted the first naked eye supernova since 1604, the result of a massive explosion. No more exciting and scientifically significant event has occurred over the last decade in science than Supernova 1987A, as it is known. Photographs taken on the night of February 23, 1987, of the Large Magellanic Cloud, a companion galaxy to our own Galaxy, at Canada's southern hemisphere observatory at La Silla, Chile, and at the Siding Springs Observatory in Australia, revealed a 6th-magnitude object where only 12th-magnitude blue supergiant stars had been observed before. Scientists believe that the progenitor of Supernova 1987A is a typical blue supergiant of spectral type B3. Spectra taken in 1977 do not suggest anything unusual happening in the outer layers of the star prior to undergoing the supernova outburst. This is not surprising since the real changes were occurring deep inside in a relatively tiny portion of the star's radius. The Large Cloud is quite important because it is the location of this Supernova 1987A, the exploded star that for a time shone brightly but that is now dim and dead.
Particle physics deals with the study of the smallest, most intricate objects of nature. Examples of these particles include the atom (10-10 m), nucleus (10-14 m), and quarks (less than 10-19 m) (Ekeren, 2013). These fundamental particles trace back to the moments after the Big Bang. As a way to explore how our universe evolved to what is in existence now, the European Organization for Nuclear Research, abbreviated as CERN, built the world’s most powerful particle accelerator during 1998 and 2008 – the Large Hadron Collider, or, the LHC. (STFC, n.d.). The LHC is the last element of the chain of accelerator complex present in CERN. The accelerator complex consists of a sequence of machines with increasingly higher energies (CERN, 2009). In the LHC, each particle beam injected is accelerated up to 7 TeV (electronvolt) of energy. The LHC is composed of different experimental halls which are intended for different purposes which will be discussed further in this paper. Physicists believes that the energy density and temperature data gathered from the collision experiments at the LHC will be able to demonstrate what existed within the moments after the Big Bang, to provide an example for its data’s use. They recreate and simulate these experiments inside the 27 km accelerator through beam collision of beams of high-energy protons or ions which travel at the speed of light, or 300 million meters per second (STFC, n.d.; US/LHC, 2012).
...is its anti particle. When these particles appear, they will shortly annihilate each other because they are exact opposites (UCR). However, if one of these particle pairs appears at the event horizon of a black hole, the gravity from the black hole will tear the pair of particles apart. The normal particle will have just enough energy to escape the black hole. The particles escapes as Hawking Radiation. On the other hand, the anti particle gets sucked into the black hole. Since the anti particle has a negative mass, it actually decreases the mass of the black hole. The effects of Hawking radiation are generally negated by the fact that black hole sucks more in than it radiates (SST). But eventually it will not have anything more to suck in and start to lose mass. And at the end of its life, it will become unstable and suddenly release all of its mass in a big bang...
In 2010, astronomers announced the discovery of two vast- and very mysterious-bubbles of gamma-ray. these structures are enormous balloons of energetic gamma rays emanating from the center of our galaxy they are Two towering bubbles that stretch tens of thousands of light above and below our galaxy. The new portain,described in a paper that has been accepted for on analysis like two 30,000 light year tall incandescent bulbs screwed into the center of the galaxy, the source of these bubbles are mysterious as ever.
In modern day physics, Black Holes have dominated the spotlight for quite some time. While the concept has answered many questions, it has also introduced hundreds more. There is believed to be a black hole at the center of our galaxy, the Milky Way galaxy. Black holes were first proven to exist in the 1970’s when a few scientists identified a black hole called Cygnus X-1. Since then, an intense amount of study has been dedicated to discovering the various properties of black holes.
Conway, A, Coleman, R. 2003, A beginner’s guide to the Universe, Press Syndicate, The University of Cambridge, United Kingdom.
Tyler, Pat. Supernova. NASA’s Heasarc: Education and Public Information. 26 Jan. 2003. 22 Nov. 2004
Evidence that the heavens house a previously unknown type of black hole was reported by scientists yesterday. Data from NASA’s Chandra X-Ray Observatory revealed a hole was some 600 light-years from the center of the starburst galaxy M82. The brightness of the x-ray source indicates that this moon-size hole has the mass of at least 500 suns, making it intermediate between stellar black holes and the supermassive black holes found at the centers of galaxies. “This opens a whole new field of research,” said Martin Ward, a lead author on one of three papers to be published on the subject. “No one was sure that such black holes existed, especially outside the centers of galaxies.”
Galper, A. M., et al. "Characteristics of the GAMMA-400 gamma-ray telescope for searching for dark matter signatures." Bulletin of the Russian Academy of Sciences: Physics 77.11 (2013): 1339-1342.
Travelling at the speed of light, cosmic rays can penetrate through the human body and alter DNA. This poses numerous health issues, such as the increased rick of cancer development. Thankfully, the earth’s atmosphere and magnetic field is structured in such a way that helps prevent cosmic rays from fully reaching the surface of the earth (De Nolfo). Because cosmic rays are charged, when they come into contact with the Earth’s magnetic field, a large majority of them are repelled or deflected away. Often times, the subatomic charged particles are redirected to the poles and proceed to interact with the gases in the Earth’s upper atmosphere; this interaction gives rise to Aurora (Telescope Array Project). But this deflection and protection from cosmic rays due to a magnetic field is not unique to Earth. Other planets have magnetic fields and therefore will also deflect incoming cosmic rays. This fact makes it quite challenging to determine a cosmic ray’s origin (“Primary Cosmic
There is quite a bit of history involving gamma ray radiation. We have learned that gamma rays that come from space are mostly absorbed by Earth's atmosphere, which means that gamma ray astronomy couldn’t be developed until we could study it from the outside (Mattson, Barbra). The first gamma ray telescope was made and sent into space in 1961, as it turns out it picked up less than 100 gamma ray photons that seemed to be coming from all directions in the universe (Mattson, Barbra). The first successful detection of gamma ray radiation in space was in 1967 by the gamma ray detector aboard the OSO-3 satellite, it detected 621 dealings with gamma rays (Mattson, Barbra). Later on the SAS-2 and COS-B satellites provided more gamma ray radiation data (Mattson, Barbra). The data from these satellites confirmed earlier data found on the gamma rays background, it also produced the first detailed map of the sky at gamma ray wave le...
PaP Particle and Astroparticle Physics (M.Sc.) offered by the University of Amsterdam "prepares researchers for excellent independent research or a contri...