x ray astronomy

[ابن القيم]

السلام عليكم
مرحبا بكم اخواني في الله
باذن الله سوف أضع بين أيديكم بحث عن علم الفلك في x ray ( أشعه اكس) ولكن اعذروني اخواني في الله فهو باللغه الانجليزيه لانه لم يسعفني الوقت لترجمته .
اخواني هذا البحث ليس منقول فقد قمت بتجميعه من عده كتب ومواقع علميه فهو حصري للمنتديات العلميه
أنا سأضع جزء منه ان أردتم أن أضعه كله فسوف أضعه باذن الله
1   Introduction:
      X-rays were first observed and documented in 1895 by Wilhelm Conrad Röntgen, a German scientist who found them quite by accident when experimenting with vacuum tubes. A week later, he took an X-ray photograph of his wife's hand which clearly revealed her wedding ring and her bones. Röntgen called it "X" to indicate it was an unknown type of radiation. In June 1990, the United States launched a new German-built satellite to record X-rays from the sky. This program was named Röntgen Satellite in his honor.
X-ray astronomy is a relatively new science as we have needed satellites to do it; these have only been around since the 1950's. The Earths' atmosphere blocks X-rays from reaching the Earths' surface. This is because the atmosphere contains water which is opaque to X-rays.
This picture shows how different wavelengths of electromagnetic radiation ("light") are absorbed by the atmosphere. Therefore we
need satellites to be able to do any X-ray astronomy
2   How do we observing X ray?
      To observe X-rays from the sky, the X-ray detectors must be flown above most of the Earth's atmosphere
There are at present three methods of doing so:
2.1   Rocket flights:
     A detector is placed in the nose cone section of the Rocket and launched above the atmosphere. It is very Short duration where it takes a few minutes above the Atmosphere before the rocket falls back to Earth
2.2   Balloons
    Balloon flights can carry instruments to altitudes of 35 kilometers above sea level, where they are above the Earth's atmosphere. Unlike a rocket where data are collected during a few minutes, balloons are able to stay for much longer. However, even at such altitudes, much of the X-ray spectrum is still absorbed. X-rays with energies less than 35 keV cannot reach balloons. One of the recent balloon-borne experiments was called the High Resolution Gamma-ray and Hard X-ray Spectrometer. It was launched from the Antarctic where steady winds carried the balloon on a circumpolar flight lasting for almost two months.
والختام السلام .

[ع.ف....عالم فيزياء]

أرجو ان تكمل البحث سيدي الفاضل لأنه فعلا رائع ، وبه معلومات جديدة..............
لكن:-

QUOTE

There are at present three methods of doing so:

الطريقة الثالثة لم تذكرها....................

[ابن القيم]

السلام عليكم
أسعدني مرورك أخي ع.ف....عالم فيزياء
 الطريقه الثالثه هي استخدام الاقمار الصناعيه وسوف اتكلم عنها بشيء من التفصيل باذن الله ولكن باللغه الانجليزيه.

[ابن القيم]

2.3   Satellites
     A detector is placed on a satellite which is taken up to an orbit well above the Earth's atmosphere. Unlike balloons, instruments on satellites are able to observe the full range of the X-ray spectrum.
By 1967 there more groups involved in X-ray astronomy, and more than thirty Sources had been found. Major advances in the field began in the 1970s with the use of satellites Equipped with X-ray detectors. The first of these, Uhuru, was launched in 1970. In 1978, NASA’s Einstein X-ray observatory was the first large focusing X-ray telescope to be placed in orbit. The Einstein X-ray telescope produced high-resolution images and accurate locations for Thousands of cosmic X-ray sources. This and later missions have observed X rays from ordinary stars, white dwarf stars, neutron stars, Black holes, interstellar shock waves produced by stellar explosions, the Nuclei of galaxies, and hot gas in intergalactic space. The x rays detected by X-ray astronomers, must be produced by high-energy particles. An X-ray image of the sky can look markedly different from an optical image.X-ray images reveal hot spots in the universe: regions where particles have been energized or raised to very high temperatures by phenomena Such as strong magnetic fields, violent explosions, or intense gravitational forces.
 The source of X rays from these stars is a hot gaseous upper atmosphere, or corona, that has been heated to temperatures of millions of degrees Celsius. Young stars less than a hundred million years old are observed to have an X-ray output a thousand times more than that of the sun. This suggests that the X-radiation from the young sun could have been much stronger than it is today.
There are two major X-ray Satellites currently in orbit taking data and producing exciting science.
2.3.1   XMM-NEWTON :
      XMM-NEWTON was launched on 10th December 1999 by the first commercial Ariane-V launch. It is one of the European Space Agency's cornerstone missions and was designed to be a satellite which could perform high quality and high sensitivity X-ray spectroscopy.
2.3.2   CHANDRA:
      The CHANDRA X-ray Observatory was launched on the 23rd July 1999 by the Space Shuttle Columbia. It was designed to provide high resolution imaging of X-ray sources; as opposed to XMM-NEWTON which has better spectral resolution but bade imaging capabilities. It was the follow up to the EINSTEIN observatory.

[فلكينو]

السلام عليكم ....

نشكرك جزيل الشكر اخى الكريم ابن القيم على جعل الموضوع حصرى للمنتديات العلمية و تابع عملك نحن متابعين

و لكم جزيل الشكر .....  '>

[ابن القيم]

أسعدني مرورك أخي فلكينو
الان سوف نتكلم عن بعض مصادر ال  x ray
3   THE X-RAY SOURCES
     The brightest X-ray sources in the sky are associated with the end phases of stellar evolution.
The X-ray emission from these collapsed stars is billions of times greater than that from the sun. Combined observations with optical and X-ray telescopes have demonstrated that these X-ray sources are members of binary systems in which matter streams from a normal star onto a nearby  collapsed star with an intense gravitational field.
 For examples of X-ray sources
3.1   Black Holes    
     Stellar mass black holes are formed when a massive star explodes in a Supernova. A black hole is something that is so massive that even light cannot escape its surface. When astronomers talk about a black hole, they usually mean the Schwarzschild radius, beyond which nothing can escape. As no light can escape from a black hole we cannot see them directly, as it is very massive, its gravity pulls things in. Most things in space spin - for example galaxies, stars and planets - and so when things are falling towards the black hole they begin to swirl around it. Different parts of the material orbit around the black hole a different speeds and so they rub against one-another and become hot from friction. As the material is moving very fast by the time it is close to the black hole it is very hot and so emits X-rays.
Larger black holes are found at the centre of most galaxies, these as millions if not billions of times as massive as our Sun. They are too far away to be seen directly.
3.2    X-ray Binaries
     As the name suggests these are binary systems which emit large amounts of X-rays. These were among the first X-ray sources. Sco X-1 and Cygnus X-1 were the first X-ray sources to be discovered in the constellations of Scorpius and Cygnus respectively and they are both X-ray binaries. There are two different types of X-ray Binaries - High Mass (HMXB) and Low Mass (LMXB), and they have different properties
High Mass: X-ray Binaries from two stars of different mass which are in orbit around each other. The more massive one evolves faster and reaches the end of its life first, after a few million years or so. It becomes a giant and the outer layers are lost to its companion. Then it explodes in a supernova leaving behind either a neutron star or a black hole. This can disrupt the binary system, but if the star that exploded was less massive than its companion when it exploded they the systems will remain in tact, though the orbits may be more eccentric. The companion star then comes to the end of its life and swells to form a giant. It then looses its outer layers onto the neutron star or black hole. This is the HMXB phase.
The material forms an accretion disc around the compact object, which heats up because of friction. This heating cause the X-ray emission. Eventually the companion star comes to the end of its life, leaving a neutron star/black hole depending on the initial masses of the stars. Cygnus X-1 is this type of X-ray Binary.
Low Mass: in this kind of binary system the mass transfer on to the compact object is much slower and more controlled. This mass transfer can spin up a neutron star so that it is a millisecond pulsar, spinning thousands of times a second. Low Mass X-ray Binaries tend to emit X-rays in bursts and there could be many more present in our galaxy than we see, but which are currently switched off. They also tend to have softer spectra (they emit lower energy X-rays), whereas the HMXB's have harder spectra (more energetic X-rays).