User:Javierz967/sandbox/MAXI(ISS Experiment)

MAXI(Monitor of All-Sky X-ray Image) is comprised of two X-ray slit cameras and was mounted on the International Space Station(ISS) in 2009 in order to detect X-ray transient events, emissions of X-rays from celestial objects, and monitor fluctuations on known X-ray sources. MAXI can scan the whole sky in the time it takes the International Space Station to orbit the Earth(96 minutes). The cameras used on MAXI are the Gas Slit Camera(GSC) and the Solid-state Slit Cameras(SSC) which are both aligned to observe the horizontal and zenith(directly above the observer on Earth) directions. MAXI has also discovered 6 black holes from 2009 to 2015 as well as other X-ray phenomena.

Purpose of Experiment

In the past, we have had All Sky Monitor's(ASMs), artificial satellites that monitor X-ray sources, and satellites that focused on detecting sources of X-rays in our sky but MAXI will instead monitor changes in X-rays from celestial objects that are farther away from our galaxy and with a greater field of view. Compared to older ASMs MAXI's equipment is more than 20 times as sensitive meaning it is able to detect even slighter changes in X-rays out in our galaxy. When it detects a flare up or any drastic change in X-rays MAXI will send this information through the internet so observers can immediately discuss and see the evolution of these phenomena. MAXI will record this data and catalog all this data in order for astronomers or researchers to create long term studies of X-ray novae, X-ray transients, and gamma-ray bursts.

X-ray Phenomena

Like visible light, an X-ray is an electromagnetic wave but unlike visible light it has a much shorter wavelength. In our universe there are many X-ray phenomena that are generated from high energy particles and hot gases and many of these are thought to be related to neutron stars and blackholes, which are both exploding matter that release X-rays. These are some of the phenomena that MAXI will observe through its expedition. The table below will list the type of X-ray phenomena that MAXI will monitor as well as a description of the phenomena.

Type of X-ray Phenomena	Description
Black hole	A black hole is created when a star collapses in on itself which creates a space where gravity is so strong that even visible light is unable to escape. This means that we are unable to see black holes with the naked eye so we need to use special telescopes and cameras to view them.These cameras help astronomers and researchers create catalogs and studies that will help strengthen our understanding of black holes.
X-ray Nova	A sudden appearance of an X-ray source that peaks in a few days but then slowly after a period of months it disperses. They most commonly occur when stored gas rushes out of a compact object.(i.e.Black holes or neutron stars)
X-ray Transient	Celestial objects emit X-ray's and many of these emissions are only temporary. These emissions are constantly changing and some disappear completely while some return after some time.
Gamma-ray Burst	These bursts are extremely energetic explosions and they are some of the strongest and brightest in our universe. They can last from less than a second to several hours. They are thought to originate from the creation of black holes.
Neutron Star	They are created similarly to that of a black hole(a star "dies" and collapse in on itself) but unlike black holes all the electrons and protons condense and form neurons and if they are within 1 and 3 solar masses a neutron star will be born

Machinery

MAXI is a device that is a part of the Japanese Experiment Module and it was developed by the Japan Aerospace Exploration Agency (JAXA), Tsukuba, Japan. It was installed with two types of slit cameras.

Gas Slit Camera(GSC):

The Gas Slit Camera(GSC) is the main X-ray camera on MAXI. It scans the entire sky each time the International Space Station orbits the Earth. It is made of six conventional slit cameras, but these cameras have a disadvantage because of their limited slit area. This limited area makes the camera better suited to detect faint signals. This heightened sensitivity is attributed to the use of Xenon gas which makes a great detector for X-rays. The six cameras that comprise the GSC were assembled and placed(on ISS) to face two fields of view(FOVs); these were the Earth's horizon and the zenith direction(directly above the observer on earth). These FOVs are crucial as in the time it takes the International Space Station to fully orbit the earth the X-ray transient has now been monitored twice.

Solid-state Slit Camera(SSC):

The Solid-state slit Camera is also mounted to scan the sky on the horizontal and zenith direction. The Solid-state Camera is composed of two Solid-state Camera Units(SSCUs). The SSCUs are made of aluminum, in particular the surface of these units are made of black inorganic anodized aluminum alloys. This design choice was crucial as the alloy will now aid in the suppression of light reflection. The Solid-state Camera employs two sensors that view X-ray sky using charge-coupled devices (CCDs). These charge-coupled devices are very sensitive to both infrared and optical light, both of which would reduce its performance in detecting X-rays. This issue was fixed with the implementation of a 0.2μm(micrometer) thick coat of aluminum.

Discoveries

Since 2009 MAXI has discovered 13 black holes(April 10, 2020). MAXI has also made many discoveries that have helped astronomers and other researchers better understand our universe. One of its major discoveries was an X-ray source that was determined to be a black hole, which had a mass that was several times then that of our Sun. It was then named MAXI J1820+070 and with the help of Neutron star Interior Composition Explorer(NICER) we now have a better understanding on how black holes consume material from nearby stars.MAXI has also made unexpected discoveries like a flare star that was millions of times stronger than that our sun. Because of MAXI's long expedition it has made research on long term X-ray fluctuations in neutron star binaries very efficient.