X-ray astronomy

X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites.

"Two years later, he proposed an experimental program in which a rocket might be instrumented to explore the upper atmosphere, including detection of ultraviolet radiation and X-rays at high altitudes".

[2] In the late 1930s, the presence of a very hot, tenuous gas surrounding the Sun was inferred indirectly from optical coronal lines of highly ionized species.

[6] An Aerobee 150 rocket launched on June 19, 1962 (UTC) detected the first X-rays emitted from a source outside our solar system[7][8] (Scorpius X-1).

[10] Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002.

The interstellar medium consists of an extremely dilute (by terrestrial standards) mixture of ions, atoms, molecules, larger dust grains, cosmic rays, and (galactic) magnetic fields.

On July 21, 1964, the Crab Nebula supernova remnant was discovered to be a hard X-ray (15–60 keV) source by a scintillation counter flown on a balloon launched from Palestine, Texas, United States.

[14] The high-energy focusing telescope (HEFT) is a balloon-borne experiment to image astrophysical sources in the hard X-ray (20–100 keV) band.

Rather than using a grazing-angle X-ray telescope, HEFT makes use of a novel tungsten-silicon multilayer coatings to extend the reflectivity of nested grazing-incidence mirrors beyond 10 keV.

The detectors consisted of 23-mm thick × 51-mm diameter CsI(Tl) crystals mounted via plastic light tubes to photomultipliers.

Dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid acts to maintain a magnetic field.

[24] In addition, there is no radio emission, and the visible continuum is roughly what would be expected from a hot plasma fitting the observed X-ray flux.

[citation needed] The mechanism triggering the different temporal behavior observed between the classical SGXBs and the recently discovered supergiant fast X-ray transients (SFXT)s is still debated.

[34] A rocket flight on that date briefly calibrated its attitude control system when a star sensor pointed the payload axis at Capella (α Aur).

[3] Experiments with instruments aboard Skylab and Copernicus have been used to search for soft X-ray emission in the energy range ~0.14–0.284 keV from stellar coronae.

[36] With the operation of the Einstein observatory, X-ray emission was recognized as a characteristic feature common to a wide range of stars covering essentially the whole Hertzsprung-Russell diagram.

[36] The Einstein initial survey led to significant insights: To fit the medium-resolution spectrum of UX Arietis, subsolar abundances were required.

[3] Beyond spectral type M5, the classical αω dynamo can no longer operate as the internal structure of dwarf stars changes significantly: they become fully convective.

[3] However, the current popular hypothesis involves a merger of a close binary system in which the orbital angular momentum of the companion is transferred to the primary.

These three structures around Eta Carinae are thought to represent shock waves produced by matter rushing away from the superstar at supersonic speeds.

"The Chandra image contains some puzzles for existing ideas of how a star can produce such hot and intense X-rays," says Prof. Kris Davidson of the University of Minnesota.

The United States Air Force Academy (USAFA) is the home of the US's only undergraduate satellite program, and has and continues to develop the FalconLaunch sounding rockets.

Magnetic fields are ubiquitous among stars, yet we do not understand precisely why, nor have we fully understood the bewildering variety of plasma physical mechanisms that act in stellar environments.

Evolution of these closed magnetic structures in response to various photospheric motions over different time scales (convection, differential rotation, meridional circulation) somehow leads to the CME.

[56] Small-scale energetic signatures such as plasma heating (observed as compact soft X-ray brightening) may be indicative of impending CMEs.

[56] "Relating the sigmoids at X-ray (and other) wavelengths to magnetic structures and current systems in the solar atmosphere is the key to understanding their relationship to CMEs.

Observations made by Chandra indicate the presence of loops and rings in the hot X-ray emitting gas that surrounds Messier 87.

[citation needed] NASA's Swift Gamma-Ray Burst Mission satellite was monitoring Comet Lulin as it closed to 63 Gm of Earth.

This causes the solar wind to light up with X-rays, and that's what Swift's XRT sees", said Stefan Immler, of the Goddard Space Flight Center.

This interaction, called charge exchange, results in X-rays from most comets when they pass within about three times Earth's distance from the Sun.

X-rays start at ~0.008 nm and extend across the electromagnetic spectrum to ~8 nm, over which the Earth's atmosphere is opaque .
NRL scientists J. D. Purcell, C. Y. Johnson, and Dr. F. S. Johnson are among those recovering instruments from a V-2 used for upper atmospheric research above the New Mexico desert. This is V-2 number 54, launched January 18, 1951, (photo by Dr. Richard Tousey, NRL).
A launch of the Black Brant 8 Microcalorimeter (XQC-2) at the turn of the century is a part of the joint undertaking by the University of Wisconsin–Madison and NASA 's Goddard Space Flight Center known as the X-ray Quantum Calorimeter (XQC) project.
The Crab Nebula is a remnant of an exploded star. This image shows the Crab Nebula in various energy bands, including a hard X-ray image from the HEFT data taken during its 2005 observation run. Each image is 6′ wide.
Navy Deacon rockoon photographed just after a shipboard launch in July 1956.
One of the mirrors of XRISM made of 203 foils
Andromeda Galaxy – in high-energy X-ray and ultraviolet light (released 5 January 2016).
This light curve of Her X-1 shows long term and medium term variability. Each pair of vertical lines delineate the eclipse of the compact object behind its companion star. In this case, the companion is a two solar-mass star with a radius of nearly four times that of the Sun. This eclipse shows us the orbital period of the system, 1.7 days.
This ROSAT PSPC false-color image is of a portion of a nearby stellar wind superbubble (the Orion-Eridanus Superbubble ) stretching across Eridanus and Orion .
Ulysses' second orbit: it arrived at Jupiter on February 8, 1992, for a swing-by maneuver that increased its inclination to the ecliptic by 80.2 degrees.
X-Rays from Pluto
Images released to celebrate the International Year of Light 2015
( Chandra X-Ray Observatory ).
A Chandra X-ray image of the Cluster of newly formed stars in the Orion Nebula .
Classified as a Peculiar star , Eta Carinae exhibits a superstar at its center as seen in this image from Chandra X-ray Observatory . Credit: Chandra Science Center and NASA.
A solar cycle : a montage of ten years' worth of Yohkoh SXT images, demonstrating the variation in solar activity during a sunspot cycle, from after August 30, 1991, at the peak of cycle 22 , to September 6, 2001, at the peak of cycle 23 . Credit: the Yohkoh mission of Institute of Space and Astronautical Science (ISAS, Japan) and NASA (US).
Image of Comet Lulin on 28 January 2009, when the comet was 99.5 million miles from Earth and 115.3 million miles from the Sun, from Swift . Data from Swift's Ultraviolet/Optical Telescope is shown in blue and green, and from its X-Ray Telescope in red.