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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Chandra X-ray Observatory | 2/3 | https://en.wikipedia.org/wiki/Chandra_X-ray_Observatory | reference | science, encyclopedia | 2026-05-05T12:57:48.807471+00:00 | kb-cron |
The first light image, of supernova remnant Cassiopeia A, gave astronomers their first glimpse of the compact object at the center of the remnant, probably a neutron star or black hole. In the Crab Nebula, another supernova remnant, Chandra showed a never-before-seen ring around the central pulsar and jets that had only been partially seen by earlier telescopes. The first X-ray emission was seen from the supermassive black hole, Sagittarius A*, at the center of the Milky Way. Chandra confirmed that X-rays in O-type stars are generated through plasma shocks embedded in their wind. Chandra found much more cool gas than expected spiraling into the center of the Andromeda Galaxy. Pressure fronts were observed in detail for the first time in Abell 2142, where clusters of galaxies are merging. The earliest images in X-rays of the shock wave of a supernova were taken of SN 1987A. Chandra showed for the first time the shadow of a small galaxy as it is being cannibalized by a larger one, in an image of Perseus A. A new type of black hole was discovered in galaxy M82, mid-mass objects purported to be the missing link between stellar-sized black holes and super massive black holes. X-ray emission lines were associated for the first time with a gamma-ray burst, Beethoven Burst GRB 991216. High school students, using Chandra data, discovered a neutron star in supernova remnant IC 443. Observations by Chandra and BeppoSAX suggest that gamma-ray bursts occur in star-forming regions. Chandra data suggested that RX J1856.5-3754 and 3C58, previously thought to be pulsars, might be even denser objects: quark stars. These results are still debated. Sound waves from violent activity around a super massive black hole were observed in the Perseus Cluster (2003). TWA 5B, a brown dwarf, was seen orbiting a binary system of Sun-like stars. Nearly all stars on the main sequence are X-ray emitters. The X-ray shadow of Titan was seen when it transited the Crab Nebula. X-ray emissions from materials falling from a protoplanetary disc into a star. Hubble constant measured to be 76.9 km/s/Mpc using Sunyaev-Zel'dovich effect. 2006 Chandra found strong evidence that dark matter exists by observing super cluster collision. 2006 X-ray emitting loops, rings and filaments discovered around a super massive black hole within Messier 87 imply the presence of pressure waves, shock waves and sound waves. The evolution of Messier 87 may have been dramatically affected. Observations of the Bullet Cluster put limits on the cross-section of the self-interaction of dark matter. "The Hand of God" photograph of PSR B1509-58. Jupiter's x-rays coming from poles, not auroral ring. A large halo of hot gas was found surrounding the Milky Way. Extremely dense and luminous dwarf galaxy M60-UCD1 observed. On January 5, 2015, NASA reported that CXO observed an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*, the supermassive black hole in the center of the Milky Way galaxy. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*, according to astronomers. In September 2016, it was announced that Chandra had detected X-ray emissions from Pluto, the first detection of X-rays from a Kuiper belt object. Chandra had made the observations in 2014 and 2015, supporting the New Horizons spacecraft for its July 2015 encounter. In September 2020, Chandra reportedly may have made an observation of an exoplanet in the Whirlpool Galaxy, which would be the first planet discovered beyond the Milky Way. In April 2021, NASA announced findings from the observatory in a tweet saying "Uranus gives off X-rays, astronomers find". The discovery would have "intriguing implications for understanding Uranus" if it is confirmed that the X-rays originate from the planet and are not emitted by the Sun.
== Technical description ==
Unlike optical telescopes which possess simple aluminized parabolic surfaces (mirrors), X-ray telescopes generally use a Wolter telescope consisting of nested cylindrical paraboloid and hyperboloid surfaces coated with iridium or gold. X-ray photons would be absorbed by normal mirror surfaces, so mirrors with a low grazing angle are necessary to reflect them. Chandra uses four pairs of nested mirrors, together with their support structure, called the High Resolution Mirror Assembly (HRMA); the mirror substrate is 2 cm-thick glass, with the reflecting surface a 33 nm iridium coating, and the diameters are 65 cm, 87 cm, 99 cm and 123 cm. The thick substrate and particularly careful polishing allowed a very precise optical surface, which is responsible for Chandra's unmatched resolution: between 80% and 95% of the incoming X-ray energy is focused into a one-arcsecond circle. However, the thickness of the substrate limits the proportion of the aperture which is filled, leading to the low collecting area compared to XMM-Newton. Chandra's highly elliptical orbit allows it to observe continuously for up to 55 hours of its 64-hour orbital period. At its furthest orbital point from Earth, Chandra is one of the most distant Earth-orbiting satellites. This orbit takes it beyond the geostationary satellites and beyond the outer Van Allen belt. With an angular resolution of 0.5 arcsecond (2.4 μrad), Chandra possesses a resolution over 1000 times better than that of the first orbiting X-ray telescope. CXO uses mechanical gyroscopes, which are sensors that help determine what direction the telescope is pointed. Other navigation and orientation systems on board CXO include an aspect camera, Earth and Sun sensors, and reaction wheels. It also has two sets of thrusters, one for movement and another for offloading momentum.