Astronomy Ch 20 The Universe
... precise observations of very faint and distant objects. These observations depend on technology, such as telescopes ...
... precise observations of very faint and distant objects. These observations depend on technology, such as telescopes ...
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- EPJ Web of Conferences
... Figure 2. (a) Mean metallicity, and (b) metallicity dispersion, [Fe/H], vs. system absolute magnitude, MV ,total , for the dwarf galaxy satellites of the Milky Way and the massive globular cluster Cen. Figure from [10]. ...
... Figure 2. (a) Mean metallicity, and (b) metallicity dispersion, [Fe/H], vs. system absolute magnitude, MV ,total , for the dwarf galaxy satellites of the Milky Way and the massive globular cluster Cen. Figure from [10]. ...
Dark Energy and Cosmic Sound
... This signature has a size that we can calculate accurately. Measuring this as an angle allows us to infer the distance to a sample of galaxies. Measuring accurate distances is a key way to study the acceleration of the Universe and the properties of dark energy. In the last 4 years, astronomers have ...
... This signature has a size that we can calculate accurately. Measuring this as an angle allows us to infer the distance to a sample of galaxies. Measuring accurate distances is a key way to study the acceleration of the Universe and the properties of dark energy. In the last 4 years, astronomers have ...
Chapter 7: The Galaxy, structure and content File
... appear for stars of all ages. (And these are clumps only in velocity space, not in real space.) The idea that there are groups of stars at similar velocities is itself not new—it actually dates from the early proper motion measurements of nearly a century ago. But these ‘streams’ have generally been ...
... appear for stars of all ages. (And these are clumps only in velocity space, not in real space.) The idea that there are groups of stars at similar velocities is itself not new—it actually dates from the early proper motion measurements of nearly a century ago. But these ‘streams’ have generally been ...
Lecture 5
... properly corrected for, this dust absorption can lead to erroneous luminosity determinations. Finally, it has been very difficult to detect Cepheids in distant galaxies from the ground: Earth's fluctuating atmosphere makes it impossible to separate these stars from the diffuse light of their host ga ...
... properly corrected for, this dust absorption can lead to erroneous luminosity determinations. Finally, it has been very difficult to detect Cepheids in distant galaxies from the ground: Earth's fluctuating atmosphere makes it impossible to separate these stars from the diffuse light of their host ga ...
Study of the X-ray Source Population and the Dark Matter
... spatial and time resolution, the Wide Field Imager of the Athena Xray Observatory will make it possible to study X-ray sources down to very low flux limits. In Draco dSph, e.g., we will be able to observe X-ray sources with luminosities down to 1031 erg/s with 1000 to 2000 counts in 10 ksec, allowin ...
... spatial and time resolution, the Wide Field Imager of the Athena Xray Observatory will make it possible to study X-ray sources down to very low flux limits. In Draco dSph, e.g., we will be able to observe X-ray sources with luminosities down to 1031 erg/s with 1000 to 2000 counts in 10 ksec, allowin ...
06-01Distance_Ladder
... If you know the Earth-Mars distance, Kepler’s law RE3 = RM3 TE2 TM2 now lets you figure out the radius of Earth’s orbit. ...
... If you know the Earth-Mars distance, Kepler’s law RE3 = RM3 TE2 TM2 now lets you figure out the radius of Earth’s orbit. ...
Messier 87
Messier 87 (also known as Virgo A or NGC 4486, and generally abbreviated to M87) is a supergiant elliptical galaxy in the constellation Virgo. One of the most massive galaxies in the local universe, it is notable for its large population of globular clusters—M87 contains about 12,000 compared to the 150-200 orbiting the Milky Way—and its jet of energetic plasma that originates at the core and extends outward at least 1,500 parsecs (4,900 light-years), travelling at relativistic speed. It is one of the brightest radio sources in the sky, and is a popular target for both amateur astronomy observations and professional astronomy study.French astronomer Charles Messier discovered M87 in 1781, cataloguing it as a nebulous feature while searching for objects that would confuse comet hunters. The second brightest galaxy within the northern Virgo Cluster, M87 is located about 16.4 million parsecs (53.5 million light-years) from Earth. Unlike a disk-shaped spiral galaxy, M87 has no distinctive dust lanes. Instead, it has an almost featureless, ellipsoidal shape typical of most giant elliptical galaxies, diminishing in luminosity with distance from the centre. Forming around one sixth of M87's mass, the stars in this galaxy have a nearly spherically symmetric distribution, their density decreasing with increasing distance from the core. At the core is a supermassive black hole, which forms the primary component of an active galactic nucleus. This object is a strong source of multiwavelength radiation, particularly radio waves. M87's galactic envelope extends out to a radius of about 150 kiloparsecs (490,000 light-years), where it has been truncated—possibly by an encounter with another galaxy. Between the stars is a diffuse interstellar medium of gas that has been chemically enriched by elements emitted from evolved stars.