AY5 Homework for Quiz 4: Spring 2015
... __X__ it is “cold” (i.e. moves slowly compared to the speed of light) __X__ it does not readily interact directly with photons or other matter (i.e. it has a small cross-‐section for interations) _ ...
... __X__ it is “cold” (i.e. moves slowly compared to the speed of light) __X__ it does not readily interact directly with photons or other matter (i.e. it has a small cross-‐section for interations) _ ...
PH607 – Galaxies
... 7.2 Clusters of Galaxies Clusters are systems a few Mpc across, typically containing at least 50-100 luminous galaxies within the central 1 Mpc Clusters are gravitationally bound Clusters are filled with hot X-ray gas Only ~20% of galaxies live in clusters, most live in groups or in the “fi ...
... 7.2 Clusters of Galaxies Clusters are systems a few Mpc across, typically containing at least 50-100 luminous galaxies within the central 1 Mpc Clusters are gravitationally bound Clusters are filled with hot X-ray gas Only ~20% of galaxies live in clusters, most live in groups or in the “fi ...
Scientists confirm most distant galaxy ever
... Besides breaking the distance record, astronomers find the new galaxy exciting because it appears to produce stars at an unusually high rate, said lead study author Steven Finkelstein, assistant professor of astronomy at the University of Texas at Austin. Star-formation rate is measured by how much ...
... Besides breaking the distance record, astronomers find the new galaxy exciting because it appears to produce stars at an unusually high rate, said lead study author Steven Finkelstein, assistant professor of astronomy at the University of Texas at Austin. Star-formation rate is measured by how much ...
21structure1i
... We can use spectroscopy and photometry to get the spectral type and the apparent magnitude (m) of a star We can estimate the absolute magnitude (M) from the spectral type With the two magnitudes we can get the distance: ...
... We can use spectroscopy and photometry to get the spectral type and the apparent magnitude (m) of a star We can estimate the absolute magnitude (M) from the spectral type With the two magnitudes we can get the distance: ...
Lecture17
... Distant objects (galaxies) move away from us faster and faster, turning redder and dimmer. When they reach the speed of light c , they turn black. That is the horizon. By looking farther out , we are also looking back in time. The horizon corresponds to the Big Bang. How close can we look back towar ...
... Distant objects (galaxies) move away from us faster and faster, turning redder and dimmer. When they reach the speed of light c , they turn black. That is the horizon. By looking farther out , we are also looking back in time. The horizon corresponds to the Big Bang. How close can we look back towar ...
Molecular gas in the host galaxy of a quasar at redshift z 5 6.42
... Figure 1 CO detection in J1148þ5251. a, VLA CO(3-2) emission detected at 46.6149 GHz (z ¼ 6.418, bandwith: 50 MHz, Dz ¼ 0.008). b, Co-added VLA emission in the neighbouring line-free channels. The (1j) noise in both images is 0.057 mJy beam21 and contours are plotted at 20.1, 0.1, 0.2, 0.3, 0.4 and ...
... Figure 1 CO detection in J1148þ5251. a, VLA CO(3-2) emission detected at 46.6149 GHz (z ¼ 6.418, bandwith: 50 MHz, Dz ¼ 0.008). b, Co-added VLA emission in the neighbouring line-free channels. The (1j) noise in both images is 0.057 mJy beam21 and contours are plotted at 20.1, 0.1, 0.2, 0.3, 0.4 and ...
Cosmology
... What is the principal observational evidence that the age of the Universe is about 14 billion years? A. The oldest rocks (carbonaceous chondrites) in the solar system indicate an age of 14 billion years; B. Radioactive decay of heavy elements created in the Big Bang indicates an age of 14 billion y ...
... What is the principal observational evidence that the age of the Universe is about 14 billion years? A. The oldest rocks (carbonaceous chondrites) in the solar system indicate an age of 14 billion years; B. Radioactive decay of heavy elements created in the Big Bang indicates an age of 14 billion y ...
11.2 THE DOPPLER EFFECT Notes III. HOW
... Astronomers use the Doppler effect for light to calculate speeds of distant stars and galaxies. Astronomers know the chemical makeup of stars and hence their ‘true’ color. By comparing the line spectrum of light from the star with light from a laboratory source, the Doppler shift of the star's light ...
... Astronomers use the Doppler effect for light to calculate speeds of distant stars and galaxies. Astronomers know the chemical makeup of stars and hence their ‘true’ color. By comparing the line spectrum of light from the star with light from a laboratory source, the Doppler shift of the star's light ...
Redshift
In physics, redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum. In general, whether or not the radiation is within the visible spectrum, ""redder"" means an increase in wavelength – equivalent to a lower frequency and a lower photon energy, in accordance with, respectively, the wave and quantum theories of light.Some redshifts are an example of the Doppler effect, familiar in the change of apparent pitches of sirens and frequency of the sound waves emitted by speeding vehicles. A redshift occurs whenever a light source moves away from an observer. Another kind of redshift is cosmological redshift, which is due to the expansion of the universe, and sufficiently distant light sources (generally more than a few million light years away) show redshift corresponding to the rate of increase in their distance from Earth. Finally, gravitational redshift is a relativistic effect observed in electromagnetic radiation moving out of gravitational fields. Conversely, a decrease in wavelength is called blueshift and is generally seen when a light-emitting object moves toward an observer or when electromagnetic radiation moves into a gravitational field. However, redshift is a more common term and sometimes blueshift is referred to as negative redshift.Knowledge of redshifts and blueshifts has been applied to develop several terrestrial technologies such as Doppler radar and radar guns. Redshifts are also seen in the spectroscopic observations of astronomical objects. Its value is represented by the letter z.A special relativistic redshift formula (and its classical approximation) can be used to calculate the redshift of a nearby object when spacetime is flat. However, in many contexts, such as black holes and Big Bang cosmology, redshifts must be calculated using general relativity. Special relativistic, gravitational, and cosmological redshifts can be understood under the umbrella of frame transformation laws. There exist other physical processes that can lead to a shift in the frequency of electromagnetic radiation, including scattering and optical effects; however, the resulting changes are distinguishable from true redshift and are not generally referred to as such (see section on physical optics and radiative transfer).