Chandra
... emissivity scaled like density squared multiplied by a constant filling factor and used a slightly modified ,6-velocity law with ,6 = 1. They also assumed that x-ray emission only "turns on" above a certain minimum radius R min , based on line-driving models that suggest instabilities don't develop ...
... emissivity scaled like density squared multiplied by a constant filling factor and used a slightly modified ,6-velocity law with ,6 = 1. They also assumed that x-ray emission only "turns on" above a certain minimum radius R min , based on line-driving models that suggest instabilities don't develop ...
THE PRIMORDIAL HELIUM ABUNDANCE Manuel Peimbert
... theory of relativity, now known as the Big Bang Theory (BBT), predicts that during the first four minutes, counted from the beginning of the expansion of the universe, there were nuclear reactions based on hydrogen that produced helium, and traces of deuterium and lithium. During the expansion, the ...
... theory of relativity, now known as the Big Bang Theory (BBT), predicts that during the first four minutes, counted from the beginning of the expansion of the universe, there were nuclear reactions based on hydrogen that produced helium, and traces of deuterium and lithium. During the expansion, the ...
2_ISM - UCT Astronomy Department
... Why? The history review of history of determining shape and size of galaxies have shown the importance of dust absorption and scattering, and Rayleigh scattering in the determination of the true size of the Galaxy • distances to object in the Galaxy • mapping distances to other galaxies • determinat ...
... Why? The history review of history of determining shape and size of galaxies have shown the importance of dust absorption and scattering, and Rayleigh scattering in the determination of the true size of the Galaxy • distances to object in the Galaxy • mapping distances to other galaxies • determinat ...
File
... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
... * A long time ago, astronomers thought that the Earth was the centre of the Universe. This was called the geocentric model. The evidence for this model came from observations of the sky using the naked eye. After the telescope was invented, astronomers quickly gathered evidence which showed that the ...
Galaxy Evolution Encyclopedia of Astronomy & Astrophysics eaa.iop.org Mauro Giavalisco
... own Milky Way and others that have one thousandth its luminosity. Some galaxies have very regular shapes, other are amorphous. There are galaxies with spheroidal shape that have little amount of rotation, and whose stars have large ‘thermal motions’ (like the molecules of a hot fluid), and galaxies ...
... own Milky Way and others that have one thousandth its luminosity. Some galaxies have very regular shapes, other are amorphous. There are galaxies with spheroidal shape that have little amount of rotation, and whose stars have large ‘thermal motions’ (like the molecules of a hot fluid), and galaxies ...
The Formation and Evolution of Massive Black Holes - Ira-Inaf
... massive star is to collapse into a black hole with a mass similar to that of its progenitor. However, this is not the case when the content of heavy elements increases. In today’s universe, a very massive star would lose most of its mass in powerful winds before collapsing into a stellar mass black ...
... massive star is to collapse into a black hole with a mass similar to that of its progenitor. However, this is not the case when the content of heavy elements increases. In today’s universe, a very massive star would lose most of its mass in powerful winds before collapsing into a stellar mass black ...
Gravity, entropy, and cosmology: in search of clarity - Philsci
... The first issue I wish to address — and the one which bears on my “first principle” is that of gravitational entropy: namely, is it true that to allow for gravity in considering the thermodynamics of a system is to allow for the entropy of that system’s gravitational degrees of freedom? It will help ...
... The first issue I wish to address — and the one which bears on my “first principle” is that of gravitational entropy: namely, is it true that to allow for gravity in considering the thermodynamics of a system is to allow for the entropy of that system’s gravitational degrees of freedom? It will help ...
Wandering in the Redshift Desert
... helps to go into the near-infrared. Figures 8 and 9 are analogous to the previNTR SVN jFTQDR ATS 2%1 @MC M* are now plotted v. the J-band magnitude instead of the B-band. Clearly, whereas a B < 25 mag selection misses most of the SFR and most of the stellar mass at zp] @ J < 24 mag selection would p ...
... helps to go into the near-infrared. Figures 8 and 9 are analogous to the previNTR SVN jFTQDR ATS 2%1 @MC M* are now plotted v. the J-band magnitude instead of the B-band. Clearly, whereas a B < 25 mag selection misses most of the SFR and most of the stellar mass at zp] @ J < 24 mag selection would p ...
OGLE-2009-BLG-092/MOA-2009-BLG-137: A Dramatic Repeating
... Just after the perturbation, real-time analysis of the event was conducted using data available ...
... Just after the perturbation, real-time analysis of the event was conducted using data available ...
Lecture21 - Michigan State University
... atomic hydrogen is confined to an extremely flat layer that is about 400 LY thick • In the plane of the Galaxy, this cold hydrogen extends out 80,000 LY from the center • Dust is also confined to the plane of the Galaxy being about the same thickness as the hydrogen gas but more concentrated in the ...
... atomic hydrogen is confined to an extremely flat layer that is about 400 LY thick • In the plane of the Galaxy, this cold hydrogen extends out 80,000 LY from the center • Dust is also confined to the plane of the Galaxy being about the same thickness as the hydrogen gas but more concentrated in the ...
Strong linear polarization of V4332 Sagittarii: a dusty disc geometry⋆
... It is difficult to explain that high polarization with dichroic extinction caused by aligned non-spherical grains. There is no known alignment mechanism, which could give the required high alignment efficiency (e.g. Bastien & Menard 1990). The only alternative is the light scattering in circumstellar ma ...
... It is difficult to explain that high polarization with dichroic extinction caused by aligned non-spherical grains. There is no known alignment mechanism, which could give the required high alignment efficiency (e.g. Bastien & Menard 1990). The only alternative is the light scattering in circumstellar ma ...
Testing GR with ground
... observation: chirp rate depends only chirp mass h = (Asymm.) (M/R) (M/r) – The amplitude gives strain caused in space as the wave propagates – For binaries the amplitude depends only on chirpmass5/3/distance ...
... observation: chirp rate depends only chirp mass h = (Asymm.) (M/R) (M/r) – The amplitude gives strain caused in space as the wave propagates – For binaries the amplitude depends only on chirpmass5/3/distance ...
The Gaseous Halo of NGC 891 Edmund Hodges-Kluck Joel Bregman
... • Is most of the hot material outflow or inflow? • What is the connection, if any, between the hot and cool components? ...
... • Is most of the hot material outflow or inflow? • What is the connection, if any, between the hot and cool components? ...
A new view of galaxy evolution
... distant galaxies, simply because distant galax- associated with photons at wavelengths less ies are fainter than nearby galaxies, and thus it than 912 Å is enough to ionize hydrogen. Thus, is possible, perhaps even likely, that we this light is easily absorbed by the copious are missing a significan ...
... distant galaxies, simply because distant galax- associated with photons at wavelengths less ies are fainter than nearby galaxies, and thus it than 912 Å is enough to ionize hydrogen. Thus, is possible, perhaps even likely, that we this light is easily absorbed by the copious are missing a significan ...
ASPEN WORKSHOP 2003
... OII and strong Balmer absn (EW of Hdelta a few Ang) associated with center (can measure rotation curves at z=1 in good seeing)—only a 10% starburst in last few Gyrs, they were pretty well established at z=2 Fundamental Plane at z=1 is mostly consistent with z(form) of 3, except for 2 younger outlier ...
... OII and strong Balmer absn (EW of Hdelta a few Ang) associated with center (can measure rotation curves at z=1 in good seeing)—only a 10% starburst in last few Gyrs, they were pretty well established at z=2 Fundamental Plane at z=1 is mostly consistent with z(form) of 3, except for 2 younger outlier ...
Introduction to Observational Cosmology
... The basic pillars of our cosmological picture (i.e. we are starting with the answer first) 1. Averaged over sufficiently large scales, the universe is nearly homogeneous and isotropic (=cosmological principle) 2. The universe, i.e. space itself, is expanding so that the distance D between any pairs ...
... The basic pillars of our cosmological picture (i.e. we are starting with the answer first) 1. Averaged over sufficiently large scales, the universe is nearly homogeneous and isotropic (=cosmological principle) 2. The universe, i.e. space itself, is expanding so that the distance D between any pairs ...
sections 23-25 powerpoint
... Elliptical galaxy (E). A spheroidal galaxy containing millions to billions of old low-mass stars and no gas or dust. Spiral Galaxy (S). A galaxy with a spheroidal bulge of several million old low-mass stars and a flattened pancake-like disk of billions of old low-mass and young high-mass stars, alon ...
... Elliptical galaxy (E). A spheroidal galaxy containing millions to billions of old low-mass stars and no gas or dust. Spiral Galaxy (S). A galaxy with a spheroidal bulge of several million old low-mass stars and a flattened pancake-like disk of billions of old low-mass and young high-mass stars, alon ...
Lambda-CDM model
The ΛCDM (Lambda cold dark matter) or Lambda-CDM model is a parametrization of the Big Bang cosmological model in which the universe contains a cosmological constant, denoted by Lambda (Greek Λ), associated with dark energy, and cold dark matter (abbreviated CDM). It is frequently referred to as the standard model of Big Bang cosmology, because it is the simplest model that provides a reasonably good account of the following properties of the cosmos: the existence and structure of the cosmic microwave background the large-scale structure in the distribution of galaxies the abundances of hydrogen (including deuterium), helium, and lithium the accelerating expansion of the universe observed in the light from distant galaxies and supernovaeThe model assumes that general relativity is the correct theory of gravity on cosmological scales.It emerged in the late 1990s as a concordance cosmology, after a period of time when disparate observed properties of the universe appeared mutually inconsistent, and there was no consensus on the makeup of the energy density of the universe.The ΛCDM model can be extended by adding cosmological inflation, quintessence and other elements that are current areas of speculation and research in cosmology.Some alternative models challenge the assumptions of the ΛCDM model. Examples of these are modified Newtonian dynamics, modified gravity and theories of large-scale variations in the matter density of the universe.