Vacuum Ultraviolet Spectroscopy and Photochemistry of Zinc
... large excess of the host gas (deuterium or methane) onto an LiF window at 4 K. This was the minimum temperature attainable on the sample holder, with the Leybold−Heraeus flow-through liquid helium cryostat used. All of the host materials used in the present study, Ne, Ar, D2, H2, and CH4, are transpa ...
... large excess of the host gas (deuterium or methane) onto an LiF window at 4 K. This was the minimum temperature attainable on the sample holder, with the Leybold−Heraeus flow-through liquid helium cryostat used. All of the host materials used in the present study, Ne, Ar, D2, H2, and CH4, are transpa ...
Harmony of the Spheres - The William Herschel Society
... Philolaos’s ideas displeased Plato. He had presented his views on astronomy in Timeos in which he taught that the world, with its regular order, had started to exist by God’s will, an infinitely good being. The spherical form is the most perfect and all the matter in the Universe is contained in it; ...
... Philolaos’s ideas displeased Plato. He had presented his views on astronomy in Timeos in which he taught that the world, with its regular order, had started to exist by God’s will, an infinitely good being. The spherical form is the most perfect and all the matter in the Universe is contained in it; ...
Two distinct sequences of blue straggler stars in the globular cluster
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
... Creek ACT 2611, Australia Stars in globular clusters are generally believed to have all formed at the same time, early in the Galaxy's history1. 'Blue stragglers' are stars sufficiently massive2 that they should have evolved into white dwarfs long ago. Two possible mechanisms have been proposed for ...
![Chapter 4 [PDF only] - Princeton University Press](http://s1.studyres.com/store/data/016931743_1-7c8ec22374457bf50a0a03f55488ddc7-300x300.png)
Chapter 4 [PDF only] - Princeton University Press
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Horizontal branch evolutio ...
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Horizontal branch evolutio ...
Notes on Photoionized Regions 1. Introduction 2. Hydrogen Nebulae
... The existence of the helium ionization zone also modifies the hydrogen ionization zone. This is for two reasons. One is that photons above 24.6 eV are absorbed by helium and so are not availa ...
... The existence of the helium ionization zone also modifies the hydrogen ionization zone. This is for two reasons. One is that photons above 24.6 eV are absorbed by helium and so are not availa ...
STELLAR MASSES AND STAR FORMATION RATES OF LENSED DUSTY STAR-FORMING... FROM THE SPT SURVEY
... ∼100 high redshift, strongly gravitationally lensed DSFGs (Vieira et al. 2010; Mocanu et al. 2013). The lensing origin of the SPT DSFGs was confirmed by the Atacama Large Millimeter/submillimeter Array (ALMA) (Hezaveh et al. 2013; Vieira et al. 2013). The ALMA submillimeter imaging is used to model ...
... ∼100 high redshift, strongly gravitationally lensed DSFGs (Vieira et al. 2010; Mocanu et al. 2013). The lensing origin of the SPT DSFGs was confirmed by the Atacama Large Millimeter/submillimeter Array (ALMA) (Hezaveh et al. 2013; Vieira et al. 2013). The ALMA submillimeter imaging is used to model ...
Coevolution of SMBHs and host galaxies at high z
... • If the AGN fraction is larger in the protocluster simply due to the presence of more massive SMBHs, then an average protocluster AGN would be more luminous than an average field AGN by the same factor • For this to be the case, the SMBHs would have to be ≈3−10 times more massive in the protocluste ...
... • If the AGN fraction is larger in the protocluster simply due to the presence of more massive SMBHs, then an average protocluster AGN would be more luminous than an average field AGN by the same factor • For this to be the case, the SMBHs would have to be ≈3−10 times more massive in the protocluste ...
The DBV stars: Progress and problems
... essentially unchanged. Other values, such as the seismological parallax also changed; the best parallax distance is now about 45 pc, and logg = 7.95. Provencal et al. (1995) find a slightly hotter temperature of 27,000 K. Depending on the carbon mass fraction in the core, I will probably be able to ...
... essentially unchanged. Other values, such as the seismological parallax also changed; the best parallax distance is now about 45 pc, and logg = 7.95. Provencal et al. (1995) find a slightly hotter temperature of 27,000 K. Depending on the carbon mass fraction in the core, I will probably be able to ...
Electronic Text Book Unit 11
... Astronomical Do you ever wonder where our calendar comes from? Or why there is a “leap cycles year” every four years? The answers have to do with the position of Earth in space and its relationship to the sun and moon. Today we know that Earth both spins and revolves around the sun. We also know tha ...
... Astronomical Do you ever wonder where our calendar comes from? Or why there is a “leap cycles year” every four years? The answers have to do with the position of Earth in space and its relationship to the sun and moon. Today we know that Earth both spins and revolves around the sun. We also know tha ...
Folie 1
... • A cold, dense molecular cloud begins to collapse because gravity overcomes thermal pressure. • Jeans mass is the minimum or critical mass that is necessary to initiate the spontaneous collapse of the cloud. • During the initial parts of its contraction, a cloud won't heat up -- radiation escapes a ...
... • A cold, dense molecular cloud begins to collapse because gravity overcomes thermal pressure. • Jeans mass is the minimum or critical mass that is necessary to initiate the spontaneous collapse of the cloud. • During the initial parts of its contraction, a cloud won't heat up -- radiation escapes a ...
doctoral thesis (Dissertation)
... are required to explain the observed spectrum. For a electron density > 105 cm−3 all shock dimensions are so small that they remain undetectable in optical observations as observed. The spectral resolution in X-rays is not sufficient to analyse the line profiles, so UV data is used for this purpose. ...
... are required to explain the observed spectrum. For a electron density > 105 cm−3 all shock dimensions are so small that they remain undetectable in optical observations as observed. The spectral resolution in X-rays is not sufficient to analyse the line profiles, so UV data is used for this purpose. ...
Apparent Brightness, Parallax and the Distance to Sirius
... • The measured flux of light from Sirius is 1.2 X 10 – 4 ergs/ cm2 sec. From this, calculate how far away Sirius would be based on our assumption. Give your answer in cm, but then convert ...
... • The measured flux of light from Sirius is 1.2 X 10 – 4 ergs/ cm2 sec. From this, calculate how far away Sirius would be based on our assumption. Give your answer in cm, but then convert ...
Doppler Effect on Light Reflected from Revolving Mirrors:
... However, there are, at least, four available arguments, within the theoretical framework of the emissive or ballistic hypothesis, that can be advanced against the correctness of the above Majorana's conclusion: Two arguments based on the Galilean principle of relativity; one argument based on the an ...
... However, there are, at least, four available arguments, within the theoretical framework of the emissive or ballistic hypothesis, that can be advanced against the correctness of the above Majorana's conclusion: Two arguments based on the Galilean principle of relativity; one argument based on the an ...
File - Pragati fast updates
... reflection occurs when light travels from a denser medium to rarer medium. Light that is launched into an optic fiber undergoes total internal reflections at the boundary between the core and the cladding. The core has a refractive index larger than that of the cladding. Light that enters the core i ...
... reflection occurs when light travels from a denser medium to rarer medium. Light that is launched into an optic fiber undergoes total internal reflections at the boundary between the core and the cladding. The core has a refractive index larger than that of the cladding. Light that enters the core i ...
ASTR 610 Theory of Galaxy Formation
... Constructing galaxy catalogues was pioneered by Shapley and Zwicky in 1930s. A milestone was the Lick catalogue ofShane & Wirtanen (1967), which contained over 1 million galaxies identified by eye on the Lick plates, down to a limiting photographic magn. of ~18.3 ...
... Constructing galaxy catalogues was pioneered by Shapley and Zwicky in 1930s. A milestone was the Lick catalogue ofShane & Wirtanen (1967), which contained over 1 million galaxies identified by eye on the Lick plates, down to a limiting photographic magn. of ~18.3 ...
observable Universe - faculty.ucmerced.edu
... This is because (as we’ll discuss in detail later) the shortest distance between two points on a sphere (the Earth), is a curved path, a section of a great circle. Because the surface over which the line is being drawn is curved, the line itself will be curved. This can lead to some very interesting ...
... This is because (as we’ll discuss in detail later) the shortest distance between two points on a sphere (the Earth), is a curved path, a section of a great circle. Because the surface over which the line is being drawn is curved, the line itself will be curved. This can lead to some very interesting ...
Nucleosynthesis and Chemical Evolution of Oxygen
... convective core. The star will then contract until the next burning stage begins. Shell burning occurs when the region outside the formerly convective core contracts and heats to the point that the appropriate nuclear fuel can ignite. With these preliminaries in mind, we may trace the star’s evolut ...
... convective core. The star will then contract until the next burning stage begins. Shell burning occurs when the region outside the formerly convective core contracts and heats to the point that the appropriate nuclear fuel can ignite. With these preliminaries in mind, we may trace the star’s evolut ...
Michelson Interferometer
... This interferometer was originally designed by A Michelson for the accurate spectral analysis of light sources. For example, using the instrument he was able to show that the red Hα Balmer line of the hydrogen spectrum was composed of two components separated by only 0.014 nm. He was also able to me ...
... This interferometer was originally designed by A Michelson for the accurate spectral analysis of light sources. For example, using the instrument he was able to show that the red Hα Balmer line of the hydrogen spectrum was composed of two components separated by only 0.014 nm. He was also able to me ...
Estimates of relativistic electron and proton energy densities in
... The energy density of energetic protons, Up , in several nearby starburst nuclei (SBNs) has been directly deduced from γ-ray measurements of the radiative decay of π0 produced in interactions with ambient protons. Lack of sufficient sensitivity and spatial resolution makes this direct deduction unreal ...
... The energy density of energetic protons, Up , in several nearby starburst nuclei (SBNs) has been directly deduced from γ-ray measurements of the radiative decay of π0 produced in interactions with ambient protons. Lack of sufficient sensitivity and spatial resolution makes this direct deduction unreal ...
Astronomical spectroscopy
Astronomical spectroscopy is the study of astronomy using the techniques of spectroscopy to measure the spectrum of electromagnetic radiation, including visible light, which radiates from stars and other hot celestial objects. Spectroscopy can be used to derive many properties of distant stars and galaxies, such as their chemical composition, temperature, density, mass, distance, luminosity, and relative motion using Doppler shift measurements.