Dark Matter: Observational Constraints Properties of Dark Matter:
... in hydrostatic equilibrium, central regions would be dense enough to be easily observed. • Molecular gas must be H2; large quantities would be ionized and observed near the galactic plane; in absorption against background quasars. If warm, would cool through quadrupole emission and be visible. ...
... in hydrostatic equilibrium, central regions would be dense enough to be easily observed. • Molecular gas must be H2; large quantities would be ionized and observed near the galactic plane; in absorption against background quasars. If warm, would cool through quadrupole emission and be visible. ...
Stellar Masses
... Hubble’s Law • The prelude to Hubble’s Law was the establishment of measurements of galactic distances and also measurements of their Doppler shifts. • Vesto Slipher [Lowell Observatory] measured the redshifts of many galaxies[nebulae] in the early decades of the 20thC. They were expected to be ran ...
... Hubble’s Law • The prelude to Hubble’s Law was the establishment of measurements of galactic distances and also measurements of their Doppler shifts. • Vesto Slipher [Lowell Observatory] measured the redshifts of many galaxies[nebulae] in the early decades of the 20thC. They were expected to be ran ...
Galaxy Zoo: Pre and post‐workshop information
... Wilson in the US. He took a photo of Andromeda (which can be seen on a clear night with the naked eye). Hubble grouped these galaxies according to similar characteristics. The Galaxy Zoo project (www.galaxyzoo.org) is an example of citizen science whereby the public have an opportunity to contribute ...
... Wilson in the US. He took a photo of Andromeda (which can be seen on a clear night with the naked eye). Hubble grouped these galaxies according to similar characteristics. The Galaxy Zoo project (www.galaxyzoo.org) is an example of citizen science whereby the public have an opportunity to contribute ...
Lecture 17: General Relativity and Black Holes
... 33. The approximate number of stars in our galaxy? _______ 24. The approximate diameter of our own galaxy? _______ 25. The galactic north pole is in what constellation? _______ 1. The Sun is located at the center of the Milky Way Galaxy. True or false 2. Shapley overestimated the dimensions of the M ...
... 33. The approximate number of stars in our galaxy? _______ 24. The approximate diameter of our own galaxy? _______ 25. The galactic north pole is in what constellation? _______ 1. The Sun is located at the center of the Milky Way Galaxy. True or false 2. Shapley overestimated the dimensions of the M ...
- ORIGINS Space Telescope
... OST will utilize the unique power of the infrared fine-structure emission lines to trace the rise of metals from the first galaxies until today. The present day Universe is rich in metals heavier than helium that enable efficient cooling of gas in the ISM in order to form stars, create planets and m ...
... OST will utilize the unique power of the infrared fine-structure emission lines to trace the rise of metals from the first galaxies until today. The present day Universe is rich in metals heavier than helium that enable efficient cooling of gas in the ISM in order to form stars, create planets and m ...
Scattering (and the blue sky)
... In other galaxies, the arms are easy to see because their ISM does not hide optical diagnostics from us. There are always only a few arms (often 2), and they are never too tightly wound. O & B stars ...
... In other galaxies, the arms are easy to see because their ISM does not hide optical diagnostics from us. There are always only a few arms (often 2), and they are never too tightly wound. O & B stars ...
The Hubble Space Telescope - the first 10 years
... from the ground. The larger panel shows the core as seen by HST. The purple and blue regions indicate where star clusters are forming ...
... from the ground. The larger panel shows the core as seen by HST. The purple and blue regions indicate where star clusters are forming ...
runaway - Astronomy & Astrophysics Group
... Milky Way. With the aid of the telescope this has been scrutinized so directly and with such ocular certainty that all the disputes which have vexed philosophers through so many ages have been resolved, and we are at last freed from wordy debates about it. The galaxy is, in fact, nothing but a colle ...
... Milky Way. With the aid of the telescope this has been scrutinized so directly and with such ocular certainty that all the disputes which have vexed philosophers through so many ages have been resolved, and we are at last freed from wordy debates about it. The galaxy is, in fact, nothing but a colle ...
May 2015 - Hermanus Astronomy
... cosmology is how such massive structures assembled in the early universe. Astronomers have found objects in the distant universe seen at a time when it was only 3 billion years old that could be precursors of the clusters seen around us today. Herschel revealed that the vast majority of Planck-detec ...
... cosmology is how such massive structures assembled in the early universe. Astronomers have found objects in the distant universe seen at a time when it was only 3 billion years old that could be precursors of the clusters seen around us today. Herschel revealed that the vast majority of Planck-detec ...
Galaxies • Test 3 (New date) – Thurs, 9 April
... there must have been gas 20 Myrs ago. (Compare to age of the sun, 4.5Byrs.) ...
... there must have been gas 20 Myrs ago. (Compare to age of the sun, 4.5Byrs.) ...
Announcements Evolution of High-Mass Stars: Red Supergiants
... The Halo has very little gas, and no new stars are forming there. The halo of the galaxy is populated by old stars. (Population II stars) ...
... The Halo has very little gas, and no new stars are forming there. The halo of the galaxy is populated by old stars. (Population II stars) ...
Introduction to Galaxies and Cosmology Exercises 2
... b) What would the period of the Earth’s revolution around the Sun be? 7. For every mass m which is swallowed by a black hole (via an accretion disk, say), an amount of energy νmc2 is liberated, where ν is the efficiency of the process. A value of ν = 0.1 is realistic. At what rate Ṁ would a superma ...
... b) What would the period of the Earth’s revolution around the Sun be? 7. For every mass m which is swallowed by a black hole (via an accretion disk, say), an amount of energy νmc2 is liberated, where ν is the efficiency of the process. A value of ν = 0.1 is realistic. At what rate Ṁ would a superma ...
Build your own Galaxy - McDonald Observatory
... Central bulge: the cotton-ball dome.The rounded structure in the central 6,400 lightyears of the galaxy’s center is what astronomers call the bulge of our galaxy. Disk: foam batting on the poster board. The disk of stars in our galaxy contains gas, dust, and stars. Generally, it is flat like the bri ...
... Central bulge: the cotton-ball dome.The rounded structure in the central 6,400 lightyears of the galaxy’s center is what astronomers call the bulge of our galaxy. Disk: foam batting on the poster board. The disk of stars in our galaxy contains gas, dust, and stars. Generally, it is flat like the bri ...
Document
... Morphology, Density & The Relationship Morphology? Galaxy types: Irregular, Spiral and elliptical galaxies and everything in between. ...
... Morphology, Density & The Relationship Morphology? Galaxy types: Irregular, Spiral and elliptical galaxies and everything in between. ...
Astronomy Review revised Key
... 23. If the star is located 4.3 light years away, how long will it be before we see the light of the star? 4.4 years. 18. What is the Big Bang Theory? The theory that all matter was once condensed into a single point called the singularity, and that singularity exploded sending matter out in all dir ...
... 23. If the star is located 4.3 light years away, how long will it be before we see the light of the star? 4.4 years. 18. What is the Big Bang Theory? The theory that all matter was once condensed into a single point called the singularity, and that singularity exploded sending matter out in all dir ...
Friday, January 27, 2017 First exam a week from today. Review
... Some suggested an alien structure. Bunk (no heat signal), but still not well explained with serious science. ...
... Some suggested an alien structure. Bunk (no heat signal), but still not well explained with serious science. ...
12/08/14-- Student ID ______ TA Name
... best telescopes in the world. What was the original goal of their research and what kind of surprise did they ...
... best telescopes in the world. What was the original goal of their research and what kind of surprise did they ...
Clusters of galaxies
... 15 IFU + 15 sky Each IFU is only 20 elements, 3x2 arcsec, 0.5 arcsec pixels. ...
... 15 IFU + 15 sky Each IFU is only 20 elements, 3x2 arcsec, 0.5 arcsec pixels. ...
Lecture 24, PPT version
... • Lookback times (universe as a time machine) • Galaxies “here and now” vs. “there and then” • Direct evidence of galaxy evolution (test of big bang theory) • Importance of collisions and mergers for establishing galaxy morphology • Active galaxies (including quasars): light from material nearby cen ...
... • Lookback times (universe as a time machine) • Galaxies “here and now” vs. “there and then” • Direct evidence of galaxy evolution (test of big bang theory) • Importance of collisions and mergers for establishing galaxy morphology • Active galaxies (including quasars): light from material nearby cen ...
Catching Andromeda`s Light
... By Ken Croswell, Ph.D. ~ Photo by Robert Gendler A galaxy is a huge collection of stars, gas, and dust that are held close to one another by gravity. The Andromeda Galaxy is the closest giant galaxy to our own. By observing Andromeda, astronomers have learned a lot about our Galaxy, the Milky Way. A ...
... By Ken Croswell, Ph.D. ~ Photo by Robert Gendler A galaxy is a huge collection of stars, gas, and dust that are held close to one another by gravity. The Andromeda Galaxy is the closest giant galaxy to our own. By observing Andromeda, astronomers have learned a lot about our Galaxy, the Milky Way. A ...
lecture25
... What is the shape of the Milky Way galaxy? How do we know where we are in the Galaxy? What wavelengths of radiation effectively penetrate the dusty interstellar medium? How do we know the rotating structure of the Galaxy? ...
... What is the shape of the Milky Way galaxy? How do we know where we are in the Galaxy? What wavelengths of radiation effectively penetrate the dusty interstellar medium? How do we know the rotating structure of the Galaxy? ...
Sample final exam
... 18. Two binary stars, each with a mass of 0.5 solar masses, orbit each other. Each has a semi-major axis of its orbit of 1.0 AU. What is the period (in years) of these stars? Essay section part one — Choose two of the following questions, and answer them in paragraph style or with drawings, as the ...
... 18. Two binary stars, each with a mass of 0.5 solar masses, orbit each other. Each has a semi-major axis of its orbit of 1.0 AU. What is the period (in years) of these stars? Essay section part one — Choose two of the following questions, and answer them in paragraph style or with drawings, as the ...
The Ionization Structure of the Irregular Galaxy NGC 4449
... ionized. H II regions characteristically include several bright, hot stars whose ultraviolet radiation is converted to visible light as described earlier. A typical H II region in our galaxy has a diameter of a few parsecs, a gas temperature of 10,000 K with a density of about 100 to 10,000 particle ...
... ionized. H II regions characteristically include several bright, hot stars whose ultraviolet radiation is converted to visible light as described earlier. A typical H II region in our galaxy has a diameter of a few parsecs, a gas temperature of 10,000 K with a density of about 100 to 10,000 particle ...
Galaxy
.jpg?width=300)
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas and dust, and dark matter. The word galaxy is derived from the Greek galaxias (γαλαξίας), literally ""milky"", a reference to the Milky Way. Galaxies range in size from dwarfs with just a few thousand (103) stars to giants with one hundred trillion (1014) stars, each orbiting their galaxy's own center of mass. Galaxies are categorized according to their visual morphology, including elliptical, spiral, and irregular. Many galaxies are thought to have black holes at their active centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than our own Sun. As of July 2015, EGSY8p7 is the oldest and most distant galaxy with a light travel distance of 13.2 billion light-years from Earth, and observed as it existed 570 million years after the Big Bang. Previously, as of May 2015, EGS-zs8-1 was the most distant known galaxy, estimated to have a light travel distance of 13.1 billion light-years away and to have 15% of the mass of the Milky Way.Approximately 170 billion (1.7 × 1011) to 200 billion (2.0 × 1011) galaxies exist in the observable universe. Most of the galaxies are 1,000 to 100,000 parsecs in diameter and usually separated by distances on the order of millions of parsecs (or megaparsecs). The space between galaxies is filled with a tenuous gas with an average density less than one atom per cubic meter. The majority of galaxies are gravitationally organized into associations known as galaxy groups, clusters, and superclusters. At the largest scale, these associations are generally arranged into sheets and filaments that are surrounded by immense voids.