Astronomy 21 – Test 2 – Answers
... emission (explain the astrophysical mechanism)? You have to look through dust so you have to use longer wavelength observations. The 21cm line is useful for that (it is radiation emitted during the spin flip of the electron of atomic hydrogen). Redshifts of that line can be measured and velocities c ...
... emission (explain the astrophysical mechanism)? You have to look through dust so you have to use longer wavelength observations. The 21cm line is useful for that (it is radiation emitted during the spin flip of the electron of atomic hydrogen). Redshifts of that line can be measured and velocities c ...
The future of gamma-ray astronomy
... especially at lower energies where the Fermi-LAT point spread function (PSF) exceeds several degrees. The best ways to • Potential to cover both aspects in a single mission improve the PSF are to decrease the density of the material in the tracker and to space the tracking element further apart [62 ...
... especially at lower energies where the Fermi-LAT point spread function (PSF) exceeds several degrees. The best ways to • Potential to cover both aspects in a single mission improve the PSF are to decrease the density of the material in the tracker and to space the tracking element further apart [62 ...
High-Energy Astrophysics with Gamma
... SNRs are TeV sources! (Even using Whipple criterion – accepting observations by CANGAROO on G347.3-0.5) ...
... SNRs are TeV sources! (Even using Whipple criterion – accepting observations by CANGAROO on G347.3-0.5) ...
Neutron Stars and Black Holes
... The mass of the proton is 1.67 X 10-24 g, and its radius is about 0.877 X 10-13 cm (according to the Wikipedia). The volume of the proton is 4/3 π r3 = 2.82 X 10-39 cm3. The density = mass/volume = 5.9 X 1014 g/cm3. The Sun’s mass is 2 X 1030 kg = 2 X 1033 g. A one solar mass black hole has radius r ...
... The mass of the proton is 1.67 X 10-24 g, and its radius is about 0.877 X 10-13 cm (according to the Wikipedia). The volume of the proton is 4/3 π r3 = 2.82 X 10-39 cm3. The density = mass/volume = 5.9 X 1014 g/cm3. The Sun’s mass is 2 X 1030 kg = 2 X 1033 g. A one solar mass black hole has radius r ...
Measuring the distance to Galaxies
... variables can be determined by parallax (a method you will learn in this course) The inverse square law and the periodluminosity relationship of Henrietta Leavitt enables the distance of all observable Cepheid variables to be determined ...
... variables can be determined by parallax (a method you will learn in this course) The inverse square law and the periodluminosity relationship of Henrietta Leavitt enables the distance of all observable Cepheid variables to be determined ...
The Intergalactic Medium - ISS
... source age Either the large-scale region surrounding this galaxy must have been largely reionized by z=10, with a neutral H I fraction < 0.4 Or the stars within the galaxy must be massive > 100 MSun , and capable of producing a sufficient large H II region around it ...
... source age Either the large-scale region surrounding this galaxy must have been largely reionized by z=10, with a neutral H I fraction < 0.4 Or the stars within the galaxy must be massive > 100 MSun , and capable of producing a sufficient large H II region around it ...
Document
... • Stars closer to the galactic center orbit faster • Stars farther out orbit more slowly ...
... • Stars closer to the galactic center orbit faster • Stars farther out orbit more slowly ...
Lec11_2D
... According to Kepler’s laws, matter close to a star will orbit faster than material further away. If there’s a lot of material in a disk, this will cause the atoms will rub up against each other. There will be friction! So The material will lose orbital energy and spiral in The disk will get real ...
... According to Kepler’s laws, matter close to a star will orbit faster than material further away. If there’s a lot of material in a disk, this will cause the atoms will rub up against each other. There will be friction! So The material will lose orbital energy and spiral in The disk will get real ...
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 ...
Lab 9
... Lab 9: Galaxies and the Hubble Law Objective: To demonstrate the classification of galaxies and to use a rational expression to figure out the distances to galaxies using redshift. The large-scale structure of the universe is governed by gravity. The Sun orbits the center of our galaxy, the Milky Wa ...
... Lab 9: Galaxies and the Hubble Law Objective: To demonstrate the classification of galaxies and to use a rational expression to figure out the distances to galaxies using redshift. The large-scale structure of the universe is governed by gravity. The Sun orbits the center of our galaxy, the Milky Wa ...
100 million years after the Big Bang
... Origin of bulges • Classical bulges • Formed at high redshift • Mergers/accretion/rapid collapse of overdensity ...
... Origin of bulges • Classical bulges • Formed at high redshift • Mergers/accretion/rapid collapse of overdensity ...
Summary: Nuclear burning in stars
... those farther from center. • Î automatic stretching of any feature into a trailing spiral. • But arms should rapidly wind up and disappear ...
... those farther from center. • Î automatic stretching of any feature into a trailing spiral. • But arms should rapidly wind up and disappear ...
Document
... Stars above ~1.4 times the mass of the sun have so much gravity that it overcomes the electron pressure and the star collapses to where only the neutrons are holding it up. This is a neutron star. ...
... Stars above ~1.4 times the mass of the sun have so much gravity that it overcomes the electron pressure and the star collapses to where only the neutrons are holding it up. This is a neutron star. ...
GCSE P1 1.5.4 Red shift
... after exploding suddenly in a Big Bang from a very small initial point, some 13.5 billion years ago. ...
... after exploding suddenly in a Big Bang from a very small initial point, some 13.5 billion years ago. ...
EXPLORING SPECIAL RELATIVITY USING HIGH ENERGY
... simple QG and D-brane model predictions of a retardation of photon velocity proportional to E/MQG because they would require MQG > MPlanck. More indirect results from g-ray birefringence limits, the non-decay of 50 TeV grays from the Crab Nebula, and the TeV spectra of nearby AGNs place severe limi ...
... simple QG and D-brane model predictions of a retardation of photon velocity proportional to E/MQG because they would require MQG > MPlanck. More indirect results from g-ray birefringence limits, the non-decay of 50 TeV grays from the Crab Nebula, and the TeV spectra of nearby AGNs place severe limi ...
Neutron stars and black holes
... The mass of the proton is 1.67 X 10-24 g, and its radius is about 0.877 X 10-13 cm (according to the Wikipedia). The volume of the proton is 4/3 r3 = 2.82 X 10-39 cm3. The density = mass/volume = 5.9 X 1014 g/cm3. The Sun’s mass is 2 X 1030 kg = 2 X 1033 g. A one solar mass black hole has radius r ...
... The mass of the proton is 1.67 X 10-24 g, and its radius is about 0.877 X 10-13 cm (according to the Wikipedia). The volume of the proton is 4/3 r3 = 2.82 X 10-39 cm3. The density = mass/volume = 5.9 X 1014 g/cm3. The Sun’s mass is 2 X 1030 kg = 2 X 1033 g. A one solar mass black hole has radius r ...
Galaxies – Island universes
... • If a small galaxy has a central collision with a larger spiral galaxy, the gravitational pulse can compress gas/dust and make a star formation burst in a ring. • Collision energy added to the central bulge can stretch it out into a very non-spherica ...
... • If a small galaxy has a central collision with a larger spiral galaxy, the gravitational pulse can compress gas/dust and make a star formation burst in a ring. • Collision energy added to the central bulge can stretch it out into a very non-spherica ...
Astronomy (stars, galaxies and the Universe)
... enormous explosion of concentrated matter and energy As it expanded, the Universe cooled Atoms formed after a few hundred million years The first stars and galaxies formed after about 200 million years ...
... enormous explosion of concentrated matter and energy As it expanded, the Universe cooled Atoms formed after a few hundred million years The first stars and galaxies formed after about 200 million years ...
Class 28 (Jun 2) - Physics at Oregon State University
... • We can calculate the mass of the Milky Way by measuring the orbital velocities of dwarf galaxies in orbit around our galaxy. • We can also count the number of stars in the galaxy, and estimate the galactic mass. The two numbers do not agree. By a factor of 10! • Rotation curves do not show the exp ...
... • We can calculate the mass of the Milky Way by measuring the orbital velocities of dwarf galaxies in orbit around our galaxy. • We can also count the number of stars in the galaxy, and estimate the galactic mass. The two numbers do not agree. By a factor of 10! • Rotation curves do not show the exp ...
Stars and galaxies Intro
... to focus X-rays and produce an image • The first X-ray telescopes were used to observe the sun. FYI: The Chandra X-ray Observatory ...
... to focus X-rays and produce an image • The first X-ray telescopes were used to observe the sun. FYI: The Chandra X-ray Observatory ...
Chapter 9 / Adobe Acrobat Document
... 1. A spiral galaxy is roundish but flat with a bulge in the centre. It has major and minor spiral arms that come from the centre. An elliptical galaxy is oval or cigar shaped with no visible arm structure. An irregular galaxy does not have a regular shape. 2. Galaxies form when gravity causes a larg ...
... 1. A spiral galaxy is roundish but flat with a bulge in the centre. It has major and minor spiral arms that come from the centre. An elliptical galaxy is oval or cigar shaped with no visible arm structure. An irregular galaxy does not have a regular shape. 2. Galaxies form when gravity causes a larg ...
Slide 1
... •Ellipticals have much less cool, atomic gas than spiral galaxies •< 108 – 109 Msun while an Sc galaxy contains ~1010Msun •sometimes (though rare) seen as dust lanes orbiting E’s - from merger or capture? •Ellipticals have hot, ionized gas •stars lose mass through shedding of stellar envelopes as th ...
... •Ellipticals have much less cool, atomic gas than spiral galaxies •< 108 – 109 Msun while an Sc galaxy contains ~1010Msun •sometimes (though rare) seen as dust lanes orbiting E’s - from merger or capture? •Ellipticals have hot, ionized gas •stars lose mass through shedding of stellar envelopes as th ...
Galaxy clusters - University of Iowa Astrophysics
... source, we can figure out the total mass in the lens. This provides an independent confirmation of dark matter. • A lense can act as a huge telescope. The deepest images of the most distant galaxies are obtained with clusters acting as gravitational lenses. ...
... source, we can figure out the total mass in the lens. This provides an independent confirmation of dark matter. • A lense can act as a huge telescope. The deepest images of the most distant galaxies are obtained with clusters acting as gravitational lenses. ...
IS AN ALTERNATE COSMOLOGY BECOMING NECESSARY?
... gravity in certain regions of galaxies, and a stripped down math is used to model them. Advanced math that includes more items of reality indicates black holes are not possible. Cool stars would show excess gravity in regions where they exist in vast numbers, and show effects similar to what black h ...
... gravity in certain regions of galaxies, and a stripped down math is used to model them. Advanced math that includes more items of reality indicates black holes are not possible. Cool stars would show excess gravity in regions where they exist in vast numbers, and show effects similar to what black h ...
Neutron stars, pulsars
... Pulsar Glitches A glitch is a discontinuous change of period. Short timescales - pulsar slow-down rate is remarkably uniform Longer timescales - irregularities apparent, in particular, ‘glitches’ ∆P ~ 10 −10 for Crab pulsar P ...
... Pulsar Glitches A glitch is a discontinuous change of period. Short timescales - pulsar slow-down rate is remarkably uniform Longer timescales - irregularities apparent, in particular, ‘glitches’ ∆P ~ 10 −10 for Crab pulsar P ...
Gamma-ray burst
Gamma-ray bursts (GRBs) are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the brightest electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several hours. The initial burst is usually followed by a longer-lived ""afterglow"" emitted at longer wavelengths (X-ray, ultraviolet, optical, infrared, microwave and radio).Most observed GRBs are believed to consist of a narrow beam of intense radiation released during a supernova or hypernova as a rapidly rotating, high-mass star collapses to form a neutron star, quark star, or black hole. A subclass of GRBs (the ""short"" bursts) appear to originate from a different process – this may be due to the merger of binary neutron stars. The cause of the precursor burst observed in some of these short events may be due to the development of a resonance between the crust and core of such stars as a result of the massive tidal forces experienced in the seconds leading up to their collision, causing the entire crust of the star to shatter.The sources of most GRBs are billions of light years away from Earth, implying that the explosions are both extremely energetic (a typical burst releases as much energy in a few seconds as the Sun will in its entire 10-billion-year lifetime) and extremely rare (a few per galaxy per million years). All observed GRBs have originated from outside the Milky Way galaxy, although a related class of phenomena, soft gamma repeater flares, are associated with magnetars within the Milky Way. It has been hypothesized that a gamma-ray burst in the Milky Way, pointing directly towards the Earth, could cause a mass extinction event.GRBs were first detected in 1967 by the Vela satellites, a series of satellites designed to detect covert nuclear weapons tests. Hundreds of theoretical models were proposed to explain these bursts in the years following their discovery, such as collisions between comets and neutron stars. Little information was available to verify these models until the 1997 detection of the first X-ray and optical afterglows and direct measurement of their redshifts using optical spectroscopy, and thus their distances and energy outputs. These discoveries, and subsequent studies of the galaxies and supernovae associated with the bursts, clarified the distance and luminosity of GRBs. These facts definitively placed them in distant galaxies and also connected long GRBs with the explosion of massive stars, the only possible source for the energy outputs observed.