Lecture 8
... The strategy to observe a microlensing event is to monitor constantly a large number of stars to catch such a brightening when it occurs for one of them. Since the typical time scales of these events are many days, or even months, it is enough to look at each star, say, once every day or so. As most ...
... The strategy to observe a microlensing event is to monitor constantly a large number of stars to catch such a brightening when it occurs for one of them. Since the typical time scales of these events are many days, or even months, it is enough to look at each star, say, once every day or so. As most ...
Observational Evidence for Dark Matter Simona Murgia, SLAC-KIPAC XXXIX SLAC Summer Institute
... Mass density not as steeply falling as star density (exponential)! ...
... Mass density not as steeply falling as star density (exponential)! ...
Document
... Because glass has a higher index of refraction that water the convex lens at the left will still converge light, but it will converge at a greater distance from the lens that it normally would in air. This is due to the fact that the difference in index of refraction between water and glass is small ...
... Because glass has a higher index of refraction that water the convex lens at the left will still converge light, but it will converge at a greater distance from the lens that it normally would in air. This is due to the fact that the difference in index of refraction between water and glass is small ...
What constitutes the dark matter?
... fall time 1/ density, diameter sound speed fall time, mass 100.000 suns • Gibson 1996: Viscosity leads to fragmentation in gas balls of a few earth masses • If gas balls coagulate, stars form • Then Jeans cluster becomes visible as globular cluster • Most gas balls cool and freeze, their ...
... fall time 1/ density, diameter sound speed fall time, mass 100.000 suns • Gibson 1996: Viscosity leads to fragmentation in gas balls of a few earth masses • If gas balls coagulate, stars form • Then Jeans cluster becomes visible as globular cluster • Most gas balls cool and freeze, their ...
Optics
... 19. A 20 cm long pinhole camera is used to photograph the CN tower. If the actual CN tower is 553 m tall and the image is only 4.7 cm tall, how far away was the photographer from the tower? 20. A concave lens produces a virtual image of a flower petal 2.00 cm from the lens. Determine the magnificati ...
... 19. A 20 cm long pinhole camera is used to photograph the CN tower. If the actual CN tower is 553 m tall and the image is only 4.7 cm tall, how far away was the photographer from the tower? 20. A concave lens produces a virtual image of a flower petal 2.00 cm from the lens. Determine the magnificati ...
Chapter 17: Optics
... The angle of incidence at which light begins reflecting back into a refractive material is called the critical angle. The critical angle depends on the index of ...
... The angle of incidence at which light begins reflecting back into a refractive material is called the critical angle. The critical angle depends on the index of ...
Powerpoint for today
... If core with about 3 MSun or more collapses, not even neutron pressure can stop it (total mass of star about 25 MSun). Core collapses to a point, a "singularity". Gravity is so strong that nothing can escape, not even light => black hole. Schwarzschild radius for Earth is 1 cm. For a 3 MSun object, ...
... If core with about 3 MSun or more collapses, not even neutron pressure can stop it (total mass of star about 25 MSun). Core collapses to a point, a "singularity". Gravity is so strong that nothing can escape, not even light => black hole. Schwarzschild radius for Earth is 1 cm. For a 3 MSun object, ...
Chapter 23: Geometric Optics
... These are sections of spherical surfaces of radius r. We call this the radius of curvature of the mirror. If the reflecting surface is on the outside of the spherical surface we have a convex mirror (like the mirrors in stores used to monitor customers). If the reflecting surface is on the inside of ...
... These are sections of spherical surfaces of radius r. We call this the radius of curvature of the mirror. If the reflecting surface is on the outside of the spherical surface we have a convex mirror (like the mirrors in stores used to monitor customers). If the reflecting surface is on the inside of ...
REFRACTION OF LIGHT
... Snell’s law: The ratio of sine of angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media. Sin i =n, constant known as refractive idex of the medium. Sin r Refractive index give us information that how much speed of light ...
... Snell’s law: The ratio of sine of angle of incidence to the sine of angle of refraction is a constant, for the light of a given colour and for the given pair of media. Sin i =n, constant known as refractive idex of the medium. Sin r Refractive index give us information that how much speed of light ...
Chapter 14: The Milky Way Galaxy
... Given the location marked on the star's radial velocity curve, at what location in the planet's orbit (1-4) would you expect the planet to be? At 1 the planet is moving away from Earth, therefore, the star is moving toward Earth, negative radial velocity of star At 2 the planet and star are moving p ...
... Given the location marked on the star's radial velocity curve, at what location in the planet's orbit (1-4) would you expect the planet to be? At 1 the planet is moving away from Earth, therefore, the star is moving toward Earth, negative radial velocity of star At 2 the planet and star are moving p ...
Weighing a galaxy / Black holes / Quasars —16 Nov Nov-09
... There is not much light between 7 & 16 kpc. There is little light beyond 7 kpc, but the amount of mass doubles. Where there is mass there is not necessarily light from stars ...
... There is not much light between 7 & 16 kpc. There is little light beyond 7 kpc, but the amount of mass doubles. Where there is mass there is not necessarily light from stars ...
Galaxies - sciencejedi.com
... • So the galaxy has at least the mass of 100 billion suns. All told, measurements suggest that the total mass is on order of 100 trillion solar masses (1012 M⊙ ). • In 2005, it was discovered that the Milky Way does not have a spherical bulge, but rather an elongated bar structure in the core. The b ...
... • So the galaxy has at least the mass of 100 billion suns. All told, measurements suggest that the total mass is on order of 100 trillion solar masses (1012 M⊙ ). • In 2005, it was discovered that the Milky Way does not have a spherical bulge, but rather an elongated bar structure in the core. The b ...
Physics 111 Fall 2007 Reflection, Refraction and Optical Instruments
... 9. A major problem with larger diameter fibers is the difference in travel times of rays along a fiber. In traveling a distance d, the shortest time is that of the axial beam t1 = d/v, while the longest time t2 is that of a ray bouncing back and forth along the fiber just at the critical angle. Comp ...
... 9. A major problem with larger diameter fibers is the difference in travel times of rays along a fiber. In traveling a distance d, the shortest time is that of the axial beam t1 = d/v, while the longest time t2 is that of a ray bouncing back and forth along the fiber just at the critical angle. Comp ...
11-29
... A ray passing through the focal point runs parallel to the optical axis after a lens. A ray coming through a lens in parallel to the optical axis passes through the focal point. A ray running on the optical axis remains on the optical axis. A ray that pass through the geometrical center of a lens wi ...
... A ray passing through the focal point runs parallel to the optical axis after a lens. A ray coming through a lens in parallel to the optical axis passes through the focal point. A ray running on the optical axis remains on the optical axis. A ray that pass through the geometrical center of a lens wi ...
JC Beamín1,2, RA Mendez3,2, RL Smart4, R. Jara3, R
... stellar density in these fields, provides an adequate number of reference stars (above a hundred sources). These were selected among the highest S/N objects in the field of view, satisfying the condition that they appear in at least 80% of the frames, and do not exhibit large propermotions. After al ...
... stellar density in these fields, provides an adequate number of reference stars (above a hundred sources). These were selected among the highest S/N objects in the field of view, satisfying the condition that they appear in at least 80% of the frames, and do not exhibit large propermotions. After al ...
iptfsummer2014bildsten
... • Secular stability requires that the donor star stay within the Roche radius as mass is lost. • If not stable, then likely some excitement. . ...
... • Secular stability requires that the donor star stay within the Roche radius as mass is lost. • If not stable, then likely some excitement. . ...
Calcitic microlenses as part of the photoreceptor system in brittlestars
... decays as jwj w*22 , that is, it is sharply peaked in the vicinity of the optimal incident angle, with the characteristic width of the peak (w* < a0 =L0 ) being of the order of the angular resolution f. This effect suggests a plausible mechanism for targeting speci®c receptors aligned with the l ...
... decays as jwj w*22 , that is, it is sharply peaked in the vicinity of the optimal incident angle, with the characteristic width of the peak (w* < a0 =L0 ) being of the order of the angular resolution f. This effect suggests a plausible mechanism for targeting speci®c receptors aligned with the l ...
17.2 Mirrors, Lenses, and Images
... An optical system is a collection of mirrors, lenses, prisms, or other optical elements that performs a useful function with light. Characteristics of optical systems are: — The location, type, and magnification of the image. — The amount of light that is collected. — The accuracy of the image i ...
... An optical system is a collection of mirrors, lenses, prisms, or other optical elements that performs a useful function with light. Characteristics of optical systems are: — The location, type, and magnification of the image. — The amount of light that is collected. — The accuracy of the image i ...
! = ! Specular Reflection"
... • Point O and point I are on a line" perpendicular to the plane of the " mirror" ...
... • Point O and point I are on a line" perpendicular to the plane of the " mirror" ...
file - BluWiki
... o Its formula is: Basically, it is defined as the ratio of the velocity of light in free space VS. velocity of light in the material o We assumed that the index of refraction for all the different wavelengths of light in the visible spectrum was the same This allowed us to use an incandescent wh ...
... o Its formula is: Basically, it is defined as the ratio of the velocity of light in free space VS. velocity of light in the material o We assumed that the index of refraction for all the different wavelengths of light in the visible spectrum was the same This allowed us to use an incandescent wh ...
Gravitational Lensing: An Unique Probe of Dark Matter and Dark...
... Eddington and Einstein were curiously reticent about possible applications of gravitational lensing. Chwolson (1924) illustrated how lensing can produce multiple images of a distant source – a phenomenon now termed strong lensing but, as its occurrence depends on the precise alignment of a source an ...
... Eddington and Einstein were curiously reticent about possible applications of gravitational lensing. Chwolson (1924) illustrated how lensing can produce multiple images of a distant source – a phenomenon now termed strong lensing but, as its occurrence depends on the precise alignment of a source an ...
arXiv:astro-ph/9510089 v1 17 Oct 95
... these techniques holds much promise, it should be noted that different analyses of the same data sometimes lead to different conclusions. So for the time being, these estimates of β should not yet be viewed as robust [12]. In conclusion, the observational evidence for large amounts of dark matter on ...
... these techniques holds much promise, it should be noted that different analyses of the same data sometimes lead to different conclusions. So for the time being, these estimates of β should not yet be viewed as robust [12]. In conclusion, the observational evidence for large amounts of dark matter on ...
CTOpticsAns
... D) None of these Answer: A single point of light, surrounded by blackness. A point source at infinity makes a parallel bundle of rays. The lens of the eye focuses these rays onto a point on the retina, and the brain perceives a point of light. ...
... D) None of these Answer: A single point of light, surrounded by blackness. A point source at infinity makes a parallel bundle of rays. The lens of the eye focuses these rays onto a point on the retina, and the brain perceives a point of light. ...
1oo - Ryerson Mechanical Engineering Course Union (MECU)
... You have at your disposal two empty Utility Pages at the end of the examination booklet. You can use these for derivations or for rough work. If the derivation of the answer to a question is in one of these extra pages, please make sure to write a note to that effect under the question, as these pag ...
... You have at your disposal two empty Utility Pages at the end of the examination booklet. You can use these for derivations or for rough work. If the derivation of the answer to a question is in one of these extra pages, please make sure to write a note to that effect under the question, as these pag ...
How Far To The Stars? By Vanessa Soto
... D is the distance from the Earth to the object in pc. P is the parallax angle. PC is parsec, the distance to an object with a parallax angle of 1 arc second. ...
... D is the distance from the Earth to the object in pc. P is the parallax angle. PC is parsec, the distance to an object with a parallax angle of 1 arc second. ...
Gravitational microlensing
Gravitational microlensing is an astronomical phenomenon due to the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronomers can only detect bright objects that emit much light (stars) or large objects that block background light (clouds of gas and dust). These objects make up only a tiny portion of the mass of a galaxy. Microlensing allows the study of objects that emit little or no light.When a distant star or quasar gets sufficiently aligned with a massive compact foreground object, the bending of light due to its gravitational field, as discussed by Einstein in 1915, leads to two distorted unresolved images resulting in an observable magnification. The time-scale of the transient brightening depends on the mass of the foreground object as well as on the relative proper motion between the background 'source' and the foreground 'lens' object.Since microlensing observations do not rely on radiation received from the lens object, this effect therefore allows astronomers to study massive objects no matter how faint. It is thus an ideal technique to study the galactic population of such faint or dark objects as brown dwarfs, red dwarfs, planets, white dwarfs, neutron stars, black holes, andMassive Compact Halo Objects. Moreover, the microlensing effect is wavelength-independent, allowing study of source objects that emit any kind of electromagnetic radiation.Microlensing by an isolated object was first detected in 1989. Since then, microlensing has been used to constrain the nature of the dark matter, detect extrasolar planets, study limb darkening in distant stars, constrain the binary star population, and constrain the structure of the Milky Way's disk. Microlensing has also been proposed as a means to find dark objects like brown dwarfs and black holes, study starspots, measure stellar rotation, and probe quasars including their accretion disks.