Dark Matter Concept Questions
... 1.54 x 1041 kg. Record your answers in the “Calculated speed” column. b) Show a sample calculation. c) Plot calculated speed against orbital radius on the graph provided. Label the line “calculated”. 3. Compare the “measured” and “calculated” plots. Discuss a possible explanation for any differences ...
... 1.54 x 1041 kg. Record your answers in the “Calculated speed” column. b) Show a sample calculation. c) Plot calculated speed against orbital radius on the graph provided. Label the line “calculated”. 3. Compare the “measured” and “calculated” plots. Discuss a possible explanation for any differences ...
Performance Factors www.cvimellesgriot.com
... The image field not only may have curvature but may also be distorted. The image of an off-axis point may be formed at a location on this surface other than that predicted by the simple paraxial equations. This distortion is different from coma (where rays from an off-axis point fail to meet perfect ...
... The image field not only may have curvature but may also be distorted. The image of an off-axis point may be formed at a location on this surface other than that predicted by the simple paraxial equations. This distortion is different from coma (where rays from an off-axis point fail to meet perfect ...
Binary Stars/Star Clusters
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
... Assumption: all stars of a given cluster formed from same Nebula ∴ All stars of a single cluster are (1) the same distance from Earth & (2) the same age ...
Deep $ I $-band imaging of $ z=\ mathsf {5.99} $ quasar
... extended X-ray source is statistically significant. It is comprised of 7 counts, which exceeds by far the expected background flux of 0.13 counts. He estimated that the probability of observing 7 photons in a 10 arcsec2 box is 5.8×10−9. What are the chances of observing a galaxy with the given magni ...
... extended X-ray source is statistically significant. It is comprised of 7 counts, which exceeds by far the expected background flux of 0.13 counts. He estimated that the probability of observing 7 photons in a 10 arcsec2 box is 5.8×10−9. What are the chances of observing a galaxy with the given magni ...
arXiv:1210.2471v1 [astro-ph.EP] 9 Oct 2012 Exoplanet Detection
... ∆θ = (1 + M∗ /Mp )∆θ∗ = (1 + M∗ /Mp ) (BX + GY )2 + (AX + F Y )2 . For circular orbits, this reduces to r⊥ = a(cos2 β + sin2 β cos2 i)1/2 , where β = ν + ωp is the angle between the position of the planet along its orbit relative to the ascending node. Planets typically orbit stars at distances from ...
... ∆θ = (1 + M∗ /Mp )∆θ∗ = (1 + M∗ /Mp ) (BX + GY )2 + (AX + F Y )2 . For circular orbits, this reduces to r⊥ = a(cos2 β + sin2 β cos2 i)1/2 , where β = ν + ωp is the angle between the position of the planet along its orbit relative to the ascending node. Planets typically orbit stars at distances from ...
Chapter26 - LSU Physics
... 26.7 Formation of Images by Lenses Like mirrors, lenses can form images of objects. But lenses are different, since the light rays actually pass thru the lens. We will again use ray tracing diagrams to determine the location, size, and orientation of images formed by lenses. In doing so, we will as ...
... 26.7 Formation of Images by Lenses Like mirrors, lenses can form images of objects. But lenses are different, since the light rays actually pass thru the lens. We will again use ray tracing diagrams to determine the location, size, and orientation of images formed by lenses. In doing so, we will as ...
matter and dark energy Gravitational lensing: a unique probe of 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 ...
Cosmic scaffolding and the growth of structure
... missions in space. Various problems encountered, but all HST-specific and none generic to space. Know what needs to be done better! Comparison of the large-scale distribution of baryons to that of mass, which could not have been done from the ground. In general, mass traces light - consistent with a ...
... missions in space. Various problems encountered, but all HST-specific and none generic to space. Know what needs to be done better! Comparison of the large-scale distribution of baryons to that of mass, which could not have been done from the ground. In general, mass traces light - consistent with a ...
unit 30: refraction and lenses
... if the incident ray hits the convex side, negative if it hits the concave side. (This sign convention may be different in other books.) The lens-maker’s formula follows directly from Snell’s law where the angles of incidence on the spherical surfaces are small so that sin θ ≈ θ. Illuminated objects ...
... if the incident ray hits the convex side, negative if it hits the concave side. (This sign convention may be different in other books.) The lens-maker’s formula follows directly from Snell’s law where the angles of incidence on the spherical surfaces are small so that sin θ ≈ θ. Illuminated objects ...
and d
... The point farthest from the eye to which an object can be placed and still be in focus is called the far point. For objects located at the far point, the ciliary muscles are completely relaxed and the lens is elongated. For young adults in their early twenties, twenties the near point is about 25 c ...
... The point farthest from the eye to which an object can be placed and still be in focus is called the far point. For objects located at the far point, the ciliary muscles are completely relaxed and the lens is elongated. For young adults in their early twenties, twenties the near point is about 25 c ...
Ray Optics and optical Instruments
... (D/fe)} where fo and fe are focal lengths of objective and eyepiece respectively. Length of the telescope (L) = (fo + ue) where, ue = distance of object from the eyepiece. (ii) When final image is formed at infinity, then M = fo/fe Length of the telescope (L) = fo + fe For large magnifying power of ...
... (D/fe)} where fo and fe are focal lengths of objective and eyepiece respectively. Length of the telescope (L) = (fo + ue) where, ue = distance of object from the eyepiece. (ii) When final image is formed at infinity, then M = fo/fe Length of the telescope (L) = fo + fe For large magnifying power of ...
VLT adaptive optics search for luminous substructures in the lens
... We are primarily interested in a clean subtraction of the lens galaxy light within the Einstein radius. To do so, we mask the area of the Einstein ring (quasars and quasar host galaxy). The use of masks ensure that Galfit does not try to fit the ring as a component of the lens galaxy. However, it ca ...
... We are primarily interested in a clean subtraction of the lens galaxy light within the Einstein radius. To do so, we mask the area of the Einstein ring (quasars and quasar host galaxy). The use of masks ensure that Galfit does not try to fit the ring as a component of the lens galaxy. However, it ca ...
Discovery of a Companion Candidate in the HD169142 Transition
... (Quanz et al. 2013b), the physical separation from the central star is 22.7±4.7 AU. This suggests that it is located within the inner cavity (see Figure 1b), right inside the inner edge of the bright rim (∼25 AU, Quanz et al. 2013b). Different scenarios can explain the L′ -band observations. Althoug ...
... (Quanz et al. 2013b), the physical separation from the central star is 22.7±4.7 AU. This suggests that it is located within the inner cavity (see Figure 1b), right inside the inner edge of the bright rim (∼25 AU, Quanz et al. 2013b). Different scenarios can explain the L′ -band observations. Althoug ...
Geometric Optics 2.0
... distance between the object and the lens (the object distance, (p)) and the distance between the lens and the image (the image distance, (i)) can be used to determine the focal length, (f) of the lens. The focal length is a measure of the imaging power of the lens. In this part of the experiment we ...
... distance between the object and the lens (the object distance, (p)) and the distance between the lens and the image (the image distance, (i)) can be used to determine the focal length, (f) of the lens. The focal length is a measure of the imaging power of the lens. In this part of the experiment we ...
Fake Source Experiment for Chandra ACIS Observations
... High spatial resolution Chandra X-ray observations have resolved many point sources in both galaxies and clusters of galaxies. The observed spatial distribution of these point sources suffer from incompleteness due to source locations, background variation, and source brightness. To investigate vari ...
... High spatial resolution Chandra X-ray observations have resolved many point sources in both galaxies and clusters of galaxies. The observed spatial distribution of these point sources suffer from incompleteness due to source locations, background variation, and source brightness. To investigate vari ...
Neutrino mass and neutrino dark matter Do non
... • Fitting with global dark matter fraction: 6 active + 6 sterile (anti-)neutrinos Mass about 1.45 eV, depends on h. Ideal case: m=1.4998 eV, h=0.744 • Gas temperature 10^8 K = alpha-particle temp., gas profile matches automatically • Baryons are poor tracers of dark matter density. • Free flow i ...
... • Fitting with global dark matter fraction: 6 active + 6 sterile (anti-)neutrinos Mass about 1.45 eV, depends on h. Ideal case: m=1.4998 eV, h=0.744 • Gas temperature 10^8 K = alpha-particle temp., gas profile matches automatically • Baryons are poor tracers of dark matter density. • Free flow i ...
The Human Eye and the colourful world
... They are also known as the defects of the eye.some common defects: Myopia, Hypermetropia,presbyopia. These are the refractive defects of vision because they are caused by the incorrect refraction of light rays by the eye-lens. Can be corrected by using suitable spherical lenses. ...
... They are also known as the defects of the eye.some common defects: Myopia, Hypermetropia,presbyopia. These are the refractive defects of vision because they are caused by the incorrect refraction of light rays by the eye-lens. Can be corrected by using suitable spherical lenses. ...
Microlensing Events by Proxima Centauri in 2014 and 2016
... To refine the impact parameters and times of closest approach, we obtained Hubble Space Telescope (HST ) images of the field on 2012 October 1. Observations were taken with the UVIS channel of the Wide Field Camera 3 (WFC3) in the F475W, F555W, F606W, and F814W filters. Since the background stars ar ...
... To refine the impact parameters and times of closest approach, we obtained Hubble Space Telescope (HST ) images of the field on 2012 October 1. Observations were taken with the UVIS channel of the Wide Field Camera 3 (WFC3) in the F475W, F555W, F606W, and F814W filters. Since the background stars ar ...
lecture25
... Light from an object incident on the first surface forms an image, which becomes the object for the second surface. A thin lens is one for which the distance from the object to each of the two surfaces is the “same” (and the distance from the image to each surface is the “same”). ...
... Light from an object incident on the first surface forms an image, which becomes the object for the second surface. A thin lens is one for which the distance from the object to each of the two surfaces is the “same” (and the distance from the image to each surface is the “same”). ...
Optics and Geometry
... Equation 4 relates the distance from the object to the image given the relative indices of refraction in the two media on both sides of the surface. Although we have not worked out all the cases, this equation is true for concave or convex lenses (where a concave lens would be indicated by a negativ ...
... Equation 4 relates the distance from the object to the image given the relative indices of refraction in the two media on both sides of the surface. Although we have not worked out all the cases, this equation is true for concave or convex lenses (where a concave lens would be indicated by a negativ ...
Working Group on Extrasolar Planets
... This is a gradualist approach with an evolving definition, guided by the observations that will decide all in the end. Emphasizing again that this is only a working definition, subject to change as we learn more about the census of low-mass companions, the WGESP has agreed to the following statement ...
... This is a gradualist approach with an evolving definition, guided by the observations that will decide all in the end. Emphasizing again that this is only a working definition, subject to change as we learn more about the census of low-mass companions, the WGESP has agreed to the following statement ...
A105 Stars and Galaxies
... – Einstein rings, arcs, and multiple images The Einstein Cross • Weak lensing - distortions are much smaller – Detected by analyzing large numbers of objects to find distortions of only a few percent. – The lensing shows up statistically as a preferred stretching of the background objects perpendicu ...
... – Einstein rings, arcs, and multiple images The Einstein Cross • Weak lensing - distortions are much smaller – Detected by analyzing large numbers of objects to find distortions of only a few percent. – The lensing shows up statistically as a preferred stretching of the background objects perpendicu ...
7 Optics
... i. When a convex lens is placed over a cross and moved from side to side, the cross that is seen moves with the direction of movement ii. When a concave lens is placed over a cross and moved from side to side, the cross that is seen moves with the direction of movement iii. When a toric lens is plac ...
... i. When a convex lens is placed over a cross and moved from side to side, the cross that is seen moves with the direction of movement ii. When a concave lens is placed over a cross and moved from side to side, the cross that is seen moves with the direction of movement iii. When a toric lens is plac ...
Microlensing Events by Proxima Centauri in 2014 and 2016
... radii of nearby stars, coupled with their typically large proper motions, yield relatively large probabilities of such events occurring. Searches for upcoming close stellar passages of high-proper-motion stars near background sources have been carried out by Salim & Gould (2000) and Proft, Demleitne ...
... radii of nearby stars, coupled with their typically large proper motions, yield relatively large probabilities of such events occurring. Searches for upcoming close stellar passages of high-proper-motion stars near background sources have been carried out by Salim & Gould (2000) and Proft, Demleitne ...
Neutrino hot dark matter and hydrodynamics of structure formation
... • Extreme Scattering Events: Earth-Jovian gas clouds observed in radio. Walker&Wardle 98: May be good fraction of galactic mass • Multiple imaging of pulsars: by MBDs in Jeans clusters • Explanation of H-alpha forest absorption lines ...
... • Extreme Scattering Events: Earth-Jovian gas clouds observed in radio. Walker&Wardle 98: May be good fraction of galactic mass • Multiple imaging of pulsars: by MBDs in Jeans clusters • Explanation of H-alpha forest absorption lines ...
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.