Is there a Supermassive Black Hole at the Center of the Milky Way?
... picture of these “radio galaxies.” The radio waves did not come from the galaxy itself, but from two giant “lobes” symmetrically placed about, but well separated from, the parent galaxy (see Fig. 1). These lobes can be among the largest structures in the Universe, hundreds of times the size of the p ...
... picture of these “radio galaxies.” The radio waves did not come from the galaxy itself, but from two giant “lobes” symmetrically placed about, but well separated from, the parent galaxy (see Fig. 1). These lobes can be among the largest structures in the Universe, hundreds of times the size of the p ...
Part I: Shining a Light on Visual Magnitude
... light in all directions equally, so we can treat them as isotropic point source emitters. Their irradiance or brightness is a combination of the star's temperature, size, and distance from the observer. We can measure the visual magnitude of other objects in the sky (such as planets, galaxies, or ev ...
... light in all directions equally, so we can treat them as isotropic point source emitters. Their irradiance or brightness is a combination of the star's temperature, size, and distance from the observer. We can measure the visual magnitude of other objects in the sky (such as planets, galaxies, or ev ...
Isotopic composition of Hg and Pt in 5 slowly rotating HgMn stars *
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
My Constellation
... Õ M7 (NGC 6475) has no name, but is clearly the best deep sky object of the constellation. This magnificent open cluster is extremely large (two full-moon diameters) and quite bright, being visible even to the naked eye under the right conditions. Õ M7 is an open cluster. It's about 800 light years ...
... Õ M7 (NGC 6475) has no name, but is clearly the best deep sky object of the constellation. This magnificent open cluster is extremely large (two full-moon diameters) and quite bright, being visible even to the naked eye under the right conditions. Õ M7 is an open cluster. It's about 800 light years ...
The Physical Properties of Normal A Stars
... significant to being significant with decreasing temperature Many peculiar A stars are detected at classification dispersions (e.g., many mCP stars) while Cowley’s superficially normal A stars (e.g., the HgMn and the marginal Am stars) at higher dispersions. Other peculiar A stars are classified on ...
... significant to being significant with decreasing temperature Many peculiar A stars are detected at classification dispersions (e.g., many mCP stars) while Cowley’s superficially normal A stars (e.g., the HgMn and the marginal Am stars) at higher dispersions. Other peculiar A stars are classified on ...
3P33.pdf
... FIGURE 1. The filled squares show the UBV RIK -band data points measured around March 17.0 UT. The straight thick solid line shows a pure power law fit ( 0 32 0 12, 2 d o f 1 7), whereas the solid thin bumpy curve shows the fitted solution when a SN 1998bw-like component is added. The best SED solut ...
... FIGURE 1. The filled squares show the UBV RIK -band data points measured around March 17.0 UT. The straight thick solid line shows a pure power law fit ( 0 32 0 12, 2 d o f 1 7), whereas the solid thin bumpy curve shows the fitted solution when a SN 1998bw-like component is added. The best SED solut ...
POSTERS SESSION I: Atmospheres of Massive Stars
... Steven R. Cranmer, Harvard-Smithsonian Center for Astrophysics Massive stars have strong stellar winds that exhibit variability on timescales ranging from hours to years. Many classes of these stars are also seen, via photometric or line-profile variability, to pulsate radially or nonradially. It ha ...
... Steven R. Cranmer, Harvard-Smithsonian Center for Astrophysics Massive stars have strong stellar winds that exhibit variability on timescales ranging from hours to years. Many classes of these stars are also seen, via photometric or line-profile variability, to pulsate radially or nonradially. It ha ...
Understanding Resolution
... the inability of the eye to see fainter light at some point overwhelms the benefit of the smaller central disk. So fainter stars do have a smaller central disk diameter and may be easier to split but at some not clearly defined point are more difficult to see. Regardless of the type of scope in use, ...
... the inability of the eye to see fainter light at some point overwhelms the benefit of the smaller central disk. So fainter stars do have a smaller central disk diameter and may be easier to split but at some not clearly defined point are more difficult to see. Regardless of the type of scope in use, ...
Physics 1114OL - Normandale Community College
... Key Concepts: temperature, aperture, wavelength, frequency, speed of light, electromagnetic spectrum, ultraviolet light, infrared light, relationship between color and temperature, Doppler effect, Planck blackbody curve, continuous, absorption, and emission spectra, spectroscope, Doppler shift, chem ...
... Key Concepts: temperature, aperture, wavelength, frequency, speed of light, electromagnetic spectrum, ultraviolet light, infrared light, relationship between color and temperature, Doppler effect, Planck blackbody curve, continuous, absorption, and emission spectra, spectroscope, Doppler shift, chem ...
Lecture 15 Star Formation and Evolution 3/7
... 5 billion year old Star Cluster largest stars are gone stars little more massive the Sun have ...
... 5 billion year old Star Cluster largest stars are gone stars little more massive the Sun have ...
Fulltext PDF - Indian Academy of Sciences
... celestial equator (which determines time measurements) and the ecliptic make a considerable angle (23°26'21"). Due to these two factors, the duration of a solar day is not uniform. One therefore considers the mean solar day (madhya siivana dina) which is, loosely speaking, the average duration of a ...
... celestial equator (which determines time measurements) and the ecliptic make a considerable angle (23°26'21"). Due to these two factors, the duration of a solar day is not uniform. One therefore considers the mean solar day (madhya siivana dina) which is, loosely speaking, the average duration of a ...
4. in-flight calibration plan
... least 95% illuminated relative to an overhead sun condition their contrast is greatly enhanced. CIPS will observe scenes with and without clouds in high and low background and will track clouds into and out of the low background regions. Although most of the AIM science objectives can be accomplishe ...
... least 95% illuminated relative to an overhead sun condition their contrast is greatly enhanced. CIPS will observe scenes with and without clouds in high and low background and will track clouds into and out of the low background regions. Although most of the AIM science objectives can be accomplishe ...
Molecular Gas in Galactic Environments Abstracts (Poster)
... within ∼40 Mpc found that 22% contain CO, a common tracer for molecular gas. The presence of cold molecular gas also implies the possibility for current star formation within these galaxies. Simulations do not accurately predict the recent observations and further studies are necessary to understand ...
... within ∼40 Mpc found that 22% contain CO, a common tracer for molecular gas. The presence of cold molecular gas also implies the possibility for current star formation within these galaxies. Simulations do not accurately predict the recent observations and further studies are necessary to understand ...
P1 09 Red Shift - Animated Science
... Satellites fitted with various telescopes orbit the Earth. These telescopes detect different types of electromagnetic radiation. Why are telescopes that detect different types of electromagnetic waves used to observe the Universe? ...
... Satellites fitted with various telescopes orbit the Earth. These telescopes detect different types of electromagnetic radiation. Why are telescopes that detect different types of electromagnetic waves used to observe the Universe? ...
Comets and more
... A meteoroid is a small rocky or metallic object traveling through space Can be as small as sand or as large as 3 feet. ...
... A meteoroid is a small rocky or metallic object traveling through space Can be as small as sand or as large as 3 feet. ...
b. - UW Canvas
... Post-18.1: This graph shows the functional form of the dependence of the parallax angle on the distance an object is from Earth. If the minimum parallax angle we could measure were 0.5 arcsec, what is the maximum distance of a star that we could measure? ...
... Post-18.1: This graph shows the functional form of the dependence of the parallax angle on the distance an object is from Earth. If the minimum parallax angle we could measure were 0.5 arcsec, what is the maximum distance of a star that we could measure? ...
Observational astronomy
Observational astronomy is a division of the astronomical science that is concerned with recording data, in contrast with theoretical astrophysics, which is mainly concerned with finding out the measurable implications of physical models. It is the practice of observing celestial objects by using telescopes and other astronomical apparatus.As a science, the study of astronomy is somewhat hindered in that direct experiments with the properties of the distant universe are not possible. However, this is partly compensated by the fact that astronomers have a vast number of visible examples of stellar phenomena that can be examined. This allows for observational data to be plotted on graphs, and general trends recorded. Nearby examples of specific phenomena, such as variable stars, can then be used to infer the behavior of more distant representatives. Those distant yardsticks can then be employed to measure other phenomena in that neighborhood, including the distance to a galaxy.Galileo Galilei turned a telescope to the heavens and recorded what he saw. Since that time, observational astronomy has made steady advances with each improvement in telescope technology.A traditional division of observational astronomy is given by the region of the electromagnetic spectrum observed: Optical astronomy is the part of astronomy that uses optical components (mirrors, lenses and solid-state detectors) to observe light from near infrared to near ultraviolet wavelengths. Visible-light astronomy (using wavelengths that can be detected with the eyes, about 400 - 700 nm) falls in the middle of this range. Infrared astronomy deals with the detection and analysis of infrared radiation (this typically refers to wavelengths longer than the detection limit of silicon solid-state detectors, about 1 μm wavelength). The most common tool is the reflecting telescope but with a detector sensitive to infrared wavelengths. Space telescopes are used at certain wavelengths where the atmosphere is opaque, or to eliminate noise (thermal radiation from the atmosphere). Radio astronomy detects radiation of millimetre to dekametre wavelength. The receivers are similar to those used in radio broadcast transmission but much more sensitive. See also Radio telescopes. High-energy astronomy includes X-ray astronomy, gamma-ray astronomy, and extreme UV astronomy, as well as studies of neutrinos and cosmic rays.Optical and radio astronomy can be performed with ground-based observatories, because the atmosphere is relatively transparent at the wavelengths being detected. Observatories are usually located at high altitudes so as to minimise the absorption and distortion caused by the Earth's atmosphere. Some wavelengths of infrared light are heavily absorbed by water vapor, so many infrared observatories are located in dry places at high altitude, or in space.The atmosphere is opaque at the wavelengths used by X-ray astronomy, gamma-ray astronomy, UV astronomy and (except for a few wavelength ""windows"") far infrared astronomy, so observations must be carried out mostly from balloons or space observatories. Powerful gamma rays can, however be detected by the large air showers they produce, and the study of cosmic rays is a rapidly expanding branch of astronomy.For much of the history of observational astronomy, almost all observation was performed in the visual spectrum with optical telescopes. While the Earth's atmosphere is relatively transparent in this portion of the electromagnetic spectrum, most telescope work is still dependent on seeing conditions and air transparency, and is generally restricted to the night time. The seeing conditions depend on the turbulence and thermal variations in the air. Locations that are frequently cloudy or suffer from atmospheric turbulence limit the resolution of observations. Likewise the presence of the full Moon can brighten up the sky with scattered light, hindering observation of faint objects.For observation purposes, the optimal location for an optical telescope is undoubtedly in outer space. There the telescope can make observations without being affected by the atmosphere. However, at present it remains costly to lift telescopes into orbit. Thus the next best locations are certain mountain peaks that have a high number of cloudless days and generally possess good atmospheric conditions (with good seeing conditions). The peaks of the islands of Mauna Kea, Hawaii and La Palma possess these properties, as to a lesser extent do inland sites such as Llano de Chajnantor, Paranal, Cerro Tololo and La Silla in Chile. These observatory locations have attracted an assemblage of powerful telescopes, totalling many billion US dollars of investment.The darkness of the night sky is an important factor in optical astronomy. With the size of cities and human populated areas ever expanding, the amount of artificial light at night has also increased. These artificial lights produce a diffuse background illumination that makes observation of faint astronomical features very difficult without special filters. In a few locations such as the state of Arizona and in the United Kingdom, this has led to campaigns for the reduction of light pollution. The use of hoods around street lights not only improves the amount of light directed toward the ground, but also helps reduce the light directed toward the sky.Atmospheric effects (astronomical seeing) can severely hinder the resolution of a telescope. Without some means of correcting for the blurring effect of the shifting atmosphere, telescopes larger than about 15–20 cm in aperture can not achieve their theoretical resolution at visible wavelengths. As a result, the primary benefit of using very large telescopes has been the improved light-gathering capability, allowing very faint magnitudes to be observed. However the resolution handicap has begun to be overcome by adaptive optics, speckle imaging and interferometric imaging, as well as the use of space telescopes.Astronomers have a number of observational tools that they can use to make measurements of the heavens. For objects that are relatively close to the Sun and Earth, direct and very precise position measurements can be made against a more distant (and thereby nearly stationary) background. Early observations of this nature were used to develop very precise orbital models of the various planets, and to determine their respective masses and gravitational perturbations. Such measurements led to the discovery of the planets Uranus, Neptune, and (indirectly) Pluto. They also resulted in an erroneous assumption of a fictional planet Vulcan within the orbit of Mercury (but the explanation of the precession of Mercury's orbit by Einstein is considered one of the triumphs of his general relativity theory).