Stellar Physics
... brighter star has its objective lens partially covered for example using an iris. This is adjusted until both stars appear equally bright when viewed through the telescopes. The ratio of the uncovered areas of the two lenses is proportional to the relative brightness of the two stars. (See Fig 1. 1) ...
... brighter star has its objective lens partially covered for example using an iris. This is adjusted until both stars appear equally bright when viewed through the telescopes. The ratio of the uncovered areas of the two lenses is proportional to the relative brightness of the two stars. (See Fig 1. 1) ...
normal and active - FirstLight Astro
... search for globsters in distant galaxies, then estimate distance ...
... search for globsters in distant galaxies, then estimate distance ...
VISIBLE STARS AS APPARENT OBSERVATIONAL EVIDENCE IN
... Jupiter's diameter exactly, it barely comes to 40 seconds, so that the sun's diameter becomes 50 times greater; but Jupiter's diameter is no less than ten times larger than that of an average fixed star (as a good telescope will show us), so that the sun's diameter is five hundred times that of an a ...
... Jupiter's diameter exactly, it barely comes to 40 seconds, so that the sun's diameter becomes 50 times greater; but Jupiter's diameter is no less than ten times larger than that of an average fixed star (as a good telescope will show us), so that the sun's diameter is five hundred times that of an a ...
PH607lec12
... Though many astronomers agree that hierarchical formation seems to be occurring, there are still some wrinkles to the theory. For example, the very most massive galaxies don't seem to be growing at as high a rate as middle-mass galaxies. When astronomers look at the brightest galaxies now compared t ...
... Though many astronomers agree that hierarchical formation seems to be occurring, there are still some wrinkles to the theory. For example, the very most massive galaxies don't seem to be growing at as high a rate as middle-mass galaxies. When astronomers look at the brightest galaxies now compared t ...
Project 1. CCD image analysis
... 4. Study of the signal to noise The signal‐to‐noise ratio (S/N) is a technical term used to characterize the quality of the signal detection of a measuring system (e.g. a CCD camera). If the measuring system is a CCD camera, then the S/N is given by the ratio of the light signal to t ...
... 4. Study of the signal to noise The signal‐to‐noise ratio (S/N) is a technical term used to characterize the quality of the signal detection of a measuring system (e.g. a CCD camera). If the measuring system is a CCD camera, then the S/N is given by the ratio of the light signal to t ...
PHY 375 - DePaul University
... The strategy in this derivation is to invert the situation. That is, instead of considering a ray of light (hence a point) moving along and striking a star surface of radius R⋆ , think instead of the light as a circular surface of radius R⋆ and the star as a point. In other words, the light moves al ...
... The strategy in this derivation is to invert the situation. That is, instead of considering a ray of light (hence a point) moving along and striking a star surface of radius R⋆ , think instead of the light as a circular surface of radius R⋆ and the star as a point. In other words, the light moves al ...
Hertzsprung–Russell diagram - Wikipedia, the free encyclopedia
... difficult; it is known to be a function of stellar composition and can be affected by other factors like stellar rotation. When converting luminosity or absolute bolometric magnitude to apparent or absolute visual magnitude, one requires a bolometric correction, which may or may not come from the sa ...
... difficult; it is known to be a function of stellar composition and can be affected by other factors like stellar rotation. When converting luminosity or absolute bolometric magnitude to apparent or absolute visual magnitude, one requires a bolometric correction, which may or may not come from the sa ...
81 KB - CSIRO Publishing
... discovered ultra-faint dwarf spheroidal (dSph) galaxies which contain very few stars, has motivated us to ask the question ‘What is a galaxy?’ Our aim here is to promote further discussion of how to define a galaxy and, in particular, what separates it from a star cluster. Like most previous definit ...
... discovered ultra-faint dwarf spheroidal (dSph) galaxies which contain very few stars, has motivated us to ask the question ‘What is a galaxy?’ Our aim here is to promote further discussion of how to define a galaxy and, in particular, what separates it from a star cluster. Like most previous definit ...
Searching for RR Lyrae Stars in M15
... an object is how luminous an object is as seen from Earth while the absolute magnitude of an object is what the apparent magnitude would be if the source was located 10 parsecs away from us. The distance modulus helps in determining distances and magnitudes to various objects. This very convenient f ...
... an object is how luminous an object is as seen from Earth while the absolute magnitude of an object is what the apparent magnitude would be if the source was located 10 parsecs away from us. The distance modulus helps in determining distances and magnitudes to various objects. This very convenient f ...
Gone in a flash: supernovae in the survey era
... past five years (for a review, see Gal-Yam 2012), SNe Ia. bers. But with very large imagers on reaching absolute magnitudes of –23 (50 times To date there are three identified classes 4 m-class facilities (e.g. Megacam on the brighter than a Type Ia supernova). The first of SLSN (Gal-Yam 2012), comm ...
... past five years (for a review, see Gal-Yam 2012), SNe Ia. bers. But with very large imagers on reaching absolute magnitudes of –23 (50 times To date there are three identified classes 4 m-class facilities (e.g. Megacam on the brighter than a Type Ia supernova). The first of SLSN (Gal-Yam 2012), comm ...
Here - Amateur Observers` Society of New York
... viewed from the earth. A lunar eclipse occurs when, on passing between the sun and the moon, the earth is closely enough aligned to hide at least some of the moon. For both solar and lunar eclipses, use the predictions listed in The Beginner’s Observing Guide and The Observer's Handbook to plan your ...
... viewed from the earth. A lunar eclipse occurs when, on passing between the sun and the moon, the earth is closely enough aligned to hide at least some of the moon. For both solar and lunar eclipses, use the predictions listed in The Beginner’s Observing Guide and The Observer's Handbook to plan your ...
Practical cosmology with the Local Volume galaxies
... i.e. obtain the known Schmidt-Kennicutt law (Kennicutt, 1998), but for the galaxies themselves, not for individual HII regions only. Therefore, evolutionary history of disks of galaxies looks to be driven mainly by internal SF processes. It is generally accepted that the enhanced star formation in g ...
... i.e. obtain the known Schmidt-Kennicutt law (Kennicutt, 1998), but for the galaxies themselves, not for individual HII regions only. Therefore, evolutionary history of disks of galaxies looks to be driven mainly by internal SF processes. It is generally accepted that the enhanced star formation in g ...
stellar spectra instructor notes
... populated only in the ground state, the lowest electronic energy level. A simple approximation is therefore u(T) = g1. In any event, there are tables that can be consulted to establish u(T) for a particular situation. ...
... populated only in the ground state, the lowest electronic energy level. A simple approximation is therefore u(T) = g1. In any event, there are tables that can be consulted to establish u(T) for a particular situation. ...
Galaxies
... • Origin, early history, and fate of the Universe • Does the Universe have a beginning? An end? What physics processes “caused” the Universe to be what it is? Are other universes possible? Would they look like ours (have the ...
... • Origin, early history, and fate of the Universe • Does the Universe have a beginning? An end? What physics processes “caused” the Universe to be what it is? Are other universes possible? Would they look like ours (have the ...
Document
... Why not to use them to search for new sources? How? Just using the fact that all known magnetars show periodicity in a narrow range! Muno et al. used 506 Chandra and 441 XMM-Newton observations of the 1033 for erg/s Galactic plane (|b|<5oL=3 ) to look sources with 5 s < P < 20 s. ...
... Why not to use them to search for new sources? How? Just using the fact that all known magnetars show periodicity in a narrow range! Muno et al. used 506 Chandra and 441 XMM-Newton observations of the 1033 for erg/s Galactic plane (|b|<5oL=3 ) to look sources with 5 s < P < 20 s. ...
PEGASUS, THE FLYING HORSE Pegasus is a constellation in the
... M15 (NGC 7078) is a globular cluster of magnitude 6.4, 34,000 light-years from Earth. It is a Shapley class IV cluster, which means that it is fairly rich and concentrated towards its Pegasus with the foal Equuleus next to it, as depicted in Urania's Mirror, a set of constellation cards published in ...
... M15 (NGC 7078) is a globular cluster of magnitude 6.4, 34,000 light-years from Earth. It is a Shapley class IV cluster, which means that it is fairly rich and concentrated towards its Pegasus with the foal Equuleus next to it, as depicted in Urania's Mirror, a set of constellation cards published in ...
THREE INTRIGUER NEBULAE IN CONSTELLATION CARINA
... Astronomical Twilight. The first step was to identify constellation Antlia whose stars, although faint, were clearly visible to the naked eye. Once the constellation was identified I focused on the region where the cluster lies. To make this possible it is necessary to fix our view on the eastern pa ...
... Astronomical Twilight. The first step was to identify constellation Antlia whose stars, although faint, were clearly visible to the naked eye. Once the constellation was identified I focused on the region where the cluster lies. To make this possible it is necessary to fix our view on the eastern pa ...
Galaxies
... Dark Matter in the Universe Galaxy mass measurements show that galaxies need between 3 and 10 times more mass than can be observed to explain their rotation curves. The discrepancy is even larger in galaxy clusters, which need 10 to 100 times more mass. The total needed is more than the sum of the ...
... Dark Matter in the Universe Galaxy mass measurements show that galaxies need between 3 and 10 times more mass than can be observed to explain their rotation curves. The discrepancy is even larger in galaxy clusters, which need 10 to 100 times more mass. The total needed is more than the sum of the ...
AGN surveys to study galaxy evolution along cosmic times
... non-blazar AGN located at |b|>5 deg, where the surveys identification completeness is ∼93%, which were used for calculating the AGN luminosity function and X-ray absorption distribution. Malizia et al. (2012) have studied the fraction of Compton-thick sources in an INTEGRAL complete AGN sample. Assum ...
... non-blazar AGN located at |b|>5 deg, where the surveys identification completeness is ∼93%, which were used for calculating the AGN luminosity function and X-ray absorption distribution. Malizia et al. (2012) have studied the fraction of Compton-thick sources in an INTEGRAL complete AGN sample. Assum ...
Local Horizon View
... Declination Local Time of Day Every star, cluster, nebula, galaxy, radio source, and quasar has a position in the night sky. All the Solar System objects - the Sun, the Moon, the other planets, asteroids, and comets have ...
... Declination Local Time of Day Every star, cluster, nebula, galaxy, radio source, and quasar has a position in the night sky. All the Solar System objects - the Sun, the Moon, the other planets, asteroids, and comets have ...
STC-Scripting Guide for Celestia
... “What is a spectral class and what does it tell about a star and its properties?”. It might be useful for beginners, but if you already know what types of stars you want to create, you can skip them. Stars are obviously emitting light, otherwise we wouldn’t be able to see them, but they do not only ...
... “What is a spectral class and what does it tell about a star and its properties?”. It might be useful for beginners, but if you already know what types of stars you want to create, you can skip them. Stars are obviously emitting light, otherwise we wouldn’t be able to see them, but they do not only ...
15-3 Notes: Galaxies
... Astronomers classify a galaxy as a spiral, elliptical, or irregular galaxy according to its shape. Spiral galaxies, such as the Andromeda galaxy, have a bulge at the center and spiral arms. The spiral arms are made up of gas, dust, and new stars that have formed. The galaxy in which we live is a spi ...
... Astronomers classify a galaxy as a spiral, elliptical, or irregular galaxy according to its shape. Spiral galaxies, such as the Andromeda galaxy, have a bulge at the center and spiral arms. The spiral arms are made up of gas, dust, and new stars that have formed. The galaxy in which we live is a spi ...
Twitter Feed ITSO Symposium 2017
... process? Spectroscopy of sources during reionisation can provide insights into this period, by setting constraints on the evolution of the neutral gas fraction with redshift, and on the topology of hydrogen reionisation. As they are extremely faint and their spectra are highly redshifted to near-inf ...
... process? Spectroscopy of sources during reionisation can provide insights into this period, by setting constraints on the evolution of the neutral gas fraction with redshift, and on the topology of hydrogen reionisation. As they are extremely faint and their spectra are highly redshifted to near-inf ...
Document
... like this: • Cool and luminous stars: large radii. • Hot and faint stars: small radii. • Most stars are here, and there is not a large variation in radius. Image from Nick Strobel’s Astronomy Notes (http://www.astronomynotes.com) ...
... like this: • Cool and luminous stars: large radii. • Hot and faint stars: small radii. • Most stars are here, and there is not a large variation in radius. Image from Nick Strobel’s Astronomy Notes (http://www.astronomynotes.com) ...
Quasars
... • This name was given because this type of object was first identified as a source of radio waves. • The name is retained today, even though astronomers now know most quasars are faint radio emitters. • Quasars also are called quasi-stellar objects (QSOs). • Due to their great distance from Earth, n ...
... • This name was given because this type of object was first identified as a source of radio waves. • The name is retained today, even though astronomers now know most quasars are faint radio emitters. • Quasars also are called quasi-stellar objects (QSOs). • Due to their great distance from Earth, n ...
Malmquist bias
The Malmquist bias is an effect in observational astronomy which leads to the preferential detection of intrinsically bright objects. It was first described in 1922 by Swedish astronomer Gunnar Malmquist (1893–1982), who then greatly elaborated upon this work in 1925. In statistics, this bias is referred to as a selection bias and affects the survey results in a brightness limited survey, where stars below a certain apparent brightness are not included. Since observed stars and galaxies appear dimmer when farther away, the brightness that is measured will fall off with distance until their brightness falls below the observational threshold. Objects which are more luminous, or intrinsically brighter, can be observed at a greater distance, creating a false trend of increasing intrinsic brightness, and other related quantities, with distance. This effect has led to many spurious claims in the field of astronomy. Properly correcting for these effects has become an area of great focus.