![- SelectedWorks](http://s1.studyres.com/store/data/015645460_1-b681ea4346300def86ba0d563356259d-300x300.png)
- SelectedWorks
... nearby sister system, the Andromeda galaxy, M31. However, studying the detailed kinematics of stars in even a nearby external galaxy is quite challenging. In fact, the first problem arises from its very nearness: M31 subtends such a large angle on the sky that many spectroscopic instruments are unabl ...
... nearby sister system, the Andromeda galaxy, M31. However, studying the detailed kinematics of stars in even a nearby external galaxy is quite challenging. In fact, the first problem arises from its very nearness: M31 subtends such a large angle on the sky that many spectroscopic instruments are unabl ...
environmental effects on galaxy evolution in nearby clusters
... for comparative studies. By combining for the first time GALEX UV observations with optical, near and far infrared data, the evolutionary history of cluster galaxies is studied. The main goals of this thesis are: (a) The study of the dependence of the UV emission of galaxies from their morphological ...
... for comparative studies. By combining for the first time GALEX UV observations with optical, near and far infrared data, the evolutionary history of cluster galaxies is studied. The main goals of this thesis are: (a) The study of the dependence of the UV emission of galaxies from their morphological ...
harlow shapley - National Academy of Sciences
... dimensions and average distances and also the masses of the component stars. Russell's interest was primarily in the physics of the stars, but Shapley from the start thought in terms of exploring the depths of the universe. He saw the eclipsing binaries as potential standard candles observable to gr ...
... dimensions and average distances and also the masses of the component stars. Russell's interest was primarily in the physics of the stars, but Shapley from the start thought in terms of exploring the depths of the universe. He saw the eclipsing binaries as potential standard candles observable to gr ...
Chemical Evolution of Galactic Systems
... is whether pollution from intermediate-mass stellar winds is responsible for anomalous abundances in globular cluster stars. We test this scenario by modelling the formation and chemical evolution of a globular cluster. Recently, the most detailed abundance pattern ever measured beyond the local uni ...
... is whether pollution from intermediate-mass stellar winds is responsible for anomalous abundances in globular cluster stars. We test this scenario by modelling the formation and chemical evolution of a globular cluster. Recently, the most detailed abundance pattern ever measured beyond the local uni ...
The Ionized Nebula surrounding the Red Supergiant W26 in
... Sher 25 was ejected during the star’s current BSG phase or a previous RSG phase (e.g., Smartt et al. 2002) and the detection of similar structures around a RSG might help resolve this. While Sher 25 does have two polar outflows, one side is notably brighter than the other, which might suggest that a ...
... Sher 25 was ejected during the star’s current BSG phase or a previous RSG phase (e.g., Smartt et al. 2002) and the detection of similar structures around a RSG might help resolve this. While Sher 25 does have two polar outflows, one side is notably brighter than the other, which might suggest that a ...
a0041_Spectral Analysis and Classification of Herbig A
... Optical spectra were obtained for 75 of the 99 stars in the Herbig and Bell Catalog (HBC; Herbig & Bell 1988) having spectral types B, A, and F. Observations were made during 1999 July and 2000 January using the 1.5 m telescope of the Whipple Observatory with the FAST Spectrograph (Fabricant et al. ...
... Optical spectra were obtained for 75 of the 99 stars in the Herbig and Bell Catalog (HBC; Herbig & Bell 1988) having spectral types B, A, and F. Observations were made during 1999 July and 2000 January using the 1.5 m telescope of the Whipple Observatory with the FAST Spectrograph (Fabricant et al. ...
CHEMICAL ABUNDANCE DISTRIBUTIONS OF GALACTIC HALOS
... King model (King 1962), whose extent is set by the observed trend of core radius with luminosity for Local Group dwarfs. With all possible freedom in the model now constrained, it additionally produces the observed stellar mass–circular velocity (M-vcirc) relation for Local Group dwarfs (both the a ...
... King model (King 1962), whose extent is set by the observed trend of core radius with luminosity for Local Group dwarfs. With all possible freedom in the model now constrained, it additionally produces the observed stellar mass–circular velocity (M-vcirc) relation for Local Group dwarfs (both the a ...
The most metal-poor galaxies
... value. Thus metallicity depends on what one looks at: stars or gas, and if one considers gas – what phase: neutral atomic, molecular or ionised? Moreover the metallicity of stars is found to depend on their age, and depends on which elements are investigated. That a star or nebula is deficient of a ...
... value. Thus metallicity depends on what one looks at: stars or gas, and if one considers gas – what phase: neutral atomic, molecular or ionised? Moreover the metallicity of stars is found to depend on their age, and depends on which elements are investigated. That a star or nebula is deficient of a ...
A systematic study of X-ray variability in the ROSAT all
... variability studies of individual sources using the RASS data (Schmitt 1994), however, up to now no systematic search for variability in the total all-sky survey data has been carried out. The first great advantage of the RASS data set is that it is unbiased in the sense that no specific objects or ...
... variability studies of individual sources using the RASS data (Schmitt 1994), however, up to now no systematic search for variability in the total all-sky survey data has been carried out. The first great advantage of the RASS data set is that it is unbiased in the sense that no specific objects or ...
Asymptotic Giant Branch stars viewed up-close and far-off
... 12 C and 16 O, creating a carbon-oxygen core. When the central helium is exhausted, the star expands again and moves up the second red giant branch, the AGB. Before the first thermal pulse (see below) the star consists of an electron degenerate C/O core, surrounded by a helium-burning shell and a hy ...
... 12 C and 16 O, creating a carbon-oxygen core. When the central helium is exhausted, the star expands again and moves up the second red giant branch, the AGB. Before the first thermal pulse (see below) the star consists of an electron degenerate C/O core, surrounded by a helium-burning shell and a hy ...
CONNECTING ANGULAR MOMENTUM AND GALACTIC DYNAMICS
... in several studies over the last decades. In particular, the idea arose that angular momentum conservation should allow to infer the total angular momentum of the entire dark matter halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especi ...
... in several studies over the last decades. In particular, the idea arose that angular momentum conservation should allow to infer the total angular momentum of the entire dark matter halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especi ...
CHARACTERIZING DUST ATTENUATION IN LOCAL STAR FORMING GALAXIES: UV AND... REDDENING ABSTRACT The dust attenuation for a sample of ∼10000 local (z ....
... as the latter is required to determine the Balmer decrement. These cross-matched cases are determined using the Mikulski Archive for Space Telescopes (MAST) CasJobs website5 , with the requirement that the separation between objects be within 3′′ to be a match. Since our analysis requires detection ...
... as the latter is required to determine the Balmer decrement. These cross-matched cases are determined using the Mikulski Archive for Space Telescopes (MAST) CasJobs website5 , with the requirement that the separation between objects be within 3′′ to be a match. Since our analysis requires detection ...
Physical Properties of Wolf-Rayet Stars
... Typically, WR stars have masses of 10–25 M , and are descended from O-type stars. They spend ∼10% of their ∼5-Myr lifetime as WR stars (Meynet & Maeder 2005). At Solar metallicity the minimum initial mass for a star to become a WR star is ∼25 M . This corresponds closely to the Humphreys & Davidso ...
... Typically, WR stars have masses of 10–25 M , and are descended from O-type stars. They spend ∼10% of their ∼5-Myr lifetime as WR stars (Meynet & Maeder 2005). At Solar metallicity the minimum initial mass for a star to become a WR star is ∼25 M . This corresponds closely to the Humphreys & Davidso ...
THE UV-OPTICAL COLOR MAGNITUDE DIAGRAM. II. PHYSICAL
... physical characteristics of galaxies along this sequence are related to scaling relations typically derived for galaxies of different morphological types. We find, among other trends, that our measure of the star formation rate surface density, SFR , is nearly constant along this sequence. We discu ...
... physical characteristics of galaxies along this sequence are related to scaling relations typically derived for galaxies of different morphological types. We find, among other trends, that our measure of the star formation rate surface density, SFR , is nearly constant along this sequence. We discu ...
Universe of Motion - Reciprocal System of theory
... significance, therefore, that in application to astronomical phenomena, the theory of the universe of motion, the Reciprocal System of theory, as we are calling it, has the characteristics of a new instrument of exceptional power and versatility, rather than those of an ordinary theory. Astronomy ha ...
... significance, therefore, that in application to astronomical phenomena, the theory of the universe of motion, the Reciprocal System of theory, as we are calling it, has the characteristics of a new instrument of exceptional power and versatility, rather than those of an ordinary theory. Astronomy ha ...
Where stars form: inside-out growth and coherent star formation from
... Skelton et al. 2014). These photometric catalogs form the scaffolding of this project upon which all the remaining data products rest. For this study, we rely on the rest-frame colors, stellar masses, and star formation rates. All of these quantities were derived based on constraints from across the ...
... Skelton et al. 2014). These photometric catalogs form the scaffolding of this project upon which all the remaining data products rest. For this study, we rely on the rest-frame colors, stellar masses, and star formation rates. All of these quantities were derived based on constraints from across the ...
New Evidence for Mass-Loss from δ Cephei from H i 21
... pattern in the VLA images caused by large-scale Galactic emission diminishes near VLSR = 13.8 km s−1 . Furthermore, that same channel exhibits an extended H i emission region centered near the position of δ Cephei. Looking toward higher velocities, we find a series of 15 contiguous channels where spa ...
... pattern in the VLA images caused by large-scale Galactic emission diminishes near VLSR = 13.8 km s−1 . Furthermore, that same channel exhibits an extended H i emission region centered near the position of δ Cephei. Looking toward higher velocities, we find a series of 15 contiguous channels where spa ...
Astronomy Astrophysics
... (as in Borissova et al. 2011) and we expect minimal contamination from spurious detections. This is because the identified cluster candidates stem from a color–magnitude analysis (and 30% are confirmed by spectroscopy). Our new sample is also of particular interest since it is projected against the ...
... (as in Borissova et al. 2011) and we expect minimal contamination from spurious detections. This is because the identified cluster candidates stem from a color–magnitude analysis (and 30% are confirmed by spectroscopy). Our new sample is also of particular interest since it is projected against the ...
Abd al-Rahman al-Sufi and his book of the fixed stars: a journey of
... not claim to be an expert in all these fields and I was always grateful to receive constructive comments and corrections on the various topics, which are relevant to this study. Therefore to conduct this study I first had to understand the history of ancient classical astronomy and the main events t ...
... not claim to be an expert in all these fields and I was always grateful to receive constructive comments and corrections on the various topics, which are relevant to this study. Therefore to conduct this study I first had to understand the history of ancient classical astronomy and the main events t ...
Variability of young solar-type stars: Spot cycles, rotation
... the distribution of the starspots. Measurements of the chromospheric emission level by high resolution spectroscopy will furthermore directly provide useful estimates of the activity level of a star. Despite the fact that activity related phenomena have been studied on stars other than the Sun alrea ...
... the distribution of the starspots. Measurements of the chromospheric emission level by high resolution spectroscopy will furthermore directly provide useful estimates of the activity level of a star. Despite the fact that activity related phenomena have been studied on stars other than the Sun alrea ...
Evolutionary paths among different red galaxy types at 0.3< z< 1.5
... According to the MK -z distribution of the red galaxies sample, the faintest absolute magnitude for which the catalogue is complete in luminosity up to z ∼ 1.5 corresponds to MK,lim ∼ −24 mag. According to the redshift evolution of the mass-to-light relation (assuming a Salpeter IMF) derived by Arno ...
... According to the MK -z distribution of the red galaxies sample, the faintest absolute magnitude for which the catalogue is complete in luminosity up to z ∼ 1.5 corresponds to MK,lim ∼ −24 mag. According to the redshift evolution of the mass-to-light relation (assuming a Salpeter IMF) derived by Arno ...
Applications of Photospheric Spot Temperature Models ... Stellar Angular Momentum Evolution
... Those studies detecting a bimodal rotation period distribution find that stars with disks tend to distribute around one rotation period, while stars without disks tend to distribute around another rotation period. For those studies reporting a bimodal distribution, the favored period modes are two ...
... Those studies detecting a bimodal rotation period distribution find that stars with disks tend to distribute around one rotation period, while stars without disks tend to distribute around another rotation period. For those studies reporting a bimodal distribution, the favored period modes are two ...
AGN host galaxies at redshift z ≈ 0.7: peculiar or not?
... morphological perturbations with respect to non-AGN. Such perturbations could be signatures of gravitational interactions which are suspected as one of the triggering mechanisms of nuclear activity. Methods. Using images of non-AGN galaxies and stars we create synthetic AGN images to investigate the ...
... morphological perturbations with respect to non-AGN. Such perturbations could be signatures of gravitational interactions which are suspected as one of the triggering mechanisms of nuclear activity. Methods. Using images of non-AGN galaxies and stars we create synthetic AGN images to investigate the ...
OBSERVATIONS OF PHYSICAL PROCESSES IN
... though they are expected in a cool core with radio emission. We simulate X-ray images with various bubble configurations and sizes to set limits on what we could have missed in the data. We analyze narrow band Hα imaging and optical spectra and find elongation of the Hα filaments along the same east ...
... though they are expected in a cool core with radio emission. We simulate X-ray images with various bubble configurations and sizes to set limits on what we could have missed in the data. We analyze narrow band Hα imaging and optical spectra and find elongation of the Hα filaments along the same east ...
Cosmic distance ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are ""close enough"" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.The ladder analogy arises because no one technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.