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The ATLAS3D Project – XXX. Star formation histories and stellar
... The Fe5015 index lies on top of the strong [O III] emission line at 5007Å. For this index, the apparent scatter is driven by a number of galaxies sitting below the main relation. To test whether this is the result of infill from poorly subtracted [O III] emission or genuinely weaker iron, we use the ...
... The Fe5015 index lies on top of the strong [O III] emission line at 5007Å. For this index, the apparent scatter is driven by a number of galaxies sitting below the main relation. To test whether this is the result of infill from poorly subtracted [O III] emission or genuinely weaker iron, we use the ...
Michell, Laplace and the Origin of the Black Hole Concept
... Sun spin the seven planets in almost circular orbits. However, Laplace did not consider comets to be part of the Solar System as some travelled in highly eccentric orbits, and while they moved into the Sun’s domain they also moved far beyond the planetary sphere. ...
... Sun spin the seven planets in almost circular orbits. However, Laplace did not consider comets to be part of the Solar System as some travelled in highly eccentric orbits, and while they moved into the Sun’s domain they also moved far beyond the planetary sphere. ...
The formation of disc galaxies in high-resolution moving
... progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. The target galaxies themselves have been selected randomly from a sma ...
... progressively higher mass particles whose mass grows with distance from the target galaxy. This saves computational time while still ensuring the correct cosmological tidal field and mass infall rate for the forming target galaxy. The target galaxies themselves have been selected randomly from a sma ...
A UV study of nearby luminous infrared galaxies: star formation
... The advent of the GALEX ultra-violet (UV) space telescope (Martin et al. 2005) is revolutionising our understanding of the local Universe in the UV wavelengths (shortward of ∼ 3000Å). The UV spectrum is overwhelmingly dominated by flux from young massive main sequence stars, making it an ideal prob ...
... The advent of the GALEX ultra-violet (UV) space telescope (Martin et al. 2005) is revolutionising our understanding of the local Universe in the UV wavelengths (shortward of ∼ 3000Å). The UV spectrum is overwhelmingly dominated by flux from young massive main sequence stars, making it an ideal prob ...
Reconciling Dwarf Galaxies with LCDM Cosmology Andrew Wetzel F RE
... dark-matter subhalos in CDM —> Can a CDM-based model produce a satellite stellar mass function as observed? “too big to fail” problem dark-matter subhalos in CDM are too dense compared with observed satellite galaxies —> Can a CDM-based model produce a satellite dynamical mass (velocity dispersion) ...
... dark-matter subhalos in CDM —> Can a CDM-based model produce a satellite stellar mass function as observed? “too big to fail” problem dark-matter subhalos in CDM are too dense compared with observed satellite galaxies —> Can a CDM-based model produce a satellite dynamical mass (velocity dispersion) ...
GRB 021004: A Possible Shell Nebula around a Wolf
... velocity profile for one set of initial conditions. Faster outflowing absorbers can be explained by nearby circumstellar material, while more distant absorbers will evolve slower. After final velocity is achieved the absorbers simply coast along. In particular, the simulations are able to reproduce ...
... velocity profile for one set of initial conditions. Faster outflowing absorbers can be explained by nearby circumstellar material, while more distant absorbers will evolve slower. After final velocity is achieved the absorbers simply coast along. In particular, the simulations are able to reproduce ...
The Search for Directed Intelligence
... One of the enabling technologies that is relevant is the extremely dramatic progress in solid state lasers and in particular to laser amplifiers that can be arrayed into larger elements. The latter point is the analog of phased array radar that is becoming more common. An analogous revolution is tak ...
... One of the enabling technologies that is relevant is the extremely dramatic progress in solid state lasers and in particular to laser amplifiers that can be arrayed into larger elements. The latter point is the analog of phased array radar that is becoming more common. An analogous revolution is tak ...
The spectroscopic Hertzsprung-Russell diagram
... Methods. Our spectroscopic Hertzsprung-Russell (sHR) diagram shows the inverse of the flux-mean gravity versus the effective temperature. Observed stars whose spectra have been quantitatively analyzed can be entered in this diagram without the knowledge of the stellar distance or absolute brightness ...
... Methods. Our spectroscopic Hertzsprung-Russell (sHR) diagram shows the inverse of the flux-mean gravity versus the effective temperature. Observed stars whose spectra have been quantitatively analyzed can be entered in this diagram without the knowledge of the stellar distance or absolute brightness ...
Polaris B, an optical companion of Polaris (alpha UMi) system
... (i) Radial velocity values for Polaris B are close to γ =−15.9±0.06 km s−1 of Polaris A system. (ii) High projected rotational velocity v sin i = 110 km s−1 is an evidence that system is young and Polaris B is likely to be single, since most binaries of A − F types have slow rotation, the angular mo ...
... (i) Radial velocity values for Polaris B are close to γ =−15.9±0.06 km s−1 of Polaris A system. (ii) High projected rotational velocity v sin i = 110 km s−1 is an evidence that system is young and Polaris B is likely to be single, since most binaries of A − F types have slow rotation, the angular mo ...
The stellar populations in the low-luminosity, early
... which are much fainter than our original sample of LLEs, and have stellar masses of only a few × 107 M or less (
... which are much fainter than our original sample of LLEs, and have stellar masses of only a few × 107 M or less (
Stellar interactions in dense and sparse star clusters
... Context. Stellar encounters potentially affect the evolution of the protoplanetary discs in the Orion Nebula Cluster (ONC). However, the role of encounters in other cluster environments is less known. Aims. We investigate the effect of the encounter-induced disc-mass loss in different cluster environme ...
... Context. Stellar encounters potentially affect the evolution of the protoplanetary discs in the Orion Nebula Cluster (ONC). However, the role of encounters in other cluster environments is less known. Aims. We investigate the effect of the encounter-induced disc-mass loss in different cluster environme ...
A SPECTROSCOPIC STUDY OF A LARGE SAMPLE OF WOLF-RAYET GALAXIES
... hence cannot be distinguished from other WR stars in low-resolution spectra. Additionally, WNE stars are not as luminous as WNL stars in the optical range. The WR star lifetime in the WNE stage is short compared to that in the WNL stage for nearly all metallicities and progenitor star masses (Maeder ...
... hence cannot be distinguished from other WR stars in low-resolution spectra. Additionally, WNE stars are not as luminous as WNL stars in the optical range. The WR star lifetime in the WNE stage is short compared to that in the WNL stage for nearly all metallicities and progenitor star masses (Maeder ...
Teaching Tips Table of Contents - Hubble Deep Field
... The Mathematical World: C. Shapes By the end of 8th grade, students should know that ...
... The Mathematical World: C. Shapes By the end of 8th grade, students should know that ...
Science Book - Chapter 1: Introduction
... such as neutron star and black hole binaries and high-energy transients, such as optical counterparts to gamma-ray bursts and X-ray flashes (at least some of which apparently mark the deaths of massive stars). LSST will also characterize in detail active galactic nuclei (AGN) variability and new cla ...
... such as neutron star and black hole binaries and high-energy transients, such as optical counterparts to gamma-ray bursts and X-ray flashes (at least some of which apparently mark the deaths of massive stars). LSST will also characterize in detail active galactic nuclei (AGN) variability and new cla ...
Merging white dwarfs and thermonuclear supernovae
... Our alternative is that SN Ia result generally from mergers of carbon–oxygen white dwarfs, including those with sub-Chandrasekhar total mass [3]. Both theoretical [3] and empirical [24] rates are a factor 3 or so higher than near-Chandrasekhar rates, making them consistent with the SN Ia rate. Furth ...
... Our alternative is that SN Ia result generally from mergers of carbon–oxygen white dwarfs, including those with sub-Chandrasekhar total mass [3]. Both theoretical [3] and empirical [24] rates are a factor 3 or so higher than near-Chandrasekhar rates, making them consistent with the SN Ia rate. Furth ...
The Celestial Sphere CHAPTER 1
... 1.11 Using the identities, cos.90ı t/ D sin t and sin.90ı t/ D cos t, together with the small-angle approximations cos 1 and sin 1, the expression immediately reduces to sin.ı C ı/ D sin ı C cos ı cos : Using the identity sin.a C b/ D sin a cos b C cos a sin b, the expression now ...
... 1.11 Using the identities, cos.90ı t/ D sin t and sin.90ı t/ D cos t, together with the small-angle approximations cos 1 and sin 1, the expression immediately reduces to sin.ı C ı/ D sin ı C cos ı cos : Using the identity sin.a C b/ D sin a cos b C cos a sin b, the expression now ...
IAC_L3_thickdisk
... the disk, e.g. via Jeans equation. Is there more matter in the disk that we can account for from census of visible objects ? The tracer sample must be in equilibrium so the stars need to be older than a few Gyr. The last few estimates have used K dwarfs and K giants - probably OK but they do include ...
... the disk, e.g. via Jeans equation. Is there more matter in the disk that we can account for from census of visible objects ? The tracer sample must be in equilibrium so the stars need to be older than a few Gyr. The last few estimates have used K dwarfs and K giants - probably OK but they do include ...
A 25 micron search for Vega-like disks around main
... much less frequent, but they still exist. The precise mechanism that prevents these older disks from dissipating is still an open question (Jourdain de Muizon et al. 2001). The search for new Vega-like stars has been based either on the analysis of the infrared colours using the IRAS database (Fajar ...
... much less frequent, but they still exist. The precise mechanism that prevents these older disks from dissipating is still an open question (Jourdain de Muizon et al. 2001). The search for new Vega-like stars has been based either on the analysis of the infrared colours using the IRAS database (Fajar ...
MASSIVE GALAXIES IN COSMOLOGICAL SIMULATIONS: ULTRAVIOLET-SELECTED
... than R < 25:5 at z ¼ 2 is about 2 ; 102 h3 Mpc3 for E(B V ) ¼ 0:15 in our most representative run, roughly 1 order of magnitude larger than that of Lyman break galaxies at z ¼ 3. The most massive galaxies at z ¼ 2 have stellar masses of k1011 M, and their observed-frame GR colors lie in the ra ...
... than R < 25:5 at z ¼ 2 is about 2 ; 102 h3 Mpc3 for E(B V ) ¼ 0:15 in our most representative run, roughly 1 order of magnitude larger than that of Lyman break galaxies at z ¼ 3. The most massive galaxies at z ¼ 2 have stellar masses of k1011 M, and their observed-frame GR colors lie in the ra ...
Quantifying substructure in galaxy clusters
... Hubble time. In the framework of the hierarchical structure formation scenario, clusters grow mainly by mergers of smaller objects and by accretion; substructure indicates recent major mergers. Starting from these ideas and the early termination of growth of density perturbations in a low density un ...
... Hubble time. In the framework of the hierarchical structure formation scenario, clusters grow mainly by mergers of smaller objects and by accretion; substructure indicates recent major mergers. Starting from these ideas and the early termination of growth of density perturbations in a low density un ...
ASTR 610 Theory of Galaxy Formation
... Here DD(r) r is the number of pairs with separations r ± r/2 in the data, and RR(r) r is the corresponding number of pairs if point process is random. Other `estimators’ for (r) are also available in the literature, but as long as the data sample is sufficiently large, the above is more than adequat ...
... Here DD(r) r is the number of pairs with separations r ± r/2 in the data, and RR(r) r is the corresponding number of pairs if point process is random. Other `estimators’ for (r) are also available in the literature, but as long as the data sample is sufficiently large, the above is more than adequat ...
Boron Abundances Across the" Li
... rather than disappearing by nondestructive diffusion which would have brought up Li atoms from the radiative zone.) Deliyannis et al. (1998) and Boesgaard et al. (2001) have shown that Li and Be abundances are correlated in F field stars on the cool side of the Li-Be dip (Teff = 5900 - 6650 K). Boes ...
... rather than disappearing by nondestructive diffusion which would have brought up Li atoms from the radiative zone.) Deliyannis et al. (1998) and Boesgaard et al. (2001) have shown that Li and Be abundances are correlated in F field stars on the cool side of the Li-Be dip (Teff = 5900 - 6650 K). Boes ...
The Binary Populations of Eight Globular Clusters in the Outer Halo
... We exploit three indexes provided by the adopted software and described in detail by Anderson et al. (2008) as diagnostics of photometric quality: the fraction of flux in the stellar aperture from its neighbours (o), the fractional residuals in the fit of the PSF to the pixel (q), and the rms of the ...
... We exploit three indexes provided by the adopted software and described in detail by Anderson et al. (2008) as diagnostics of photometric quality: the fraction of flux in the stellar aperture from its neighbours (o), the fractional residuals in the fit of the PSF to the pixel (q), and the rms of the ...
A Detection Method for Small Kuiper Belt Objects: The Search for
... been neglected. We will show here that taking star light diffraction into account is a sine qua non condition for addressing and implementing such a detection method. We thus explore here the possibility of detecting KBOs by a method of “serendipitous occultations” by taking into account the diffrac ...
... been neglected. We will show here that taking star light diffraction into account is a sine qua non condition for addressing and implementing such a detection method. We thus explore here the possibility of detecting KBOs by a method of “serendipitous occultations” by taking into account the diffrac ...
maximum likelihood fitting of tidal streams with application
... turnoff stars in 300 deg2 of this stripe, roughly centered on the place where the Sgr stream crosses it. Unlike galaxies, the distances of stars cannot be inferred from their radial velocities. By selecting only stars with colors consistent with spheroid F turnoff stars, we select a stellar populati ...
... turnoff stars in 300 deg2 of this stripe, roughly centered on the place where the Sgr stream crosses it. Unlike galaxies, the distances of stars cannot be inferred from their radial velocities. By selecting only stars with colors consistent with spheroid F turnoff stars, we select a stellar populati ...
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.