The Astronomers of Nabta Playa
... Wendorf’s team because a complex structure of megaliths had been placed there. One large stone stood squarely at the central point, surrounded by others. Numerous other stone complexes had also been placed in the vicinity. These appeared to be burial mounds and when the archaeologists excavated two ...
... Wendorf’s team because a complex structure of megaliths had been placed there. One large stone stood squarely at the central point, surrounded by others. Numerous other stone complexes had also been placed in the vicinity. These appeared to be burial mounds and when the archaeologists excavated two ...
Observational evidence for AGN feedback in early
... and assemble the last, contrary to what has been deduced from observations. For a critical example, these models struggle to match the observed chemical abundance ratios and their trends with galaxy mass (Thomas 1999; Nagashima et al. 2005). The reason for this failure in the early models is that SF ...
... and assemble the last, contrary to what has been deduced from observations. For a critical example, these models struggle to match the observed chemical abundance ratios and their trends with galaxy mass (Thomas 1999; Nagashima et al. 2005). The reason for this failure in the early models is that SF ...
Stellar Populations of Dwarf Elliptical Galaxies: UBVRI Photometry
... giant elliptical galaxies in the Virgo Cluster. These observations confirm the marked difference in stellar population and stellar distribution between dwarf and giant elliptical galaxies and further substantiate the need for alternative evolutionary scenarios for the lowest mass cluster galaxies. W ...
... giant elliptical galaxies in the Virgo Cluster. These observations confirm the marked difference in stellar population and stellar distribution between dwarf and giant elliptical galaxies and further substantiate the need for alternative evolutionary scenarios for the lowest mass cluster galaxies. W ...
OXYGEN IN THE SOLAR SYSTEM
... Galactic evolution refers to increases in the abundances of the secondary nuclides 18O and 17O as a consequence of increasing stellar metallicity with time compared with the linear growth rate of the primary nuclide 16O (Timmes et al. 1995). Oxygen-16 is the most abundant product of primary galactic ...
... Galactic evolution refers to increases in the abundances of the secondary nuclides 18O and 17O as a consequence of increasing stellar metallicity with time compared with the linear growth rate of the primary nuclide 16O (Timmes et al. 1995). Oxygen-16 is the most abundant product of primary galactic ...
The Relation between Interstellar Turbulence and Star Formation
... dynamical theory of star formation, and the standard theory of magnetostatic support from both observational and theoretical perspectives. We then present the outline of a new paradigm of star formation based on the interplay between supersonic turbulence and self-gravity. Supersonic turbulence can ...
... dynamical theory of star formation, and the standard theory of magnetostatic support from both observational and theoretical perspectives. We then present the outline of a new paradigm of star formation based on the interplay between supersonic turbulence and self-gravity. Supersonic turbulence can ...
From Filamentary Networks to Dense Cores in Molecular Clouds
... of lower column density material. For the purpose of this review, we will define a “filament” as any elongated ISM structure with an aspect ratio larger than ∼ 5–10 that is significantly overdense with respect to its surroundings. The results of Galactic imaging surveys carried out with the Herschel ...
... of lower column density material. For the purpose of this review, we will define a “filament” as any elongated ISM structure with an aspect ratio larger than ∼ 5–10 that is significantly overdense with respect to its surroundings. The results of Galactic imaging surveys carried out with the Herschel ...
Reassessing the formation of the inner Oort cloud
... either a Hernquist or Plummer potential – and chose other parameters based on the latest observations of embedded clusters from the literature. These other parameters result in the stars being on radial orbits and the cluster collapses. Similar to previous studies, in our simulations the inner Oort ...
... either a Hernquist or Plummer potential – and chose other parameters based on the latest observations of embedded clusters from the literature. These other parameters result in the stars being on radial orbits and the cluster collapses. Similar to previous studies, in our simulations the inner Oort ...
Red supergiants around the obscured open cluster Stephenson 2
... other RSG clusters is unclear. Though all the clusters are located at a similar distance and have similar ages, they span ∼500 pc in projection. There have been suggestions that this Scutum Complex represents a giant star formation region triggered by the dynamical excitation of the Galactic Bar, wh ...
... other RSG clusters is unclear. Though all the clusters are located at a similar distance and have similar ages, they span ∼500 pc in projection. There have been suggestions that this Scutum Complex represents a giant star formation region triggered by the dynamical excitation of the Galactic Bar, wh ...
Submm Observations of Massive Star Formation in the Giant
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
... Context. How massive stars (M>8 M ) form and how they accrete gas is still an open research field, but it is known that their influence on the interstellar medium (ISM) is immense. Star formation involves the gravitational collapse of gas from scales of giant molecular clouds (GMCs) down to dense h ...
Galactic Nebulae
... Spiral arms of Milky Way : Location of Galactic Nebulae Orion Arm – location of sun – Orion nebula- Hyades- Pleiades ...
... Spiral arms of Milky Way : Location of Galactic Nebulae Orion Arm – location of sun – Orion nebula- Hyades- Pleiades ...
Compact High-Redshift Galaxies Are the Cores of the Most Massive
... stellar mass profiles using e.g. color or stellar population gradients and comparison of profiles from different instruments and wavebands in these samples are discussed extensively in Hopkins et al. (2009a, 2008a); the differences are much smaller than the scatter between individual profiles, and d ...
... stellar mass profiles using e.g. color or stellar population gradients and comparison of profiles from different instruments and wavebands in these samples are discussed extensively in Hopkins et al. (2009a, 2008a); the differences are much smaller than the scatter between individual profiles, and d ...
Gamma Ray Burst Afterglows and Host Galaxies
... Deaths of Massive Stars Afterglow data suggests that GRBs occur… • in galaxies with active star formation, • often in regions with a lot of gas, which is where new stars form and where the most massive stars spend their entire brief lives. However, GRBs are so rare that only a tiny fraction of massi ...
... Deaths of Massive Stars Afterglow data suggests that GRBs occur… • in galaxies with active star formation, • often in regions with a lot of gas, which is where new stars form and where the most massive stars spend their entire brief lives. However, GRBs are so rare that only a tiny fraction of massi ...
Cepheids
... any color: W(BV), W(VK) etc. • W incorporates intrinsic color (and Period – Color relation) • The advantage of using the Wesenheit index W instead of the absolute magnitude M is that – (a) Wesenheit index is almost free of any ...
... any color: W(BV), W(VK) etc. • W incorporates intrinsic color (and Period – Color relation) • The advantage of using the Wesenheit index W instead of the absolute magnitude M is that – (a) Wesenheit index is almost free of any ...
First Results from the WISE Enhanced Resolution Galaxy Atlas
... plexity and sustainability of converting gas into stars. Comprising the local universe, nearby galaxies represent a fossil record of galaxy evolution, the boundary condition for cosmological models that explain past and current state of the universe. Although galaxies come in all shapes, sizes, mass ...
... plexity and sustainability of converting gas into stars. Comprising the local universe, nearby galaxies represent a fossil record of galaxy evolution, the boundary condition for cosmological models that explain past and current state of the universe. Although galaxies come in all shapes, sizes, mass ...
Chapter 5 The Evolutionary Paths Of Nearby Galaxies
... To investigate whether the quenching is due to AGN feedback or environmental effects, I divide the sample according to nuclear activity and Hi content (Figure 5.1, top row, central and right panel, respectively), as described in Chapter 2. For M∗ & 1010 M⊙ , AGN-host spirals are uniformly distribute ...
... To investigate whether the quenching is due to AGN feedback or environmental effects, I divide the sample according to nuclear activity and Hi content (Figure 5.1, top row, central and right panel, respectively), as described in Chapter 2. For M∗ & 1010 M⊙ , AGN-host spirals are uniformly distribute ...
Dark Matter, Dark Energy, and the Fate of the Universe
... Dark Matter in the Milky Way In Chapter 15, we saw how the Sun’s motion around the galaxy reveals the total amount of mass within its orbit. We can similarly use the orbital motion of any other star around the galaxy to measure the mass of the Milky Way within that star’s orbit. In principle, we co ...
... Dark Matter in the Milky Way In Chapter 15, we saw how the Sun’s motion around the galaxy reveals the total amount of mass within its orbit. We can similarly use the orbital motion of any other star around the galaxy to measure the mass of the Milky Way within that star’s orbit. In principle, we co ...
9 The Clearing of Protoplanetary Disks and of the Protosolar Nebula
... a few to 10 Myr to form Jupiter-like planets at 5 AU (see, e.g. Lissauer & Stevenson 2007), meaning that primordial gas should persist for as long in the disk. Whether terrestrial planets can form and whether their orbits will be circular as those of Earth and Venus strongly depend on the amount of ...
... a few to 10 Myr to form Jupiter-like planets at 5 AU (see, e.g. Lissauer & Stevenson 2007), meaning that primordial gas should persist for as long in the disk. Whether terrestrial planets can form and whether their orbits will be circular as those of Earth and Venus strongly depend on the amount of ...
Evidence of suppression of star formation by quasar
... tribution of galaxy colors. If AGN feedback couples to the gas as efficiently as required by galaxy formation models, then massive, early-type galaxies will be gas-poor and passively aging, while younger galaxies, typically lower-mass, late-type galaxies will still have enough star formation materia ...
... tribution of galaxy colors. If AGN feedback couples to the gas as efficiently as required by galaxy formation models, then massive, early-type galaxies will be gas-poor and passively aging, while younger galaxies, typically lower-mass, late-type galaxies will still have enough star formation materia ...
spatially resolved spitzer irs spectroscopy of the central region of m82
... Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths (EWs) of key diagnostic features, such as the [Ne ii] 12.8 m, [Ne iii] 15.5 m, and H2 S(1) 17.03 m lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH ) emission features in six representative re ...
... Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths (EWs) of key diagnostic features, such as the [Ne ii] 12.8 m, [Ne iii] 15.5 m, and H2 S(1) 17.03 m lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH ) emission features in six representative re ...
Star Formation in the Rosette Complex
... ship for a total of 30 cluster sources and to extend the list of known PMS candidates to 21. They subsequently identified members coincident with ROSAT point source catalogs and compared their properties to the rest of the sample. Six of the PMS candidates were confirmed as X-ray sources. In Figure ...
... ship for a total of 30 cluster sources and to extend the list of known PMS candidates to 21. They subsequently identified members coincident with ROSAT point source catalogs and compared their properties to the rest of the sample. Six of the PMS candidates were confirmed as X-ray sources. In Figure ...
evolución química de la nube grande de magallanes.
... (Fig. 3.7). We find that H11 lies in the range of the dSph trend and below the Galactic one. This result confirms previous studies and opens the possibility that galaxies like the LMC, assumed to be building blocks of our galaxy, may not in fact satisfy the chemical requirements, even at the low met ...
... (Fig. 3.7). We find that H11 lies in the range of the dSph trend and below the Galactic one. This result confirms previous studies and opens the possibility that galaxies like the LMC, assumed to be building blocks of our galaxy, may not in fact satisfy the chemical requirements, even at the low met ...
A New Science Strategy for Space Astronomy and Astrophysics
... In 1991 the National Research Council issued a detailed strategy for astronomy and astrophysics for the next decade,1 prepared by a committee under the leadership of John Bahcall. Like previous decadal studies in this field, the report identified in priority order the most important scientific progr ...
... In 1991 the National Research Council issued a detailed strategy for astronomy and astrophysics for the next decade,1 prepared by a committee under the leadership of John Bahcall. Like previous decadal studies in this field, the report identified in priority order the most important scientific progr ...
Chemical gradients in the Milky Way from the RAVE data
... Methods. We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by ...
... Methods. We analysed three different samples selected from three independent datasets: a sample of 19 962 dwarf stars selected from the RAVE database, a sample of 10 616 dwarf stars selected from the Geneva-Copenhagen Survey (GCS) dataset, and a mock sample (equivalent to the RAVE sample) created by ...
Thesis
... It remains a quest for modern astronomy to answer what main mechanisms set the star formation rate (SFR) of galaxies. Massive galaxies present a good starting point for such a quest due to their relatively easy detection at every redshift. Since stars form out of cold and dense gas, a comprehensive ...
... It remains a quest for modern astronomy to answer what main mechanisms set the star formation rate (SFR) of galaxies. Massive galaxies present a good starting point for such a quest due to their relatively easy detection at every redshift. Since stars form out of cold and dense gas, a comprehensive ...
The Galactic Environment of the Sun
... significant impact on a planet’s atmosphere? No one knows. These questions take on special significance in light of the fact that the interstellar medium—the sun’s galactic environment—is not a homogeneous substrate. Astronomers have discovered that interstellar material is organized into clouds of ...
... significant impact on a planet’s atmosphere? No one knows. These questions take on special significance in light of the fact that the interstellar medium—the sun’s galactic environment—is not a homogeneous substrate. Astronomers have discovered that interstellar material is organized into clouds of ...