possibilities for the presence of dust in polars
... density. While both model components can generate enough flux at 8 m, neither dust nor cyclotron emission alone can match the excess above the stellar components at all wavelengths. A model combining both cyclotron and dust contributions, possibly with some accretion-generated flux in the near-IR, ...
... density. While both model components can generate enough flux at 8 m, neither dust nor cyclotron emission alone can match the excess above the stellar components at all wavelengths. A model combining both cyclotron and dust contributions, possibly with some accretion-generated flux in the near-IR, ...
2 Justification and benefits in joining TMT
... Telescope (TMT). The Chinese participation in the TMT will place China in the forefront of astronomy for many decades to come; it can be a transformational experience for Chinese astronomy in terms of science, management and technology through international collaborations. The TMT partnership will f ...
... Telescope (TMT). The Chinese participation in the TMT will place China in the forefront of astronomy for many decades to come; it can be a transformational experience for Chinese astronomy in terms of science, management and technology through international collaborations. The TMT partnership will f ...
SOME CONSTRAINTS ON GALAXY EVOLUTION IMPOSED BY
... for cD, E and S0 galaxies, compared to < S > = 1.1 for all spirals. The specific frequency < S > = 9.3 in nine cD/E galaxies is higher than that in 34 E + S0 galaxies for which < S > = 5.1. Furthermore, the specific frequency < S > = 0.8 in eight late-type spirals (Sb - Scd) is significantly lower t ...
... for cD, E and S0 galaxies, compared to < S > = 1.1 for all spirals. The specific frequency < S > = 9.3 in nine cD/E galaxies is higher than that in 34 E + S0 galaxies for which < S > = 5.1. Furthermore, the specific frequency < S > = 0.8 in eight late-type spirals (Sb - Scd) is significantly lower t ...
Where stars form: inside-out growth and coherent star formation from
... 2676 galaxies enabling a division into subsamples based on stellar mass and star formation rate. By creating deep stacked Hα images, we reach surface brightness limits of 1 × 10−18 erg s−1 cm−2 arcsec−2 , allowing us to map the distribution of ionized gas out to greater than 10 kpc for typical L∗ ga ...
... 2676 galaxies enabling a division into subsamples based on stellar mass and star formation rate. By creating deep stacked Hα images, we reach surface brightness limits of 1 × 10−18 erg s−1 cm−2 arcsec−2 , allowing us to map the distribution of ionized gas out to greater than 10 kpc for typical L∗ ga ...
Modelling galaxy spectra in presence of interstellar dust – II. From
... type whose spectral energy distributions (SEDs) take into account the effect of dust in absorbing ultraviolet–optical (UV–optical) light and re-emitting it in the infrared. The models contain three main components: (i) the diffuse interstellar medium (ISM) composed of gas and dust, (ii) the large co ...
... type whose spectral energy distributions (SEDs) take into account the effect of dust in absorbing ultraviolet–optical (UV–optical) light and re-emitting it in the infrared. The models contain three main components: (i) the diffuse interstellar medium (ISM) composed of gas and dust, (ii) the large co ...
Science Case for the Chinese Participation of TMT
... Telescope (TMT). The Chinese participation in the TMT will place China in the forefront of astronomy for many decades to come; it can be a transformational experience for Chinese astronomy in terms of science, management and technology through international collaborations. The TMT partnership will f ...
... Telescope (TMT). The Chinese participation in the TMT will place China in the forefront of astronomy for many decades to come; it can be a transformational experience for Chinese astronomy in terms of science, management and technology through international collaborations. The TMT partnership will f ...
MPA Anniversary Brochure - Max Planck Institute for Astrophysics
... for the space-time waves predicted by Einstein’s theory. Nevertheless, early MPA efforts were essential for the later development of instrumentation in this field, and they were continued and greatly extended at the Max Planck Institute of Quantum Optics in Munich and at the Max Planck Institute fo ...
... for the space-time waves predicted by Einstein’s theory. Nevertheless, early MPA efforts were essential for the later development of instrumentation in this field, and they were continued and greatly extended at the Max Planck Institute of Quantum Optics in Munich and at the Max Planck Institute fo ...
From Filamentary Networks to Dense Cores in Molecular Clouds
... star clusters. Numerical simulations now successfully include turbulence, gravity, a variety of cooling processes, MHD, and most recently, radiation and radiative feedback from massive stars. These numerical advances have been essential in testing and developing new insights into the physics of fila ...
... star clusters. Numerical simulations now successfully include turbulence, gravity, a variety of cooling processes, MHD, and most recently, radiation and radiative feedback from massive stars. These numerical advances have been essential in testing and developing new insights into the physics of fila ...
DISSERTATION
... The AGB is the late evolutionary stage of stars with masses below 8 M! . These stars are characterised by a C-O degenerated core and 2 shell with ongoing nuclear reactions (He and H shells), a convective envelope and a very extended atmosphere with molecules and dust formation. As a star evolves alo ...
... The AGB is the late evolutionary stage of stars with masses below 8 M! . These stars are characterised by a C-O degenerated core and 2 shell with ongoing nuclear reactions (He and H shells), a convective envelope and a very extended atmosphere with molecules and dust formation. As a star evolves alo ...
A Detection Method for Small Kuiper Belt Objects: The Search for
... vo is maximum (≈25 km/s) toward the opposition and decreases toward a direction, called the “quadrature” hereinafter, for which ...
... vo is maximum (≈25 km/s) toward the opposition and decreases toward a direction, called the “quadrature” hereinafter, for which ...
AN ULTRA-DEEP NEAR-INFRARED SPECTRUM OF
... Several recent studies have shown that about half of the massive galaxies at z ∼ 2 are in a quiescent phase. Moreover, these galaxies are commonly found to be ultra-compact with half-light radii of ∼ 1 kpc. We have obtained a ∼ 29 hr spectrum of a typical quiescent, ultra-dense galaxy at z = 2.1865 ...
... Several recent studies have shown that about half of the massive galaxies at z ∼ 2 are in a quiescent phase. Moreover, these galaxies are commonly found to be ultra-compact with half-light radii of ∼ 1 kpc. We have obtained a ∼ 29 hr spectrum of a typical quiescent, ultra-dense galaxy at z = 2.1865 ...
Properties of White Dwarfs, Teacher Guide
... 3. When students complete their plots, guide them through answering the following questions: A. What kind of motion does Sirius show? Justify your answer. Sirius shows a periodic motion over a long time. It follows a pattern. Some background: Sirius is a nearby star – only 9 light-years away. All st ...
... 3. When students complete their plots, guide them through answering the following questions: A. What kind of motion does Sirius show? Justify your answer. Sirius shows a periodic motion over a long time. It follows a pattern. Some background: Sirius is a nearby star – only 9 light-years away. All st ...
Physical Processes in the Interstellar Medium
... bubbles filled with very hot gas (T ∼ 106 K). Although this gas would eventually cool, the temperature dependence of the atomic cooling curve at high temperatures is such that the cooling time around T ∼ 106 K is considerably longer than the cooling time in the temperature range 104 < T < 106 K (see ...
... bubbles filled with very hot gas (T ∼ 106 K). Although this gas would eventually cool, the temperature dependence of the atomic cooling curve at high temperatures is such that the cooling time around T ∼ 106 K is considerably longer than the cooling time in the temperature range 104 < T < 106 K (see ...
Structure of Hot Molecular Cores
... 2.6.4 Defining Parameters . . . . . . 2.6.5 Comparison of Model and Data 2.6.6 Searching the Parameter Space . ...
... 2.6.4 Defining Parameters . . . . . . 2.6.5 Comparison of Model and Data 2.6.6 Searching the Parameter Space . ...
SKA and VLBI synergies
... VLBI observations have remarkably strong impact in the Stellar physics studies. We can mention the study of Gamma Ray Bursts (GRBs), Radio Supernovae (RSNe) and Supernova Remnants (SNRs), Microquasars or Pulsars, among others. Moreover, VLBI astrometry is a unique tool providing stellar parallax mea ...
... VLBI observations have remarkably strong impact in the Stellar physics studies. We can mention the study of Gamma Ray Bursts (GRBs), Radio Supernovae (RSNe) and Supernova Remnants (SNRs), Microquasars or Pulsars, among others. Moreover, VLBI astrometry is a unique tool providing stellar parallax mea ...
The enigmatic pair of dwarf galaxies Leo IV and Leo V: coincidence
... previous estimates of its properties relied on a circular model and therefore also underestimated its size. With the new measurements, both galaxies have half-light major axes of over 100 pc, removing them from the ‘size gap’ that exists between dwarf galaxies and globular clusters at brighter magni ...
... previous estimates of its properties relied on a circular model and therefore also underestimated its size. With the new measurements, both galaxies have half-light major axes of over 100 pc, removing them from the ‘size gap’ that exists between dwarf galaxies and globular clusters at brighter magni ...
Celestial Object Imaging Model and Parameter Optimization for an
... The photocurrent in logarithmic response image sensors is fed to a resistor with a logarithmic current-voltage characteristic [8–10]. Logarithmic-response image sensors can obtain a wide dynamic range, but it has several disadvantages (i.e., image lag, low SNR, large fixed pattern noise, and poor im ...
... The photocurrent in logarithmic response image sensors is fed to a resistor with a logarithmic current-voltage characteristic [8–10]. Logarithmic-response image sensors can obtain a wide dynamic range, but it has several disadvantages (i.e., image lag, low SNR, large fixed pattern noise, and poor im ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.