Formation and Evolution of Binary Millisecond Pulsars with Helium
... binary system is inherently five dimensional. The vector of parameter space contains the following elements: (i) the initial mass of the donor (M2,o ); (ii) the initial mass of the accretor (M1,o ); (iii) the initial chemical profile of the interior of the donor star (which can be correlated with it ...
... binary system is inherently five dimensional. The vector of parameter space contains the following elements: (i) the initial mass of the donor (M2,o ); (ii) the initial mass of the accretor (M1,o ); (iii) the initial chemical profile of the interior of the donor star (which can be correlated with it ...
The chemical case for no winds in dwarf irregular galaxies
... protogalaxy masses between 107 and 5 × 109 M (actual values are quoted in Table 1). For each value, different models have been run with collapse times equal to 8, 20, 40 and 60 Gyr, eliminating the link between this parameter and the total mass of the galaxy existing in Mollá & Dı́az (2005) models ...
... protogalaxy masses between 107 and 5 × 109 M (actual values are quoted in Table 1). For each value, different models have been run with collapse times equal to 8, 20, 40 and 60 Gyr, eliminating the link between this parameter and the total mass of the galaxy existing in Mollá & Dı́az (2005) models ...
Powerpoint Presentation (large file)
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
Galaxies Chapter Twenty
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
Document
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
... spiral, and irregular galaxies along with ellipticals • Giant elliptical galaxies are often found near the centers of rich clusters ...
near-infrared adaptive optics imaging of high-redshift
... the local background with respect to the overall zero level of the sky-subtracted images, we computed the average signal in a circular annulus centered on the source and with radii of about 300 Y400 and 500 Y600 . We checked that in such annular regions the average radial brightness profile of the o ...
... the local background with respect to the overall zero level of the sky-subtracted images, we computed the average signal in a circular annulus centered on the source and with radii of about 300 Y400 and 500 Y600 . We checked that in such annular regions the average radial brightness profile of the o ...
MULTI-FREQUENCY TIME VARIABILITY OF ACTIVE GALACTIC NUCLEI RITABAN CHATTERJEE
... In an active galactic nucleus (AGN), the central region of a galaxy is brighter than the rest of the galaxy and sometimes ∼10,000 times as bright as an average galaxy. The extremely high luminosities of AGNs are thought to be produced by the accretion of matter onto a supermassive black hole (1 mill ...
... In an active galactic nucleus (AGN), the central region of a galaxy is brighter than the rest of the galaxy and sometimes ∼10,000 times as bright as an average galaxy. The extremely high luminosities of AGNs are thought to be produced by the accretion of matter onto a supermassive black hole (1 mill ...
Superbubble Activity in Star-Forming Galaxies M. S. Oey
... resemble shells. Note that many SN-driven shells will not exhibit expansion velocities if they have become pressure-confined by the ambient medium, thus a lack of observed expansion velocities cannot distinguish between the feedback model and other models. It has been suggested that some of the larg ...
... resemble shells. Note that many SN-driven shells will not exhibit expansion velocities if they have become pressure-confined by the ambient medium, thus a lack of observed expansion velocities cannot distinguish between the feedback model and other models. It has been suggested that some of the larg ...
Astronomy Astrophysics Massive open star clusters using the VVV survey &
... the VVV-SkZ pipeline, and near-infrared K-band spectroscopy, following the methodology presented in the first article of the series. Results. Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster ...
... the VVV-SkZ pipeline, and near-infrared K-band spectroscopy, following the methodology presented in the first article of the series. Results. Individual distances for two observed stars indicate that the cluster is located at the far edge of the Galactic bar. These stars, which are probable cluster ...
Observations with Herschel: High-mass star formation and the
... efficient at temperatures above 10 million K and is presently producing the energy of our sun. Synthesis of even heavier elements (up to iron) takes place at much higher temperatures. For instance the triple-alpha process, in which carbon is produced, requires temperatures above 100 million degrees Ke ...
... efficient at temperatures above 10 million K and is presently producing the energy of our sun. Synthesis of even heavier elements (up to iron) takes place at much higher temperatures. For instance the triple-alpha process, in which carbon is produced, requires temperatures above 100 million degrees Ke ...
Article PDF - IOPscience
... (∼1.4–2.0 Gyr), 0.5 dex more metal-rich, and spatially more concentrated population. These young stars are also offset by 64⫹40 ⫺20 pc to the east of the galaxy center. The data suggest that this young population, which represents ∼3%–5% of the stellar mass of the galaxy within its half-light radius ...
... (∼1.4–2.0 Gyr), 0.5 dex more metal-rich, and spatially more concentrated population. These young stars are also offset by 64⫹40 ⫺20 pc to the east of the galaxy center. The data suggest that this young population, which represents ∼3%–5% of the stellar mass of the galaxy within its half-light radius ...
New Scientist - Quark Nova Project
... slower. As it spins down, the centrifugal forces that kept gravity at bay start weakening, allowing gravity to squish the star still further. In what is a blink of an eye in cosmic time, the neutrons can be converted to strange quark matter, which is a soup of up, down and strange quarks. In theory, ...
... slower. As it spins down, the centrifugal forces that kept gravity at bay start weakening, allowing gravity to squish the star still further. In what is a blink of an eye in cosmic time, the neutrons can be converted to strange quark matter, which is a soup of up, down and strange quarks. In theory, ...
Antlia, the Machine Pneumatique
... beautiful magnitude 4.2 star signals the elongated soft beam of light in a northportals to the many galaxies situated main- east to south-west direction. Furthermore, ly to the south within the constellation. it has an uneven surface brightness with a faint, barely seen nucleus. A short arcNearly tw ...
... beautiful magnitude 4.2 star signals the elongated soft beam of light in a northportals to the many galaxies situated main- east to south-west direction. Furthermore, ly to the south within the constellation. it has an uneven surface brightness with a faint, barely seen nucleus. A short arcNearly tw ...
LATE STAGES OF CLOSE BINARY SYSTEMS 1. Introduction The X
... The subsequent evolution of the system, now consisting of a helium star and an unevolved main-sequence star, depends on the mass of the helium star. Two cases are possible: (i) If the helium star has a mass below 1 AM® (the Chandrasekhar limit) it can, without difficulty, finish as a white dwarf. A1 ...
... The subsequent evolution of the system, now consisting of a helium star and an unevolved main-sequence star, depends on the mass of the helium star. Two cases are possible: (i) If the helium star has a mass below 1 AM® (the Chandrasekhar limit) it can, without difficulty, finish as a white dwarf. A1 ...
Stars and Galaxies
... Optical Telescopes There are two basic types of optical telescopes. One type uses only lenses to study light and the other uses lenses and mirrors. Optical telescopes collect visible light and produce magnified images of objects. Light is collected by an objective lens or mirror. Because starlight i ...
... Optical Telescopes There are two basic types of optical telescopes. One type uses only lenses to study light and the other uses lenses and mirrors. Optical telescopes collect visible light and produce magnified images of objects. Light is collected by an objective lens or mirror. Because starlight i ...
Teil 2
... with magnetic fields as well as for the evolution of close binaries. Due to their small physical dimensions, the orbital separations are typically less than the solar radius, they cannot resolved directly. With the help of indirect imaging techniques, however, spatial resolutions in the microarcseco ...
... with magnetic fields as well as for the evolution of close binaries. Due to their small physical dimensions, the orbital separations are typically less than the solar radius, they cannot resolved directly. With the help of indirect imaging techniques, however, spatial resolutions in the microarcseco ...
ppt
... feeding: binary companion star growth: accretor results from stellar evolution for AGN feeding: galaxy mergers? growth: accretion on to `seed’ black hole? Both problems better understood for binaries, so develop ideas and theory here first. ...
... feeding: binary companion star growth: accretor results from stellar evolution for AGN feeding: galaxy mergers? growth: accretion on to `seed’ black hole? Both problems better understood for binaries, so develop ideas and theory here first. ...
Dai, S - PulsarAstronomy.net
... Neutron Stars through Astrometric Microlensing Sahu, K. C.; Albrow, M.; Anderson, J.; Bond, H. E.; Bond, I.; Brown, T. M.; Casertano, S.; Dominik, M.; Ferguson, H. C.; Fryer, C.; Livio, M.; Mao, S.; Perrott, Y.; Udalski, A.; Yock, P. 2012, American Astronomical Society Meeting Abstracts, 220, #307.0 ...
... Neutron Stars through Astrometric Microlensing Sahu, K. C.; Albrow, M.; Anderson, J.; Bond, H. E.; Bond, I.; Brown, T. M.; Casertano, S.; Dominik, M.; Ferguson, H. C.; Fryer, C.; Livio, M.; Mao, S.; Perrott, Y.; Udalski, A.; Yock, P. 2012, American Astronomical Society Meeting Abstracts, 220, #307.0 ...
Dust and Molecules in Early Galaxies
... Spherical SF region with radius rSF surrounded by dust Radiation field strength is calculated from LOB and rSF LOB evolves according to the SF history. Based on the SFR and dust size spectrum, the total SED is constructed by a superposition of the radiation from each ...
... Spherical SF region with radius rSF surrounded by dust Radiation field strength is calculated from LOB and rSF LOB evolves according to the SF history. Based on the SFR and dust size spectrum, the total SED is constructed by a superposition of the radiation from each ...
THE LUYINOSITY VARIABILITY OF SOLAR
... relatively more vigorous magnetic activity. Thus, the existence of a causal relation between rotation and the magnetic activity of lower main-sequence stars is widely accepted. In practice, the rotation-activity relation is indirectly expressed in terms of chromospheric or coronal emission rather th ...
... relatively more vigorous magnetic activity. Thus, the existence of a causal relation between rotation and the magnetic activity of lower main-sequence stars is widely accepted. In practice, the rotation-activity relation is indirectly expressed in terms of chromospheric or coronal emission rather th ...
Demonstration of multilayer reflective optics at photon energies
... code (MCNP6 [24]) at each energy. At 0.51 MeV the incoherent scattering contribution is less than 1% of the detected counts while it increases to 2.5% at 0.65 MeV. Two reflectivity models are shown in Figure 3. The idealized model describes the location and shape of the reflectance peaks at both ene ...
... code (MCNP6 [24]) at each energy. At 0.51 MeV the incoherent scattering contribution is less than 1% of the detected counts while it increases to 2.5% at 0.65 MeV. Two reflectivity models are shown in Figure 3. The idealized model describes the location and shape of the reflectance peaks at both ene ...
PS1-12SK IS A PECULIAR SUPERNOVA FROM A HE
... transient with properties that indicate atypical star formation in its host galaxy cluster or pose a challenge to popular progenitor system models for this class of explosion. The optical spectra of PS112sk classify it as a Type Ibn SN (c.f. SN 2006jc), dominated by intermediate-width (3 × 103 km s− ...
... transient with properties that indicate atypical star formation in its host galaxy cluster or pose a challenge to popular progenitor system models for this class of explosion. The optical spectra of PS112sk classify it as a Type Ibn SN (c.f. SN 2006jc), dominated by intermediate-width (3 × 103 km s− ...
A detached white dwarf/M dwarf binary with an
... We find that the white dwarf GD 448 is a detached white dwarf/M dwarf binary with an orbital period of 2.47 h. This is the shortest period known for such a binary, placing it in the centre of the 'period gap' from 2 to 3 h in which few cataclysmic variable stars (mass-transferring white dwarf/main-s ...
... We find that the white dwarf GD 448 is a detached white dwarf/M dwarf binary with an orbital period of 2.47 h. This is the shortest period known for such a binary, placing it in the centre of the 'period gap' from 2 to 3 h in which few cataclysmic variable stars (mass-transferring white dwarf/main-s ...
A variation of the fraction of stars that form in
... cluster in our catalogue, we used radial bins with limits of R[pc] = (372, 2153, 2700, 3652, 7155). Each one of the bins encloses a total of 107 clusters, with the exception of the outermost bin, where 108 objects are in the bin. 3.1.1 Cluster formation rate Our full cluster sample covers ages up to ...
... cluster in our catalogue, we used radial bins with limits of R[pc] = (372, 2153, 2700, 3652, 7155). Each one of the bins encloses a total of 107 clusters, with the exception of the outermost bin, where 108 objects are in the bin. 3.1.1 Cluster formation rate Our full cluster sample covers ages up to ...
Astrophysical X-ray source
Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays.There are a number of types of astrophysical objects which emit X-rays, from galaxy clusters, through black holes in active galactic nuclei (AGN) to galactic objects such as supernova remnants, stars, and binary stars containing a white dwarf (cataclysmic variable stars and super soft X-ray sources), neutron star or black hole (X-ray binaries). Some solar system bodies emit X-rays, the most notable being the Moon, although most of the X-ray brightness of the Moon arises from reflected solar X-rays. A combination of many unresolved X-ray sources is thought to produce the observed X-ray background. The X-ray continuum can arise from bremsstrahlung, either magnetic or ordinary Coulomb, black-body radiation, synchrotron radiation, inverse Compton scattering of lower-energy photons be relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions.Furthermore, celestial entities in space are discussed as celestial X-ray sources. The origin of all observed astronomical X-ray sources is in, near to, or associated with a coronal cloud or gas at coronal cloud temperatures for however long or brief a period.