A self-consistent model of isolated neutron stars: the case of the X
... Bonazzola & Gourgoulhon (1996) for the fully non-linear case. For the general case with both poloidal and toroidal components, a similar non-linear (although Newtonian) analysis is presented in Tomimura & Eriguchi (2005) where Eq. (1) is generalized by considering µ = µ(x) as a general function of x ...
... Bonazzola & Gourgoulhon (1996) for the fully non-linear case. For the general case with both poloidal and toroidal components, a similar non-linear (although Newtonian) analysis is presented in Tomimura & Eriguchi (2005) where Eq. (1) is generalized by considering µ = µ(x) as a general function of x ...
SPACETIME SINGULARITIES: The STORY of BLACK HOLES
... (ii) the discovery in 1962 of quasars, or QSO’s (short for ”quasi-stellar objects”); these looked like stars, but had colossal redshifts, apparently placing them billions of light years away; (iii) the discovery in 1967 of pulsars (named thus because of their very rapid pulsing, sometimes with perio ...
... (ii) the discovery in 1962 of quasars, or QSO’s (short for ”quasi-stellar objects”); these looked like stars, but had colossal redshifts, apparently placing them billions of light years away; (iii) the discovery in 1967 of pulsars (named thus because of their very rapid pulsing, sometimes with perio ...
RED DWARFS AND THE END OF THE MAIN SEQUENCE
... provide another opportunity for life to flourish. The galaxy continues to make new stars until it runs out of gas, both literally and figuratively. With the current rate of star formation, and the current supply of hydrogen gas, the galaxy would run of gas in only a Hubble time or two. Fortunately, ...
... provide another opportunity for life to flourish. The galaxy continues to make new stars until it runs out of gas, both literally and figuratively. With the current rate of star formation, and the current supply of hydrogen gas, the galaxy would run of gas in only a Hubble time or two. Fortunately, ...
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... on the contrary, the strongest radio outbursts are always delayed with respect to (Taylor et al. 1996; Gregory et al. 1999). Both the presence of two periodicities (at 26.5 days and ∼4 years) and the delay between radio and X-ray outbursts are well explained in the framework of an accretion scenario ...
... on the contrary, the strongest radio outbursts are always delayed with respect to (Taylor et al. 1996; Gregory et al. 1999). Both the presence of two periodicities (at 26.5 days and ∼4 years) and the delay between radio and X-ray outbursts are well explained in the framework of an accretion scenario ...
A Reservoir of Ionized Gas in the Galactic Halo to Sustain Star
... The timescale for gas consumption via star formation in spiral galaxies is far shorter than a Hubble time (13.8 billion years), requiring an on-going replenishment of the gaseous fuel in the disks of galaxies for continued star formation. Analytical models and hydrodynamical simulations have emphasi ...
... The timescale for gas consumption via star formation in spiral galaxies is far shorter than a Hubble time (13.8 billion years), requiring an on-going replenishment of the gaseous fuel in the disks of galaxies for continued star formation. Analytical models and hydrodynamical simulations have emphasi ...
The Universe - the Scientia Review
... Galactic interaction occurs when one galaxy is distorted by another. It appears by a variety of processes, including satellite interaction, galactic collision, and galactic cannibalism. Satellite interaction, which is found in smaller galaxies orbiting larger counterparts, can affect both the satell ...
... Galactic interaction occurs when one galaxy is distorted by another. It appears by a variety of processes, including satellite interaction, galactic collision, and galactic cannibalism. Satellite interaction, which is found in smaller galaxies orbiting larger counterparts, can affect both the satell ...
Design and Preparation for a Balloon
... state which quickly decays by emitting X-rays of precisely defined energy and a correlated pion signature from nuclear annihilation. The GAPS method of using this combined X-ray and pion signature to uniquely identify antiparticles has been verified through accelerator testing of a prototype detecto ...
... state which quickly decays by emitting X-rays of precisely defined energy and a correlated pion signature from nuclear annihilation. The GAPS method of using this combined X-ray and pion signature to uniquely identify antiparticles has been verified through accelerator testing of a prototype detecto ...
The Milky Way Galaxy - d_smith.lhseducators.com
... – Contains almost exclusively VERY old stars (population II stars). – These stars are low in heavy elements, meaning that they’re as old as the ...
... – Contains almost exclusively VERY old stars (population II stars). – These stars are low in heavy elements, meaning that they’re as old as the ...
Role of column density in the formation of stars
... For disc galaxies, the model assumes that a galaxy acquires most of its mass in a time that is short compared with the time required for the gas to turn into stars, and that the dark matter quickly settles into an isothermal sphere and the gas into a disc with the same radial mass distribution. Alth ...
... For disc galaxies, the model assumes that a galaxy acquires most of its mass in a time that is short compared with the time required for the gas to turn into stars, and that the dark matter quickly settles into an isothermal sphere and the gas into a disc with the same radial mass distribution. Alth ...
Test 4 Review
... weightless. Einstein says these are equivalent. So in freefall, light and ball also travel in straight lines. 3. Now imagine two people in freefall on Earth, passing a ball back and forth. From their perspective, they pass it in a straight line. From a stationary perspective, it follows a curved pat ...
... weightless. Einstein says these are equivalent. So in freefall, light and ball also travel in straight lines. 3. Now imagine two people in freefall on Earth, passing a ball back and forth. From their perspective, they pass it in a straight line. From a stationary perspective, it follows a curved pat ...
Dark Matter Capture in the first stars
... • They would be adiabatically contracted into the stars and then sink to the center by dynamical friction, creating a larger black hole which may swallow the whole star. End result: 10-1000 solar mass BH, which may serve as seeds for early big BH or for BH in galaxies. ...
... • They would be adiabatically contracted into the stars and then sink to the center by dynamical friction, creating a larger black hole which may swallow the whole star. End result: 10-1000 solar mass BH, which may serve as seeds for early big BH or for BH in galaxies. ...
The Role of the Galaxy in the Dynamical Evolution of
... •Young (1-5 Myr) star-forming regions, fraction of mass in stars ~1030% • Difficult to observe in the visible; most done in the IR •Very dense environment (typically 102-103 Msun pc-3 in stars; but Trapezium and others have >104 Msun pc-3 in stars - e.g. Gutherman et al 2005 find 24-91% of stars in ...
... •Young (1-5 Myr) star-forming regions, fraction of mass in stars ~1030% • Difficult to observe in the visible; most done in the IR •Very dense environment (typically 102-103 Msun pc-3 in stars; but Trapezium and others have >104 Msun pc-3 in stars - e.g. Gutherman et al 2005 find 24-91% of stars in ...
What keeps stars shining? What holds them up? Lecture 14. The
... "perfect gas" it takes a higher core temperature to maintain the same pressure. As core temperature rises, fusion rate rises, so luminosity increases somewhat. (This is very important for understanding origin of life on earth. Sun's luminosity has grown at least 50% since birth of Earth. Planetary s ...
... "perfect gas" it takes a higher core temperature to maintain the same pressure. As core temperature rises, fusion rate rises, so luminosity increases somewhat. (This is very important for understanding origin of life on earth. Sun's luminosity has grown at least 50% since birth of Earth. Planetary s ...
Surface temperature distribution and absorption features in Isolated
... disk emits; a weak magnetic field does not make the conductivity too much anisotropic, so the temperature could be considered constant on the whole surface. There are some binary systems, known as soft x-ray transients, where the NS orbits a Be star in a very eccentric orbit, accreting material only ...
... disk emits; a weak magnetic field does not make the conductivity too much anisotropic, so the temperature could be considered constant on the whole surface. There are some binary systems, known as soft x-ray transients, where the NS orbits a Be star in a very eccentric orbit, accreting material only ...
Comparison between the luminosity functions of X
... for all sources with a reliable Seyfert classification. There are 38 sources in the sample, of which 30 are classified as type2 and eight as type-1. We correct the X-ray luminosities for absorption using the observed column densities given in that paper. There are five Seyfert-2 galaxies which do no ...
... for all sources with a reliable Seyfert classification. There are 38 sources in the sample, of which 30 are classified as type2 and eight as type-1. We correct the X-ray luminosities for absorption using the observed column densities given in that paper. There are five Seyfert-2 galaxies which do no ...
Chapter 4 On the possibility of a helium white dwarf donor in the
... Second, it has an X-ray luminosity which is low for an active LMXB, namely less than or equal to 1% of the Eddington limit for a canonical (1.4 M⊙ , 10 km radius) neutron star (Jonker et al. 2001). Third, 2S 0918–549 appears to have an unusually high Ne/O abundance ratio, a characteristic which it s ...
... Second, it has an X-ray luminosity which is low for an active LMXB, namely less than or equal to 1% of the Eddington limit for a canonical (1.4 M⊙ , 10 km radius) neutron star (Jonker et al. 2001). Third, 2S 0918–549 appears to have an unusually high Ne/O abundance ratio, a characteristic which it s ...
HWWS 2010 - Monash University
... • Latter two are both likely classes of magnetars, (possibly young) systems with extremely high magnetic fields 1014– 1015 G • Compact central objects (CCOs) about which very little is known, associated with supernova remnants Galloway, “Accreting Neutron Stars – tiny Galactic Powerhouses” ...
... • Latter two are both likely classes of magnetars, (possibly young) systems with extremely high magnetic fields 1014– 1015 G • Compact central objects (CCOs) about which very little is known, associated with supernova remnants Galloway, “Accreting Neutron Stars – tiny Galactic Powerhouses” ...
English - Wise Observatory
... Israeli astronomers find a dark matter filament close to the Milky Way Observations performed recently at Tel Aviv University’s Wise Observatory indicate that intergalactic gas is concentrated by dark matter and forms galaxies. The scientists studied in detail nearby galaxies and the results have im ...
... Israeli astronomers find a dark matter filament close to the Milky Way Observations performed recently at Tel Aviv University’s Wise Observatory indicate that intergalactic gas is concentrated by dark matter and forms galaxies. The scientists studied in detail nearby galaxies and the results have im ...
Fossil Galaxies
... star formation. The first panel shows the thousands of dark-matter clumps that coexist with our galaxy. The second panel highlights in green those dark-matter clumps massive enough to obtain gas from the intergalactic medium and trigger star formation, eventually creating dwarf galaxies. The third p ...
... star formation. The first panel shows the thousands of dark-matter clumps that coexist with our galaxy. The second panel highlights in green those dark-matter clumps massive enough to obtain gas from the intergalactic medium and trigger star formation, eventually creating dwarf galaxies. The third p ...
ppt - chris.engelbrecht.nithep.ac.za
... • This SNR is detected directly in TeV gamma-rays, by HESS - first resolved image of an SNR at TeV energies ...
... • This SNR is detected directly in TeV gamma-rays, by HESS - first resolved image of an SNR at TeV energies ...
3011800000360
... Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are neutron stars that are characterized by persistent X-ray luminosities (L 1034 1036 ergs s1) well above their rotation powers (see Mereghetti et al. 2002; Hurley 2000 for reviews of AXPs and SGRs, respectively). Another remarka ...
... Anomalous X-ray pulsars (AXPs) and soft gamma-ray repeaters (SGRs) are neutron stars that are characterized by persistent X-ray luminosities (L 1034 1036 ergs s1) well above their rotation powers (see Mereghetti et al. 2002; Hurley 2000 for reviews of AXPs and SGRs, respectively). Another remarka ...
Population synthesis of Be/white dwarf binaries in the Galaxy
... systems) we study the number and physical properties of binary Be stars with white dwarfs taking account of the compact object cooling and we discuss the ways of their formation. In our calculations we take into account the influence of tidal synchronization on the evolution of stars in a close bina ...
... systems) we study the number and physical properties of binary Be stars with white dwarfs taking account of the compact object cooling and we discuss the ways of their formation. In our calculations we take into account the influence of tidal synchronization on the evolution of stars in a close bina ...
Accreting neutron stars: strong gravity and type I bursts - UvA-DARE
... radius1 . In consequence, we can obtain strong constraints on the nature of the EOS by measuring mass and radius of NSs. In general, the outer crust is thought to be made of a lattice of ions and (increasingly) relativistic, degenerate electrons. Where the density reaches the threshold of neutron dr ...
... radius1 . In consequence, we can obtain strong constraints on the nature of the EOS by measuring mass and radius of NSs. In general, the outer crust is thought to be made of a lattice of ions and (increasingly) relativistic, degenerate electrons. Where the density reaches the threshold of neutron dr ...
low surface brightness galaxies
... In more recent years, a large body of observational evidence has been collected that demonstrates that interactions and mergers indeed represent a common phenomenon at high redshifts, and that these processes affect the population of elliptical galaxies in the local Universe. ...
... In more recent years, a large body of observational evidence has been collected that demonstrates that interactions and mergers indeed represent a common phenomenon at high redshifts, and that these processes affect the population of elliptical galaxies in the local Universe. ...
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.