on the rotational dynamics of magnetically threaded disks around
... numerical studies indicated that the accretion flow around a strongly magnetized object can be nonstationary and episodic in character, the recent MHD simulations by Romanova et al. (2002, hereafter RUKL02) showed that quiescent accretion regimes are also possible, provided a matter-dominated, diffe ...
... numerical studies indicated that the accretion flow around a strongly magnetized object can be nonstationary and episodic in character, the recent MHD simulations by Romanova et al. (2002, hereafter RUKL02) showed that quiescent accretion regimes are also possible, provided a matter-dominated, diffe ...
Galaxies: Interactions and Mergers Encyclopedia of Astronomy & Astrophysics eaa.iop.org C Mihos
... are embedded in massive, extended ‘dark matter halos’. These dark matter halos extend to many tens or even hundreds of kiloparsecs, such that encounters where the luminous galaxies seem to pass by one another may in fact be penetrating encounters for the dark halos. When this happens, dynamical fric ...
... are embedded in massive, extended ‘dark matter halos’. These dark matter halos extend to many tens or even hundreds of kiloparsecs, such that encounters where the luminous galaxies seem to pass by one another may in fact be penetrating encounters for the dark halos. When this happens, dynamical fric ...
Chapter 7 Elliptical Galaxies Chapter 16 Elliptical Galaxies
... 7.1.4 Central regions of elliptical galaxies and bulges They are important for the dynamical structure (population of stellar orbits, see below) of ellipticals and probably all bulges and ellipticals host supermassive black holes (see below). The structure of the central regions seems intimately lin ...
... 7.1.4 Central regions of elliptical galaxies and bulges They are important for the dynamical structure (population of stellar orbits, see below) of ellipticals and probably all bulges and ellipticals host supermassive black holes (see below). The structure of the central regions seems intimately lin ...
Article PDF - IOPscience
... In the Hα image, clouds were searched by visual inspection. Ghosts of bright stars and residuals of background subtractions were carefully checked and excluded. The correlation of R − NB and color (Figure 3) suggested that red galaxies would have residuals in the Hα image, while blue galaxies would ...
... In the Hα image, clouds were searched by visual inspection. Ghosts of bright stars and residuals of background subtractions were carefully checked and excluded. The correlation of R − NB and color (Figure 3) suggested that red galaxies would have residuals in the Hα image, while blue galaxies would ...
SPECTRAL STATE DEPENDENCE OF THE 0.4–2 MEV
... hard state (also known as “low” state, hereafter LHS). In the HSS, the emission is dominated by a bright and warm (∼1 keV) accretion disk, the level of variability is low, and the power density spectrum is power-law like. Little or no radio emission is detected in this state, which is interpreted as ...
... hard state (also known as “low” state, hereafter LHS). In the HSS, the emission is dominated by a bright and warm (∼1 keV) accretion disk, the level of variability is low, and the power density spectrum is power-law like. Little or no radio emission is detected in this state, which is interpreted as ...
Chapter 1
... ratios are higher than a cooler nebula. This is because to produce [O iii] λ4363 an electron needs to be excited to 5.3 eV, which requires more energy than for 4959/5007 which result from decay from 1 D2 level, 2.5 eV above the ground-state (see Figure 2.2). Therefore, these ratios can be used to co ...
... ratios are higher than a cooler nebula. This is because to produce [O iii] λ4363 an electron needs to be excited to 5.3 eV, which requires more energy than for 4959/5007 which result from decay from 1 D2 level, 2.5 eV above the ground-state (see Figure 2.2). Therefore, these ratios can be used to co ...
17 April 2013 When Galaxies Collide Professor Carolin Crawford
... The bulge is a yellowy-white colour, revealing that it is an accumulation of older stars, similar to the population found in an elliptical galaxy. The spiral arms within the disc are notably much bluer, as they trace regions where massive star formation is currently active (blue stars are short-liv ...
... The bulge is a yellowy-white colour, revealing that it is an accumulation of older stars, similar to the population found in an elliptical galaxy. The spiral arms within the disc are notably much bluer, as they trace regions where massive star formation is currently active (blue stars are short-liv ...
Angular momentum and the formation of stars and
... spin angular momentum of this matter must still be removed or redistributed during the star formation process. The excess spin angular momentum of the matter from which each star forms could in principle be transferred to outlying gas or to the orbital motions of other stars, and both magnetic and g ...
... spin angular momentum of this matter must still be removed or redistributed during the star formation process. The excess spin angular momentum of the matter from which each star forms could in principle be transferred to outlying gas or to the orbital motions of other stars, and both magnetic and g ...
Introduction
... volume and mass limited, and includes galaxies of all morphological types inhabiting a range of different environments, from galaxies in the dense core of the Virgo cluster to relatively isolated systems. As such, the sample is ideal for disentangling the internal and environmental processes driving ...
... volume and mass limited, and includes galaxies of all morphological types inhabiting a range of different environments, from galaxies in the dense core of the Virgo cluster to relatively isolated systems. As such, the sample is ideal for disentangling the internal and environmental processes driving ...
the origin of the hubble sequence - Yale Astronomy
... In gravitational theories of spiral structure, the spacing of the arms depends on the quantity λcrit = 4π 2 Gμ/κ2 , which is the maximum wavelength of unstable axisymmetric perturbations in a thin disk (Toomre 1964); it is also approximately the arm spacing for which swing amplification is most impor ...
... In gravitational theories of spiral structure, the spacing of the arms depends on the quantity λcrit = 4π 2 Gμ/κ2 , which is the maximum wavelength of unstable axisymmetric perturbations in a thin disk (Toomre 1964); it is also approximately the arm spacing for which swing amplification is most impor ...
Flare Observations
... Abstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observatio ...
... Abstract Solar flares are observed at all wavelengths from decameter radio waves to gamma-rays at 100 MeV. This review focuses on recent observations in EUV, soft and hard X-rays, white light, and radio waves. Space missions such as RHESSI, Yohkoh, TRACE, and SOHO have enlarged widely the observatio ...
Discovery of a bright quasar without a massive
... This peculiar quasar, therefore, has a host galaxy (if any) that is significantly less luminous than expected from its nuclear luminosity and black hole mass. Moreover, it suffers a strong dynamical interaction with an ultra–luminous infrared galaxy (a rare class of galaxies, systematically involved ...
... This peculiar quasar, therefore, has a host galaxy (if any) that is significantly less luminous than expected from its nuclear luminosity and black hole mass. Moreover, it suffers a strong dynamical interaction with an ultra–luminous infrared galaxy (a rare class of galaxies, systematically involved ...
Particle kinematics in solar flares: observations - ETH E
... Solar flares are amongst the most powerful and energetic activity phenomena our Sun exhibits. They release energy of the order of 1032 erg in seconds to minutes. In the process, electrons and protons are accelerated to relativistic energies, making flares very efficient particle accelerators. The mo ...
... Solar flares are amongst the most powerful and energetic activity phenomena our Sun exhibits. They release energy of the order of 1032 erg in seconds to minutes. In the process, electrons and protons are accelerated to relativistic energies, making flares very efficient particle accelerators. The mo ...
van der Wel et al., 2004, ApJ, 602, L5 - ST-ECF
... to the M∗ mass of an early-type galaxy: if we take the j∗ of early-type galaxies derived by Kochanek (1994) of 225 km s⫺2, we derive a typical mass of M∗ p 3.1 # 10 11 M,, based on the sample measured by Faber et al. 1989. The sample as a whole evolves as D ln (M/L B ) p (⫺1.64 Ⳳ 0.45)z, whereas the ...
... to the M∗ mass of an early-type galaxy: if we take the j∗ of early-type galaxies derived by Kochanek (1994) of 225 km s⫺2, we derive a typical mass of M∗ p 3.1 # 10 11 M,, based on the sample measured by Faber et al. 1989. The sample as a whole evolves as D ln (M/L B ) p (⫺1.64 Ⳳ 0.45)z, whereas the ...
Power Point Presentation
... upper atmosphere, report Stanford researchers. It is the first time that a significant change in Earth's environment has been traced to energy from a distant star. (from the NASA press release) ...
... upper atmosphere, report Stanford researchers. It is the first time that a significant change in Earth's environment has been traced to energy from a distant star. (from the NASA press release) ...
3011800000630
... primarily in the optical and near IR bands. A realistic model for a putative fallback disk should take into account the effects of irradiation by the neutron star’s X-ray luminosity. Irradiation is the dominant source of disk luminosity for the outer disk, at IR and longer wavelengths. The radial te ...
... primarily in the optical and near IR bands. A realistic model for a putative fallback disk should take into account the effects of irradiation by the neutron star’s X-ray luminosity. Irradiation is the dominant source of disk luminosity for the outer disk, at IR and longer wavelengths. The radial te ...
The Current Status of Galaxy Formation
... at least for the “typical” galaxy. The characteristic galactic mass is understood by the requirement that cooling within a dynamical time is a necessary condition for efficient star formation (Fig. 1). However, the naı̈ve assumption that stellar mass follows halo mass, leads to too many small galaxi ...
... at least for the “typical” galaxy. The characteristic galactic mass is understood by the requirement that cooling within a dynamical time is a necessary condition for efficient star formation (Fig. 1). However, the naı̈ve assumption that stellar mass follows halo mass, leads to too many small galaxi ...
Gamma Ray Bursts
... • most of them in 1983.11, some in groups, some single Soon, more SGR discovered • all in our Galaxy • all at SN remnants ~10 000 years old • X-ray oscillations found with ~8s period Puzzle solved in 1998 • in 3 years, the period of SGR 1806-20 decreases by 0.008s • reason – magnetic field calculate ...
... • most of them in 1983.11, some in groups, some single Soon, more SGR discovered • all in our Galaxy • all at SN remnants ~10 000 years old • X-ray oscillations found with ~8s period Puzzle solved in 1998 • in 3 years, the period of SGR 1806-20 decreases by 0.008s • reason – magnetic field calculate ...
The 8190-A sodium doublet in cataclysmic variables
... (WHT), we proposed a further survey, of fainter objects, to improve the statistics and to find new systems for detailed study. The new survey, which we present here, covers a much larger range of wavelength than the previous one, at a somewhat lower resolution. In most cases, only a few spectra were ...
... (WHT), we proposed a further survey, of fainter objects, to improve the statistics and to find new systems for detailed study. The new survey, which we present here, covers a much larger range of wavelength than the previous one, at a somewhat lower resolution. In most cases, only a few spectra were ...
GRB prompt emission
... Hosts! • Hosts of long GRBs are star-forming galaxies • GRBs trace the stellar distribution (in distance from galaxy center) • GRBs occur in dense environments (star forming regions?) ...
... Hosts! • Hosts of long GRBs are star-forming galaxies • GRBs trace the stellar distribution (in distance from galaxy center) • GRBs occur in dense environments (star forming regions?) ...
Non-thermal emission processes in massive binaries*
... - the emission of thermal X-rays, likely produced by hydrodynamic shocks between plasma shells travelling at different velocities in the wind of isolated stars, and leading to local temperature enhancements of a few 106 K (see Feldmeier et al (1997)). The thermal nature of the X-rays produced within ...
... - the emission of thermal X-rays, likely produced by hydrodynamic shocks between plasma shells travelling at different velocities in the wind of isolated stars, and leading to local temperature enhancements of a few 106 K (see Feldmeier et al (1997)). The thermal nature of the X-rays produced within ...
GRB prompt emission
... Hosts! • Hosts of long GRBs are star-forming galaxies • GRBs trace the stellar distribution (in distance from galaxy center) • GRBs occur in dense environments (star forming regions?) ...
... Hosts! • Hosts of long GRBs are star-forming galaxies • GRBs trace the stellar distribution (in distance from galaxy center) • GRBs occur in dense environments (star forming regions?) ...
Zinc and chromium abundances in a third
... in Q0454+039 (Steidel et al. 1995). The fields of both QSOs have been imaged from the ground (Steidel et al. 1994, 1995) and with the Hubble Space Telescope (Le Brun et al. 1997), and plausible candidates for the absorbing galaxies have been identified. However, in neither case is a Milky Way-type g ...
... in Q0454+039 (Steidel et al. 1995). The fields of both QSOs have been imaged from the ground (Steidel et al. 1994, 1995) and with the Hubble Space Telescope (Le Brun et al. 1997), and plausible candidates for the absorbing galaxies have been identified. However, in neither case is a Milky Way-type g ...
The binary fraction of the young cluster NGC 1818 in the Large
... of stars place important constraints on star formation and the origin of the stellar initial mass function (IMF; Goodwin et al. 2007, 2008). The majority of stars with masses greater than approximately 0.5M are also thought to form in star clusters (Lada & Lada 2003), and the binary content of a st ...
... of stars place important constraints on star formation and the origin of the stellar initial mass function (IMF; Goodwin et al. 2007, 2008). The majority of stars with masses greater than approximately 0.5M are also thought to form in star clusters (Lada & Lada 2003), and the binary content of a st ...
JENAM-2011 Book of abstracts
... background, ∼7-10%. Underneath bright X-ray binaries, unresolved emission is present in all types of galaxies, which is partly due to unresolved faint compact sources, including accreting white dwarfs. The luminosity of unresolved emission and statistics of classical novae can be used to place an up ...
... background, ∼7-10%. Underneath bright X-ray binaries, unresolved emission is present in all types of galaxies, which is partly due to unresolved faint compact sources, including accreting white dwarfs. The luminosity of unresolved emission and statistics of classical novae can be used to place an up ...
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.