Spiral galaxies - Ira-Inaf
... to >109 Msun. The extraordinary case of NGC 1961 (Combes+ 2009) has M(H2)~2x1010 Msun. M(dyn) ~ RV2/G. M(H2)/M(dyn) from a few percent up to > 20%. This means that more than 1/5 of the mass in the central few kpc of a galaxy can be molecular gas! There is no unique morphology associated with central ...
... to >109 Msun. The extraordinary case of NGC 1961 (Combes+ 2009) has M(H2)~2x1010 Msun. M(dyn) ~ RV2/G. M(H2)/M(dyn) from a few percent up to > 20%. This means that more than 1/5 of the mass in the central few kpc of a galaxy can be molecular gas! There is no unique morphology associated with central ...
Origin of close binary systems
... - example: the multiplicities of the Orion Trapezium stars and the companion star frequency of high-mass vs. low-mass stars - SPH simulations: hierarchical star cluster formation and the merging of subclusters as a model for the origin of Trapezia - origin due to formation or early dynamical N-body ...
... - example: the multiplicities of the Orion Trapezium stars and the companion star frequency of high-mass vs. low-mass stars - SPH simulations: hierarchical star cluster formation and the merging of subclusters as a model for the origin of Trapezia - origin due to formation or early dynamical N-body ...
Document
... because the gravity of these stars is not strong enough to make general relativistic effects substantial.) As such, they may also be expected to have a maximum mass, as white dwarfs do. For stars more massive than this maximum, neutron degeneracy pressure will not prevent the formation of black ho ...
... because the gravity of these stars is not strong enough to make general relativistic effects substantial.) As such, they may also be expected to have a maximum mass, as white dwarfs do. For stars more massive than this maximum, neutron degeneracy pressure will not prevent the formation of black ho ...
Physical properties of Hα selected star forming galaxies at z ~ 0.84
... In a first step, 239 emission line candidates were selected (once excluded the stars) by their flux excess in the narrow band, showing a J − JC colour excess significance nσ > 2.5 in one or several apertures. Spectroscopic and photometric redshifts were then used to rule out contaminants, either emi ...
... In a first step, 239 emission line candidates were selected (once excluded the stars) by their flux excess in the narrow band, showing a J − JC colour excess significance nσ > 2.5 in one or several apertures. Spectroscopic and photometric redshifts were then used to rule out contaminants, either emi ...
Astronomy Astrophysics − Orbital phase-resolved spectroscopy of 4U 1538
... Context. 4U 1538−52, an absorbed high mass X-ray binary with an orbital period of ∼3.73 days, shows moderate orbital intensity modulations with a low level of counts during the eclipse. Several models have been proposed to explain the accretion at different orbital phases by a spherically symmetric s ...
... Context. 4U 1538−52, an absorbed high mass X-ray binary with an orbital period of ∼3.73 days, shows moderate orbital intensity modulations with a low level of counts during the eclipse. Several models have been proposed to explain the accretion at different orbital phases by a spherically symmetric s ...
Article PDF - IOPscience
... Although data on external galaxies are fewer and much less detailed, they have still allowed their study with the use of similar methods. However, the number of parameters involved in any chemical evolution model is large, and a unique solution to the problem does not exist. Even the evolutionary pi ...
... Although data on external galaxies are fewer and much less detailed, they have still allowed their study with the use of similar methods. However, the number of parameters involved in any chemical evolution model is large, and a unique solution to the problem does not exist. Even the evolutionary pi ...
The Triple-Ring Nebula: Fingerprint of a Binary Merger
... to decrease, just as an ice-skater starts to spin more slowly when extending her arms at the end of a pirouette. ...
... to decrease, just as an ice-skater starts to spin more slowly when extending her arms at the end of a pirouette. ...
Star Formation in the Galactic Center
... ‘normal’ (Nayakshin et al (2005) star formation at several parsecs away from GC in a massive cluster that then spirals in. This would avoid the need for excessive gas density in order to form stars. Cluster would orbit through background stars, decay through friction, and settle in center cont ...
... ‘normal’ (Nayakshin et al (2005) star formation at several parsecs away from GC in a massive cluster that then spirals in. This would avoid the need for excessive gas density in order to form stars. Cluster would orbit through background stars, decay through friction, and settle in center cont ...
Cosmological dynamics with non-minimally coupled scalar field and
... components in order to distinguish spectroscopic pairs from false pairs created by projection along the line of sight. Of six pair candidates observed, companions (estimated mass ratios 5:1 and 7:1) are detected for two galaxies down to a 3σ limiting emission-line flux of ∼ 10−17 erg s−1 cm−2 . This ...
... components in order to distinguish spectroscopic pairs from false pairs created by projection along the line of sight. Of six pair candidates observed, companions (estimated mass ratios 5:1 and 7:1) are detected for two galaxies down to a 3σ limiting emission-line flux of ∼ 10−17 erg s−1 cm−2 . This ...
are coronae of late-type stars made of solar-like structures? the x
... particular, this work shows that stellar coronae can be composed of X-ray–emitting structures similar to those present in the solar corona. To this end we use a large set of ROSAT PSPC observations of late-type stars of all spectral types and activity levels and a large set of solar X-ray data colle ...
... particular, this work shows that stellar coronae can be composed of X-ray–emitting structures similar to those present in the solar corona. To this end we use a large set of ROSAT PSPC observations of late-type stars of all spectral types and activity levels and a large set of solar X-ray data colle ...
Chapter 22 PowerPoint
... Distance measurements of some gamma bursts show them to be very far away—2 billion parsecs for the first one measured. Occasionally the spectrum of a burst can be measured, allowing distance determination: ...
... Distance measurements of some gamma bursts show them to be very far away—2 billion parsecs for the first one measured. Occasionally the spectrum of a burst can be measured, allowing distance determination: ...
2 workshop on X-ray and XUV active optics
... ESRF Optical Metrology Applied to bent optical surfaces ...
... ESRF Optical Metrology Applied to bent optical surfaces ...
Andromeda and the Local Group Lesson Plan
... Way, and we’ll take a closer look at some of the nebula inside galaxies that are orbiting our own. Show the video. Review what they saw: ...
... Way, and we’ll take a closer look at some of the nebula inside galaxies that are orbiting our own. Show the video. Review what they saw: ...
First Light: Physical Characterization of Early Star Formation in the
... The Milky Way has shaped the modern view that galaxies form hierarchically through the merging of clumps of gas and stars, accompanied by slower accretion of gas. In this picture, dwarf galaxies may represent protogalactic fragments that have not yet been accreted into larger galaxies. However, a re ...
... The Milky Way has shaped the modern view that galaxies form hierarchically through the merging of clumps of gas and stars, accompanied by slower accretion of gas. In this picture, dwarf galaxies may represent protogalactic fragments that have not yet been accreted into larger galaxies. However, a re ...
Astronomy Astrophysics Astrophysical parameters and orbital solution of the peculiar X-ray
... 2006b) as a sub-class of SGXBs. SFXTs spend most of their time at X-ray luminosities between LX ∼ 1032 to 1034 erg s−1 , well below the “normal” X-ray luminosity of SGXBs, with very brief excursions to outburst luminosities of up to a few times 1036 erg s−1 (e.g. Rampy et al. 2009; Sidoli et al. 200 ...
... 2006b) as a sub-class of SGXBs. SFXTs spend most of their time at X-ray luminosities between LX ∼ 1032 to 1034 erg s−1 , well below the “normal” X-ray luminosity of SGXBs, with very brief excursions to outburst luminosities of up to a few times 1036 erg s−1 (e.g. Rampy et al. 2009; Sidoli et al. 200 ...
Sample
... center of the Milky Way galaxy harbors a supermassive black hole. A black hole actually is a hole in the observable universe, a region of space where gravity has become so strong that nothing, not even light, can ever escape. The tremendous gravitational pull of a black hole originates from its imme ...
... center of the Milky Way galaxy harbors a supermassive black hole. A black hole actually is a hole in the observable universe, a region of space where gravity has become so strong that nothing, not even light, can ever escape. The tremendous gravitational pull of a black hole originates from its imme ...
Galaxies and the Distance Ladder
... Which of the following is NOT a reason why astronomers believe that dark matter exists? A. They can detect it with radio telescopes. B. The outer parts of galaxies rotate faster than expected on the basis of the luminous matter. C. The galaxies in clusters move faster than expected on the basis of t ...
... Which of the following is NOT a reason why astronomers believe that dark matter exists? A. They can detect it with radio telescopes. B. The outer parts of galaxies rotate faster than expected on the basis of the luminous matter. C. The galaxies in clusters move faster than expected on the basis of t ...
Document
... number of astrophysical phenomena which are otherwise difficult to understand. Binaries provide an explanation for Type Ia supernovae. These are thought to be a consequence of accretion onto a white dwarf. Binaries explain why the progenitor of SN1987A was a blue supergiant: its outer envelope was l ...
... number of astrophysical phenomena which are otherwise difficult to understand. Binaries provide an explanation for Type Ia supernovae. These are thought to be a consequence of accretion onto a white dwarf. Binaries explain why the progenitor of SN1987A was a blue supergiant: its outer envelope was l ...
Optical Variability of Hercules X-1/HZ Herculis
... jun1702 June 19 jun1902 June 19 jun1904 June 20 jun2002 June 20 jun2004 June 21 jun2103 June 21 jun2104 June 22 jun2203 June 23 jun2305 ...
... jun1702 June 19 jun1902 June 19 jun1904 June 20 jun2002 June 20 jun2004 June 21 jun2103 June 21 jun2104 June 22 jun2203 June 23 jun2305 ...
Full-Text PDF
... down in less than a hundred seconds. It is usually argued that the balance of magnetic pressure with ram pressure from the disk can give an estimate of the possible magnetic flux accumulated around the central object. This argument is reasonable for accreting black hole systems such as AGNs and X-ra ...
... down in less than a hundred seconds. It is usually argued that the balance of magnetic pressure with ram pressure from the disk can give an estimate of the possible magnetic flux accumulated around the central object. This argument is reasonable for accreting black hole systems such as AGNs and X-ra ...
Nucleosynthesis of heavy elements in gamma ray bursts
... direct method for probing supernova blasts than observing non-radioactive elements. This is because this radioactive material glows with X-rays no matter what, while the Xrays detected by Chandra and other telescopes are generated only after heating with shock waves from the explosion. Because the n ...
... direct method for probing supernova blasts than observing non-radioactive elements. This is because this radioactive material glows with X-rays no matter what, while the Xrays detected by Chandra and other telescopes are generated only after heating with shock waves from the explosion. Because the n ...
Cooling neutron star in the Cassiopeia A supernova remnant
... • Cas A NS and other isolated neutron stars ...
... • Cas A NS and other isolated neutron stars ...
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.