Galaxies
... • Many of these galaxies have powerful radio sources at their centers. This indicates the presence of a supermassive black hole as the power source. These are now called AGN: Active Galactic Nuclei ...
... • Many of these galaxies have powerful radio sources at their centers. This indicates the presence of a supermassive black hole as the power source. These are now called AGN: Active Galactic Nuclei ...
Neutron stars as probes of extreme energy density matter
... trace elements of H with a finely tuned mass (origin unknown) are required to adequately fit the data. Despite much promise, reliable extractions of M and R from isolated neutron stars await further developments in the treatment of atmospheres, and additional data. The magnificence of the seven is y ...
... trace elements of H with a finely tuned mass (origin unknown) are required to adequately fit the data. Despite much promise, reliable extractions of M and R from isolated neutron stars await further developments in the treatment of atmospheres, and additional data. The magnificence of the seven is y ...
Key paper.
... appears more extended than the dust emission, with a brightness profile that is better resolved. Dust probably extends out to the same limits as the gas but, owing to different emissivity properties, it is not readily detectable at such distances from the star. The outer region of the molecular emis ...
... appears more extended than the dust emission, with a brightness profile that is better resolved. Dust probably extends out to the same limits as the gas but, owing to different emissivity properties, it is not readily detectable at such distances from the star. The outer region of the molecular emis ...
From: BXSVR0::OWOCKI 12-JAN-2001 10:16:41.12 To: DCOHEN
... a good one: metastable levels do get populated, and collisions (and even some radiative transitions in the UV that affect X-ray lines -- see Wayne and Joe's recent paper on zeta Ori) can be important between excited levels -- this can affect details of individual line ratios, etc., but not the overa ...
... a good one: metastable levels do get populated, and collisions (and even some radiative transitions in the UV that affect X-ray lines -- see Wayne and Joe's recent paper on zeta Ori) can be important between excited levels -- this can affect details of individual line ratios, etc., but not the overa ...
1e 1048.1−5937, xte j1810−197 and 4u 0142+61
... effect the observed location of the line; the mass of the QS and the inclination of the disk. We will assume a mass of 1.5 M⊙ and derive the inclination. As mentioned above, a layer of non-degenerate Keplerian material is unveiled during an AXP burst. This material is heated to 4–5 keV and is a poss ...
... effect the observed location of the line; the mass of the QS and the inclination of the disk. We will assume a mass of 1.5 M⊙ and derive the inclination. As mentioned above, a layer of non-degenerate Keplerian material is unveiled during an AXP burst. This material is heated to 4–5 keV and is a poss ...
L31 ON THE DISAPPEARANCE OF KILOHERTZ QUASI
... at the last stable orbit and yet the magnetosphere is pushed farther inward. The threshold is therefore dependent on the magnetic field strength—the stronger the magnetic field, the higher the threshold. This is certainly in agreement with the atoll/Z paradigm, but we argue that it is also generally ...
... at the last stable orbit and yet the magnetosphere is pushed farther inward. The threshold is therefore dependent on the magnetic field strength—the stronger the magnetic field, the higher the threshold. This is certainly in agreement with the atoll/Z paradigm, but we argue that it is also generally ...
Driving downsizing with galaxy groups
... • Blue galaxies are absent above ~3x1010 MSun • Star formation today occurs in low-mass galaxies ...
... • Blue galaxies are absent above ~3x1010 MSun • Star formation today occurs in low-mass galaxies ...
The extreme ultraviolet and X-ray Sun in Time: High
... The large differences in the evolutionary tracks, and therefore LX and LEUV values, make it necessary to reconsider critically the atmospheric erosion of planets by high-energy radiation. To a first approximation, the thermal mass loss rate from a simple hydrogen dominated planetary atmosphere, Ṁpl ...
... The large differences in the evolutionary tracks, and therefore LX and LEUV values, make it necessary to reconsider critically the atmospheric erosion of planets by high-energy radiation. To a first approximation, the thermal mass loss rate from a simple hydrogen dominated planetary atmosphere, Ṁpl ...
A wide Chandra view of the core of the Perseus cluster
... They imply that bubbles are long-lived and do not readily breakup when rising in the hot cluster atmosphere. The existence of a 300 kpc long NNW–SSW bubble axis means there cannot be significant transverse large scale flows exceeding 100 km s−1 . Interesting spatial correlations are seen along that ...
... They imply that bubbles are long-lived and do not readily breakup when rising in the hot cluster atmosphere. The existence of a 300 kpc long NNW–SSW bubble axis means there cannot be significant transverse large scale flows exceeding 100 km s−1 . Interesting spatial correlations are seen along that ...
Lab 7: Galaxies
... has a large central bulge with tightly wound and poorly defined spiral arms, so it is hard to distinguish one arm from another through the whole disk. An Sc or SBc galaxy has a smaller core, and open welldefined arms. Sb and SBb galaxies fall in between “a” and “c” classes with medium bulges, and we ...
... has a large central bulge with tightly wound and poorly defined spiral arms, so it is hard to distinguish one arm from another through the whole disk. An Sc or SBc galaxy has a smaller core, and open welldefined arms. Sb and SBb galaxies fall in between “a” and “c” classes with medium bulges, and we ...
Lecture 2. Thermal evolution and surface emission of neutron stars
... During high-state accretion episodes, the heat is deposited by nonequilibrium processes in the deep layers (1012 -1013 g cm-3) of the crust. This deep crustal heating can maintain the temperature of the neutron star interior at a sufficiently high level to explain a persistent thermal X-ray radiatio ...
... During high-state accretion episodes, the heat is deposited by nonequilibrium processes in the deep layers (1012 -1013 g cm-3) of the crust. This deep crustal heating can maintain the temperature of the neutron star interior at a sufficiently high level to explain a persistent thermal X-ray radiatio ...
The MAGNUM survey: positive feedback in the nuclear region of
... In the presence of young- or intermediate-age stellar populations, which present intense Balmer absorption (e.g., EW(Hβ) can reach up to 8 Å), a careful subtraction of the underlying stellar continuum is important to recover the correct emission line fluxes and profiles. Although the optimal approac ...
... In the presence of young- or intermediate-age stellar populations, which present intense Balmer absorption (e.g., EW(Hβ) can reach up to 8 Å), a careful subtraction of the underlying stellar continuum is important to recover the correct emission line fluxes and profiles. Although the optimal approac ...
sun.galaxy.notes
... Milky Way Galaxy • Contains over 200 billion stars • The visible disk of stars is about 100,000 light years across • The sun is located 30,000 light years out from its center • All stars orbit around the central region • Based on a distance of 30,000 light-years and a speed of 235 kilometers a seco ...
... Milky Way Galaxy • Contains over 200 billion stars • The visible disk of stars is about 100,000 light years across • The sun is located 30,000 light years out from its center • All stars orbit around the central region • Based on a distance of 30,000 light-years and a speed of 235 kilometers a seco ...
gravitational collapse to black holes
... If we have a stellar model and constantly add mass to it, any point dM/drho = 0 will in practice imply that the sequence ends there, that is, the star will either collapse or expand exponentially when adding further mass; typically, the inward ram pressure of material (and loss of internal ...
... If we have a stellar model and constantly add mass to it, any point dM/drho = 0 will in practice imply that the sequence ends there, that is, the star will either collapse or expand exponentially when adding further mass; typically, the inward ram pressure of material (and loss of internal ...
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... Starburst can drive winds of enriched gas (e.g., from supernova ejecta) out to the intergalactic medium. This gas can then be accreted again by galaxies. In a disk galaxy, the winds are generally bipolar outflows ...
... Starburst can drive winds of enriched gas (e.g., from supernova ejecta) out to the intergalactic medium. This gas can then be accreted again by galaxies. In a disk galaxy, the winds are generally bipolar outflows ...
"Characterization of 3D-integrated Active Pixel Sensor for X-ray Detection."
... A popular method to measure this crosstalk is pixel correlation analysis [9]–[11]. This involves a complex mathematical treatment and, importantly, assumes symmetrical crosstalk to the left and to the right. We found that the latter assumption is not valid in our sensor. X-ray detection is a direct ...
... A popular method to measure this crosstalk is pixel correlation analysis [9]–[11]. This involves a complex mathematical treatment and, importantly, assumes symmetrical crosstalk to the left and to the right. We found that the latter assumption is not valid in our sensor. X-ray detection is a direct ...
26.3 Life Cycles of Stars
... Low- and Medium-Mass Stars Low-mass and medium-mass stars, which can be as much as eight times as massive as the sun, eventually turn into white dwarfs. • Stars remain in the giant stage until their hydrogen and helium supplies dwindle and there are no other elements to fuse. • The energy coming fro ...
... Low- and Medium-Mass Stars Low-mass and medium-mass stars, which can be as much as eight times as massive as the sun, eventually turn into white dwarfs. • Stars remain in the giant stage until their hydrogen and helium supplies dwindle and there are no other elements to fuse. • The energy coming fro ...
Astronomy Astrophysics A VLT/FLAMES survey for massive binaries in Westerlund 1 &
... the project methodology, reduction technique and preliminary results may be found in Ritchie et al. (2009). In this paper we present an analysis of the properties of the WC9d star W239 (=WR F, WR77n), for which binarity was suggested by the presence of a hard X-ray spectrum and a pronounced near-mid ...
... the project methodology, reduction technique and preliminary results may be found in Ritchie et al. (2009). In this paper we present an analysis of the properties of the WC9d star W239 (=WR F, WR77n), for which binarity was suggested by the presence of a hard X-ray spectrum and a pronounced near-mid ...
XMM-Newton discovery of 7 s pulsations in the isolated neutron star
... The distributions that we obtained for the Z2 statistics are shown in Fig. 2, where it can be seen that a maximum of Z2 is always present at the expected pulse period. To evaluate the statistical significance of these detections, we must take into account the number of periods searched in each obser ...
... The distributions that we obtained for the Z2 statistics are shown in Fig. 2, where it can be seen that a maximum of Z2 is always present at the expected pulse period. To evaluate the statistical significance of these detections, we must take into account the number of periods searched in each obser ...
Metallicity maps
... Ram-pressure stripping can produce considerably more metals than galactic winds (depending on cluster mass and other cluster properties) Schindler et al. 2005, Kapferer et al. 2007, 2009 ...
... Ram-pressure stripping can produce considerably more metals than galactic winds (depending on cluster mass and other cluster properties) Schindler et al. 2005, Kapferer et al. 2007, 2009 ...
Radio-loud ROSAT sources near the North Ecliptic Pole
... groups containing a radio galaxy. Optical magnitudes range from B ' 14 to B > 22. Three results are noteworthy: (1) the bimodality in the ratio of radio to optical emission seen in optically- and X-ray-selected AGN samples is also evident in the ROSAT-VLA objects; (2) X-ray and radio selection is an ...
... groups containing a radio galaxy. Optical magnitudes range from B ' 14 to B > 22. Three results are noteworthy: (1) the bimodality in the ratio of radio to optical emission seen in optically- and X-ray-selected AGN samples is also evident in the ROSAT-VLA objects; (2) X-ray and radio selection is an ...
On the nature of the stellar-mass black-hole candidate X
... lower energy than the electrons in the hot plasma. This means that the high-energetic electrons can give some of their energy to the soft photons. The processes are a bit different for the hard state and the soft state. In the hard state the thermal comptonization is dominant, while in the soft stat ...
... lower energy than the electrons in the hot plasma. This means that the high-energetic electrons can give some of their energy to the soft photons. The processes are a bit different for the hard state and the soft state. In the hard state the thermal comptonization is dominant, while in the soft stat ...
Chapter 14 Black Holes as Central Engines
... 14.4 Jets and Magnetic Fields A magnetic field cannot be anchored to the black hole itself because the event horizon pinches off any magnetic field lines that cross it. • However, the whirling plasma of the accretion disk lies outside the event horizon and it could have a strong magnetic field. • Th ...
... 14.4 Jets and Magnetic Fields A magnetic field cannot be anchored to the black hole itself because the event horizon pinches off any magnetic field lines that cross it. • However, the whirling plasma of the accretion disk lies outside the event horizon and it could have a strong magnetic field. • Th ...
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.