Measuring the Masses of Neutron Stars
... dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion which will become a Thorne-Zytkow object, a red supergiant with a high mass loss rate. These objects have been predicte ...
... dwarf system, if the mass of the Be companion is less than 8 M A). In HMXBs with an orbital period less than about a year the compact object will enter the core of the OB companion which will become a Thorne-Zytkow object, a red supergiant with a high mass loss rate. These objects have been predicte ...
Stellar Evolution
... Observed brightness combined with large distance implies huge energy output of GRBs, if they are emitting isotropically: E ~ 1054 erg L ~ 1051 erg/s ...
... Observed brightness combined with large distance implies huge energy output of GRBs, if they are emitting isotropically: E ~ 1054 erg L ~ 1051 erg/s ...
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 ...
High-Time Resolution Astrophysics (HTRA) in FP7
... limits of these devices and motivate the development of new products. ● HTRA is strong in Europe which is the home of the ULTRACAM, OPTIMA and STJ fast photometers. ● HTRA-enabled instruments can promote access as many EU countries without direct access to 4m+ telescopes have HTRA communities. ...
... limits of these devices and motivate the development of new products. ● HTRA is strong in Europe which is the home of the ULTRACAM, OPTIMA and STJ fast photometers. ● HTRA-enabled instruments can promote access as many EU countries without direct access to 4m+ telescopes have HTRA communities. ...
Altair -- the ``hottest`` magnetically active star in X-rays
... Fig. 1 we show the count rate in the 0.2–2.0 keV band as measured by the EPIC, i.e. summed PN and MOS, instrument in time-steps of half an hour. While clearly no strong flares are present, significant variability of Altair’s X-ray brightness at a level of roughly 30% on timescales of hours is seen i ...
... Fig. 1 we show the count rate in the 0.2–2.0 keV band as measured by the EPIC, i.e. summed PN and MOS, instrument in time-steps of half an hour. While clearly no strong flares are present, significant variability of Altair’s X-ray brightness at a level of roughly 30% on timescales of hours is seen i ...
1. INTRODUCTION
... as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do not display rotationally modulated light curves and that can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only o ...
... as these stars often show several distinct stochastic events. We have focused our analysis on young, active stars that do not display rotationally modulated light curves and that can be considered as single X-ray sources. Some stars in the sample are detected or known binary systems, in which only o ...
Massive stars as thermonuclear reactors and their explosions
... sial (see e.g. the discussion in [96]). It is possible that the identification of the key aspects in the explosion may require seminal observations about the conditions in the supernova core other than the indirect evidence such as explosion asymmetries, pulsar kicks or nucleosynthetic yields. Such ...
... sial (see e.g. the discussion in [96]). It is possible that the identification of the key aspects in the explosion may require seminal observations about the conditions in the supernova core other than the indirect evidence such as explosion asymmetries, pulsar kicks or nucleosynthetic yields. Such ...
The impact of surface temperature inhomogeneities on quiescent
... observed in accreting systems in outburst. However, this calculation has not been performed specifically for hydrogen atmosphere models (which experience greater limb darkening) at temperatures relevant to quiescent NS low-mass X-ray binaries. Second, given constraints on pulsed flux from a given qu ...
... observed in accreting systems in outburst. However, this calculation has not been performed specifically for hydrogen atmosphere models (which experience greater limb darkening) at temperatures relevant to quiescent NS low-mass X-ray binaries. Second, given constraints on pulsed flux from a given qu ...
Ultraluminous X-ray Sources in Andromeda Galaxy
... Proportional Counter instrument (FWHM ∼ 1’) on Einstein, it was difficult to separate these sources from the nucleus of galaxies. These observations lead to various speculations about the nature of these X-ray sources e.g. AGNs with a low accretion rate, a massive stellar mass black hole accreting a ...
... Proportional Counter instrument (FWHM ∼ 1’) on Einstein, it was difficult to separate these sources from the nucleus of galaxies. These observations lead to various speculations about the nature of these X-ray sources e.g. AGNs with a low accretion rate, a massive stellar mass black hole accreting a ...
X-Ray Properties of Young Stars and Stellar Clusters
... most powerful flares seen in the contemporary Sun; the implied fluence of energetic particles may be 105× above solar levels (Feigelson et al., 2002). The Orion solar analogs emit a relatively constant “characteristic” X-ray level about three-fourths of the time (see Fig. 1). The X-ray spectrum of t ...
... most powerful flares seen in the contemporary Sun; the implied fluence of energetic particles may be 105× above solar levels (Feigelson et al., 2002). The Orion solar analogs emit a relatively constant “characteristic” X-ray level about three-fourths of the time (see Fig. 1). The X-ray spectrum of t ...
Spatial resolution and field of view, sensitivity
... • BRDF is bi-reflectance distribution function. It gives scattered amplitude as a function of input and output angle. ...
... • BRDF is bi-reflectance distribution function. It gives scattered amplitude as a function of input and output angle. ...
Jul y 10-12,
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
CONSTRAINTS ON THE VERY HIGH ENERGY
... constraints on the diffuse cosmic background at infraredyoptical wavelengths. Despite considerable uncertainty in this background, we find that robust constraints may still be placed on the integrated emissivity of potential VHE sources in the universe. The limits are tighter than those obtained by ...
... constraints on the diffuse cosmic background at infraredyoptical wavelengths. Despite considerable uncertainty in this background, we find that robust constraints may still be placed on the integrated emissivity of potential VHE sources in the universe. The limits are tighter than those obtained by ...
Lecture 9: Radiation processes Almost all astronomical information
... When spectral features are not numerous, we can detect the continuum between them and obtain a reasonably accurate value for the star’s effective surface temperature. The line blanketing alters the atmosphere’s blackbody character. Spectrophotometry: the Spectral Energy Distribution (SED) ...
... When spectral features are not numerous, we can detect the continuum between them and obtain a reasonably accurate value for the star’s effective surface temperature. The line blanketing alters the atmosphere’s blackbody character. Spectrophotometry: the Spectral Energy Distribution (SED) ...
Document
... It is used to obtain images of conductive surfaces at an atomic scale 2 × 10−10 m or 0.2 nanometre. It can also be used to alter the observed material by manipulating individual atoms, triggering chemical reactions, and creating ions by removing individual electrons from atoms and then reverting the ...
... It is used to obtain images of conductive surfaces at an atomic scale 2 × 10−10 m or 0.2 nanometre. It can also be used to alter the observed material by manipulating individual atoms, triggering chemical reactions, and creating ions by removing individual electrons from atoms and then reverting the ...
LIFE ON A PLANET ORBITING THE ALPHA CENTAURI STAR
... for carbon-based life. For both of these sections, we used the Earth-Sun star system as a guide because it successfully supports carbon-based life. Combining these calculations we came up with a potential elliptical orbit for such a planet between the stars Alpha Centauri A and B. A planet in this e ...
... for carbon-based life. For both of these sections, we used the Earth-Sun star system as a guide because it successfully supports carbon-based life. Combining these calculations we came up with a potential elliptical orbit for such a planet between the stars Alpha Centauri A and B. A planet in this e ...
Definition of a Twelve-Point Polygonal SAA boundary for the GLAST
... consists of 89 plastic scintillating tiles for the purpose of vetoing charged particles. These tiles are sensitive to cosmic rays, but not gamma rays. Cosmic rays vastly outnumber gamma rays. ...
... consists of 89 plastic scintillating tiles for the purpose of vetoing charged particles. These tiles are sensitive to cosmic rays, but not gamma rays. Cosmic rays vastly outnumber gamma rays. ...
An extended X-ray object ejected from the PSR B1259
... K+14 pointed out, the fast, steady motion over such a large period of time poses a number of problems. If the ejected clump consists solely of synchrotron-emitting relativistic electrons or positrons, possibly confined by the magnetic field, it should decelerate very quickly by the drag force (assum ...
... K+14 pointed out, the fast, steady motion over such a large period of time poses a number of problems. If the ejected clump consists solely of synchrotron-emitting relativistic electrons or positrons, possibly confined by the magnetic field, it should decelerate very quickly by the drag force (assum ...
UHM-A-736-2013-1-detector
... photographs of the Sun by Foucault and Fizeau • Sunspots photographed in 1858 by W. De La Rue • Jansen and Lockyer in the 1870s photographed the solar spectrum and discovered the spectral lines of Helium. • Ainsee Common photographed Orion Nebula and these revealed stars and details you could not se ...
... photographs of the Sun by Foucault and Fizeau • Sunspots photographed in 1858 by W. De La Rue • Jansen and Lockyer in the 1870s photographed the solar spectrum and discovered the spectral lines of Helium. • Ainsee Common photographed Orion Nebula and these revealed stars and details you could not se ...
Point Spread Function of real Wolter-I X-ray mirrors
... where α is the grazing incidence angle of X-rays, should be classified as roughness. Fourier components exceeding this limit should instead contribute to the geometric errors. Although reasonable, this criterion can apparently be applied only to a discrete power spectrum. In addition, it seems more l ...
... where α is the grazing incidence angle of X-rays, should be classified as roughness. Fourier components exceeding this limit should instead contribute to the geometric errors. Although reasonable, this criterion can apparently be applied only to a discrete power spectrum. In addition, it seems more l ...
IXO as an observatory in the large telescopes era
... The current deepest surveys with Chandra reach great depths at the central aim point. These have yielded a handful of AGN candidates at z>5 (Luo et al 2010), but none is yet confirmed at z>6. To harvest significant samples of moderate luminosity AGN at z=7-10, however, we need to reach this kind of ...
... The current deepest surveys with Chandra reach great depths at the central aim point. These have yielded a handful of AGN candidates at z>5 (Luo et al 2010), but none is yet confirmed at z>6. To harvest significant samples of moderate luminosity AGN at z=7-10, however, we need to reach this kind of ...
in the milky way - Chandra X
... chandra explores “ downtown” in the milky way The word galaxy comes from the Greek word meaning “milky circle” or, more familiarly, “milky way.” The white band of light across the night sky that we call the Milky Way was poetically described long before Galileo. But with his small telescope, what he ...
... chandra explores “ downtown” in the milky way The word galaxy comes from the Greek word meaning “milky circle” or, more familiarly, “milky way.” The white band of light across the night sky that we call the Milky Way was poetically described long before Galileo. But with his small telescope, what he ...
Magnetars: properties, origin and evolution
... also emit intermediate and giant flares, the latter involving the release of up to about 1046 erg in less than half a second. Magnetars also show pulsed X-ray emission with typical luminosity of ∼ 1035 erg s−1 in persistent sources, and ranging from ∼ 1032 to 1036 erg s−1 in transient ones. The puls ...
... also emit intermediate and giant flares, the latter involving the release of up to about 1046 erg in less than half a second. Magnetars also show pulsed X-ray emission with typical luminosity of ∼ 1035 erg s−1 in persistent sources, and ranging from ∼ 1032 to 1036 erg s−1 in transient ones. The puls ...
Astronomy
... Unit 1 Early Astronomy Notes 1. Early astronomers identified celestial objects with _________ and ___________. 2. List five phenomena that early astronomers linked to celestial changes. ...
... Unit 1 Early Astronomy Notes 1. Early astronomers identified celestial objects with _________ and ___________. 2. List five phenomena that early astronomers linked to celestial changes. ...
The presence of gamma rays in space was known before they were
... however the main definition of a gamma ray is that its source has to be from the nucleus of an atom and not from one of the electrons surrounding the nucleus. This means X-rays which are generated from electrons can have same energies as gamma rays, but it is important to make a distinction between ...
... however the main definition of a gamma ray is that its source has to be from the nucleus of an atom and not from one of the electrons surrounding the nucleus. This means X-rays which are generated from electrons can have same energies as gamma rays, but it is important to make a distinction between ...
X-ray astronomy detector
X-ray astronomy detectors are instruments that detect X-rays for use in the study of X-ray astronomy.X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray emission from celestial objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. X-ray astronomy is part of space science.X-ray astronomy detectors have been designed and configured primarily for energy and occasionally for wavelength detection using a variety of techniques usually limited to the technology of the time.