part 2
... The X-ray study of rotation-powered or radio pulsars has had a close link with Xray astronomy from its very beginning. After the discovery of Sco X−1 as the first extra-solar X-ray source by rocket-borne Geiger counters (Giacconi et al. 1962), the next source of celestial X-rays identified was the C ...
... The X-ray study of rotation-powered or radio pulsars has had a close link with Xray astronomy from its very beginning. After the discovery of Sco X−1 as the first extra-solar X-ray source by rocket-borne Geiger counters (Giacconi et al. 1962), the next source of celestial X-rays identified was the C ...
Astronomy Astrophysics The accretion environment in Vela X-1 during a flaring period using
... Observations of the system during the eclipse of the X-ray pulsar with Tenma, ASCA, and Chandra have revealed various fluorescent lines in addition to highly ionized lines and radiative recombination continua that imply the existence of optically thick and clumped matter in addition to warm ionized ...
... Observations of the system during the eclipse of the X-ray pulsar with Tenma, ASCA, and Chandra have revealed various fluorescent lines in addition to highly ionized lines and radiative recombination continua that imply the existence of optically thick and clumped matter in addition to warm ionized ...
The XXL Survey - I. Scientific motivations − XMM
... Context. The quest for the cosmological parameters that describe our universe continues to motivate the scientific community to undertake very large survey initiatives across the electromagnetic spectrum. Over the past two decades, the Chandra and XMM-Newton observatories have supported numerous stu ...
... Context. The quest for the cosmological parameters that describe our universe continues to motivate the scientific community to undertake very large survey initiatives across the electromagnetic spectrum. Over the past two decades, the Chandra and XMM-Newton observatories have supported numerous stu ...
X-ray astronomy of stellar coronae (Review)
... with data from previous rocket flights, our modern picture of the solar and therefore stellar coronae. The solar X-ray corona is now understood as a dynamic ensemble of magnetic loops that contain hot plasma in ever-changing constellations, yet always related to the underlying photospheric magnetic ...
... with data from previous rocket flights, our modern picture of the solar and therefore stellar coronae. The solar X-ray corona is now understood as a dynamic ensemble of magnetic loops that contain hot plasma in ever-changing constellations, yet always related to the underlying photospheric magnetic ...
Explosive sources of the highest energy radiation
... During this period the average >100 MeV flux nova explosion reported by Chinese astronoof the system was 0.9 × 10 –10 erg cm –2 s –1. What mers in AD 1054. At the heart of the nebula is was completely unexpected was that 30 days a pulsar that loses rotational energy through a after periastron passag ...
... During this period the average >100 MeV flux nova explosion reported by Chinese astronoof the system was 0.9 × 10 –10 erg cm –2 s –1. What mers in AD 1054. At the heart of the nebula is was completely unexpected was that 30 days a pulsar that loses rotational energy through a after periastron passag ...
Gamma-ray burst investigation via polarimetry and spectroscopy
... present-day measurement capabilities in the optical/NIR as well as X-rays are not adequate to determine the density of local matter around GRBs. However, at γ -rays this matter will be measurable through nuclear resonance absorption even though this matter is simultaneously being ionized: the GRB ga ...
... present-day measurement capabilities in the optical/NIR as well as X-rays are not adequate to determine the density of local matter around GRBs. However, at γ -rays this matter will be measurable through nuclear resonance absorption even though this matter is simultaneously being ionized: the GRB ga ...
LOCALIZATION AND OBSERVATIONS OF GRB010921 BY THE …
... Epeak is the peak of the F spectrum E is the collimation-corrected GRB energy: E = (1 – cos j ) E,iso Underlying physical reason is not known, but the radiation process (and photon energy) should be related to the energy content The correlation makes GRBs important cosmological tools, because ...
... Epeak is the peak of the F spectrum E is the collimation-corrected GRB energy: E = (1 – cos j ) E,iso Underlying physical reason is not known, but the radiation process (and photon energy) should be related to the energy content The correlation makes GRBs important cosmological tools, because ...
Telescopes - UMass Astronomy
... smears images over several arc-seconds ⇒ seeing Best sites: 0.5-1 arc second Atmospheric seeing limits the angular resolution of ground-based optical telescopes Solutions: 1. Put telescope in Earth orbit (hard, $$$) 2. Adaptively bend mirror to compensate for atmospheric motions (hard, $$$) ...
... smears images over several arc-seconds ⇒ seeing Best sites: 0.5-1 arc second Atmospheric seeing limits the angular resolution of ground-based optical telescopes Solutions: 1. Put telescope in Earth orbit (hard, $$$) 2. Adaptively bend mirror to compensate for atmospheric motions (hard, $$$) ...
Vicky Kaspi Chandra Anomalous X-ray Pulsars Fotis Gavriil
... • Young, isolated, ultrahighly magnetized neutron stars • Soft Gamma Repeaters and Anomalous X-ray Pulsars • X-ray pulsars with periods 2-12 s, large spin-down rates, moderate Lx, soft X-ray spectra typically fit by blackbody+power law ...
... • Young, isolated, ultrahighly magnetized neutron stars • Soft Gamma Repeaters and Anomalous X-ray Pulsars • X-ray pulsars with periods 2-12 s, large spin-down rates, moderate Lx, soft X-ray spectra typically fit by blackbody+power law ...
English version - Richard de Grijs
... “The tails seem to tell us why that is,” said Posselt, adding that the pulsars’ spin and magnetic axis orientations influence what kind of emission is seen on Earth. Geminga may have magnetic poles quite close to the top and bottom of the object, and nearly aligned spin poles, much like Earth. On ...
... “The tails seem to tell us why that is,” said Posselt, adding that the pulsars’ spin and magnetic axis orientations influence what kind of emission is seen on Earth. Geminga may have magnetic poles quite close to the top and bottom of the object, and nearly aligned spin poles, much like Earth. On ...
Document
... Summary of Solar Flares • Magnetic loops become entangled by motions of the footprints, storing magnetic energy • This energy is released through rapid magnetic reconnection that accelerates particles. • Flares emit in all wavelength regimes. • The general theory is well-established, but the detail ...
... Summary of Solar Flares • Magnetic loops become entangled by motions of the footprints, storing magnetic energy • This energy is released through rapid magnetic reconnection that accelerates particles. • Flares emit in all wavelength regimes. • The general theory is well-established, but the detail ...
Matter under extreme conditions experiments at the Linac
... high-energy density physics regime. This instrument combines the world’s brightest x-ray source, the LCLS x-ray beam, with high-power lasers consisting of two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These lasers produce short-lived states of matter with high pressures, ...
... high-energy density physics regime. This instrument combines the world’s brightest x-ray source, the LCLS x-ray beam, with high-power lasers consisting of two nanosecond Nd:glass laser beams and one short-pulse Ti:sapphire laser. These lasers produce short-lived states of matter with high pressures, ...
A Study of the Nature and Representative Features of Supernova
... (Galactic) supernovae remnants exist, with a few dozen other heavily suspected. For a listing and summary see Green D.A. 2001. The remainder of this paper will focus on Galactic SNRs since they are the most accessible and easiest to study. The first extragalactic supernova was not observed until 188 ...
... (Galactic) supernovae remnants exist, with a few dozen other heavily suspected. For a listing and summary see Green D.A. 2001. The remainder of this paper will focus on Galactic SNRs since they are the most accessible and easiest to study. The first extragalactic supernova was not observed until 188 ...
3011800000810
... times are given in Table 1. For the first two observations, when the source was detectable and imaged on-axis, we extracted source spectra from each detector using an extraction radius of r ¼ 18 00 ; we used r ¼ 30 00 in the third observation when IGR J163584726 was imaged offaxis. We then built in ...
... times are given in Table 1. For the first two observations, when the source was detectable and imaged on-axis, we extracted source spectra from each detector using an extraction radius of r ¼ 18 00 ; we used r ¼ 30 00 in the third observation when IGR J163584726 was imaged offaxis. We then built in ...
doctoral thesis (Dissertation)
... are required to explain the observed spectrum. For a electron density > 105 cm−3 all shock dimensions are so small that they remain undetectable in optical observations as observed. The spectral resolution in X-rays is not sufficient to analyse the line profiles, so UV data is used for this purpose. ...
... are required to explain the observed spectrum. For a electron density > 105 cm−3 all shock dimensions are so small that they remain undetectable in optical observations as observed. The spectral resolution in X-rays is not sufficient to analyse the line profiles, so UV data is used for this purpose. ...
(2004) - H. Peter
... higher “filling-factor” than Sun? not enough space on the surface and: also stellar X-rays are structured stellar corona are not only brighter, they have also high densities high temperatures ...
... higher “filling-factor” than Sun? not enough space on the surface and: also stellar X-rays are structured stellar corona are not only brighter, they have also high densities high temperatures ...
Swift and NuSTAR observations of XTE J1859+083
... or solid state, a neutron star with a characteristic size of R ≈ 10 km and a mass between 1.44 and 3 M . Core masses above 3 M lead to the same supernova mechanism but leave a black hole instead of a NS. The rapid decrease of the radius leads to extreme conditions. Because of angular momentum con ...
... or solid state, a neutron star with a characteristic size of R ≈ 10 km and a mass between 1.44 and 3 M . Core masses above 3 M lead to the same supernova mechanism but leave a black hole instead of a NS. The rapid decrease of the radius leads to extreme conditions. Because of angular momentum con ...
Radio observations of the 13hXMM–Newton/ROSAT Deep X
... problems which led to power outages at some of the antennae, correlator problems and high interference. The remaining 14 h of good data were calibrated and mapped in the standard fashion with AIPS. However, heavy cleaning and careful positioning of CLEAN boxes were not sufficient to remove fully the ...
... problems which led to power outages at some of the antennae, correlator problems and high interference. The remaining 14 h of good data were calibrated and mapped in the standard fashion with AIPS. However, heavy cleaning and careful positioning of CLEAN boxes were not sufficient to remove fully the ...
A wide Chandra view of the core of the Perseus cluster
... New large-scale Chandra data on the core of the Perseus cluster, A 426, are presented here. They follow our earlier 900 ks ACIS-S image which covered a 8x8 arcmin region centred on the nucleus of the dominant galaxy NGC 1275 (Fabian et al 2000; Fabian et al 2006; Sanders & Fabian 2007). That image, ...
... New large-scale Chandra data on the core of the Perseus cluster, A 426, are presented here. They follow our earlier 900 ks ACIS-S image which covered a 8x8 arcmin region centred on the nucleus of the dominant galaxy NGC 1275 (Fabian et al 2000; Fabian et al 2006; Sanders & Fabian 2007). That image, ...
ROSAT Ian R. Stevens* and David K. Strickland*
... We note that the detection of a broad He II l4686 feature can be difficult even with high signal-to-noise ratio (S/N) data. This does mean that our sample of WR galaxies will tend to be rather heterogenous. Future studies will have to focus on broader samples of starburst galaxies and starburst regi ...
... We note that the detection of a broad He II l4686 feature can be difficult even with high signal-to-noise ratio (S/N) data. This does mean that our sample of WR galaxies will tend to be rather heterogenous. Future studies will have to focus on broader samples of starburst galaxies and starburst regi ...
models for low-mass x-ray binaries in the elliptical
... 1037 ergs s1), pointing to a different LMXB formation mechanism in GCs. The natural question that arises is whether (1) all LMXBs were formed in GCs through dynamical interactions and some eventually escaped or some GCs dissolved in the field, or (2) field LMXBs were born in situ through binary evo ...
... 1037 ergs s1), pointing to a different LMXB formation mechanism in GCs. The natural question that arises is whether (1) all LMXBs were formed in GCs through dynamical interactions and some eventually escaped or some GCs dissolved in the field, or (2) field LMXBs were born in situ through binary evo ...
CEA
... Peak energy flux in the 4-25 keV band is 1/3 of 50-300 keV Peak photon flux is ~4 times higher in the 4-25 keV ...
... Peak energy flux in the 4-25 keV band is 1/3 of 50-300 keV Peak photon flux is ~4 times higher in the 4-25 keV ...
A FUSE Survey of Coronal Forbidden Lines in Late
... We searched for evidence of coronal forbidden lines in the 900–1200 Å region in our sample of stellar spectra. Because of our relatively poor knowledge of the rest wavelengths of these lines, the relatively weak signal of the coronal lines, and the moderate likelihood of coincidental blends with lo ...
... We searched for evidence of coronal forbidden lines in the 900–1200 Å region in our sample of stellar spectra. Because of our relatively poor knowledge of the rest wavelengths of these lines, the relatively weak signal of the coronal lines, and the moderate likelihood of coincidental blends with lo ...
Multiwavelength properties of γ-ray loud binary systems.
... Variability of emission from the Galactic Plane is due to the presence of compact γ-ray sources. The only firmly established class of generically variable Galactic sources is that of -ray-loud binaries. In this respect, it is not surprising that the highest excess variability is found in the directi ...
... Variability of emission from the Galactic Plane is due to the presence of compact γ-ray sources. The only firmly established class of generically variable Galactic sources is that of -ray-loud binaries. In this respect, it is not surprising that the highest excess variability is found in the directi ...
Absorption of high-energy gamma rays in Cygnus X-3
... the system. We provide in Sect. 2 and in Appendix A a complete study of the absorption of GeV photons in the radiation field of an accretion disk. Long-term observations in X-rays revealed that Cygnus X-3 presents complex spectral and temporal features. Szostek et al. (2008) classified the X-ray spe ...
... the system. We provide in Sect. 2 and in Appendix A a complete study of the absorption of GeV photons in the radiation field of an accretion disk. Long-term observations in X-rays revealed that Cygnus X-3 presents complex spectral and temporal features. Szostek et al. (2008) classified the X-ray spe ...
X-ray astronomy
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical 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 the space science related to a type of space telescope that can see farther than standard light-absorption telescopes, such as the Mauna Kea Observatories, via x-ray radiation.X-ray emission is expected from astronomical objects that contain extremely hot gasses at temperatures from about a million kelvin (K) to hundreds of millions of kelvin (MK). Although X-rays have been observed emanating from the Sun since the 1940s, the discovery in 1962 of the first cosmic X-ray source was a surprise. This source is called Scorpius X-1 (Sco X-1), the first X-ray source found in the constellation Scorpius. The X-ray emission of Scorpius X-1 is 10,000 times greater than its visual emission, whereas that of the Sun is about a million times less. In addition, the energy output in X-rays is 100,000 times greater than the total emission of the Sun in all wavelengths. Based on discoveries in this new field of X-ray astronomy, starting with Scorpius X-1, Riccardo Giacconi received the Nobel Prize in Physics in 2002. It is now known that such X-ray sources as Sco X-1 are compact stars, such as neutron stars or black holes. Material falling into a black hole may emit X-rays, but the black hole itself does not. The energy source for the X-ray emission is gravity. Infalling gas and dust is heated by the strong gravitational fields of these and other celestial objects.Many thousands of X-ray sources are known. In addition, the space between galaxies in galaxy clusters is filled with a very hot, but very dilute gas at a temperature between 10 and 100 megakelvins (MK). The total amount of hot gas is five to ten times the total mass in the visible galaxies.