Multi-Wavelength Observations of Known, and Searches
... Meurs & van den Heuvel (1989) predicted ~30 such systems in the Galaxy in this brief phase. ...
... Meurs & van den Heuvel (1989) predicted ~30 such systems in the Galaxy in this brief phase. ...
Instruments and Methods of Astrophysical X-ray
... From Bragg/Thomson to Photoelectric The turning point of X-Ray Astronomy was the launch of Einstein satellite that first introduced the X-ray Optics. The dramatic increase in sensitivity for the detection of faint sources and the capability to resolve extended source with imaging detectors in the f ...
... From Bragg/Thomson to Photoelectric The turning point of X-Ray Astronomy was the launch of Einstein satellite that first introduced the X-ray Optics. The dramatic increase in sensitivity for the detection of faint sources and the capability to resolve extended source with imaging detectors in the f ...
Ion-supported tori: a thermal bremsstrahlung model for the X
... emerged in relation to recent discussions of energy advection solutions (see Begelman 1978 and Abramowicz et al. 1988, for high-M, optically thick systems, and Rees et al. 1982; Abramowicz et al. 1995 and Narayan & Yi 1994, 1995a, b for the low-M, optically thin solution relevant here) for accretion ...
... emerged in relation to recent discussions of energy advection solutions (see Begelman 1978 and Abramowicz et al. 1988, for high-M, optically thick systems, and Rees et al. 1982; Abramowicz et al. 1995 and Narayan & Yi 1994, 1995a, b for the low-M, optically thin solution relevant here) for accretion ...
First young loose association in the northern hemisphere?
... !!Taking account this property, Guillout et al. (1999) cross-correlated the ROSAT All-Sky Survey (RASS) with the Tycho catalogue creating the largest ("14 000 active stars) and most comprehensive set of late-type stellar X-ray sources, the so-called RasTyc sample. This stellar population can be used ...
... !!Taking account this property, Guillout et al. (1999) cross-correlated the ROSAT All-Sky Survey (RASS) with the Tycho catalogue creating the largest ("14 000 active stars) and most comprehensive set of late-type stellar X-ray sources, the so-called RasTyc sample. This stellar population can be used ...
Lecture 2. Isolated Neutron Stars – I.
... The satellite was launched on December 12, 1970. The program was ended in March 1973. The other name SAS-1 2-20 keV The first full sky survey. 339 sources. ...
... The satellite was launched on December 12, 1970. The program was ended in March 1973. The other name SAS-1 2-20 keV The first full sky survey. 339 sources. ...
Turning over a new leaf
... their background radio and X-ray emission4 (Fig. 1). The relationship also holds for flares over many orders of magnitude5, from socalled nanoflares on the Sun to stellar superflares. To understand this relationship we have to know a little bit about how both types of radiation are created. Cool sta ...
... their background radio and X-ray emission4 (Fig. 1). The relationship also holds for flares over many orders of magnitude5, from socalled nanoflares on the Sun to stellar superflares. To understand this relationship we have to know a little bit about how both types of radiation are created. Cool sta ...
MICROQUASARS - Osservatorio Astronomico di Roma-INAF
... DIFFICULT TO FOLLOW AND TO FIND mblazars from HMXBs may appear as variable gamma-ray sources due to Inverse Compton on UV photons of donor (Romero, Kauffman, Mirabel 2002; Bosch-Ramon & Paredes, 2004) ...
... DIFFICULT TO FOLLOW AND TO FIND mblazars from HMXBs may appear as variable gamma-ray sources due to Inverse Compton on UV photons of donor (Romero, Kauffman, Mirabel 2002; Bosch-Ramon & Paredes, 2004) ...
contributed talk in splinter session
... present at this radius. Such a large amount of angular momentum must come from further out in the disk in the form of a disk wind. An accretion powered stellar wind on the other hand carries away the angular momentum imparted to the star by the accretion process. Its effectiveness (relative to a dis ...
... present at this radius. Such a large amount of angular momentum must come from further out in the disk in the form of a disk wind. An accretion powered stellar wind on the other hand carries away the angular momentum imparted to the star by the accretion process. Its effectiveness (relative to a dis ...
A Tale of Two (Solar) Telescopes: something old, something
... deals with the two bottom-most rungs of Drake’s Ladder, where sadly the sexiness is low, but on positive side the knowledge content was though to be high; even so, a few surprises still were to be found… ...
... deals with the two bottom-most rungs of Drake’s Ladder, where sadly the sexiness is low, but on positive side the knowledge content was though to be high; even so, a few surprises still were to be found… ...
Broad Relativistic Iron Lines from Neutron Star LMXBs
... the extreme world of a Low-mass X-ray binary (LMXB) Equipotential surfaces in a binary system ...
... the extreme world of a Low-mass X-ray binary (LMXB) Equipotential surfaces in a binary system ...
the chandra deep field–north survey. xvii. evolution of
... the temperatures show that a wide range of spectral models can be fitted to the data. In a few cases, additional spectral components that are not statistically significant may be present (see the notes to Table 3). 2.3. X-Ray Variability Since the arrival time for each X-ray event is recorded to wit ...
... the temperatures show that a wide range of spectral models can be fitted to the data. In a few cases, additional spectral components that are not statistically significant may be present (see the notes to Table 3). 2.3. X-Ray Variability Since the arrival time for each X-ray event is recorded to wit ...
Summary - X-ray Astronomy Group at ISAS
... • Suitable algebraic superposition- just the right number of objects, evolving the right way with redshift, with the right distribution of column densities can produce the volume emissivity, log N-log S and the x-ray spectrum. • Such models are remarkably ...
... • Suitable algebraic superposition- just the right number of objects, evolving the right way with redshift, with the right distribution of column densities can produce the volume emissivity, log N-log S and the x-ray spectrum. • Such models are remarkably ...
PHY418 Particle Astrophysics
... following several years of observations by Vela defence satellites • these were designed to ...
... following several years of observations by Vela defence satellites • these were designed to ...
Nature paper - University of Southampton
... binaries, contains neutron stars that accrete material from a more massive companion star5. The two subpopulations are most probably associated with the two distinct types of neutron-starforming supernova, with electron-capture supernovae preferentially producing systems with short spin periods, sho ...
... binaries, contains neutron stars that accrete material from a more massive companion star5. The two subpopulations are most probably associated with the two distinct types of neutron-starforming supernova, with electron-capture supernovae preferentially producing systems with short spin periods, sho ...
Superconducting Detectors: Sensitivity Over Ten Orders of Magnitude
... Is a particular nation violating nuclear treaties? Can we account for all of their plutonium? Do we know what it is being used for? Gamma-ray spectroscopy What is this defect in my semiconductor wafer? How can I fix it? Soft x-ray spectroscopy (now commercial!) Do we understand the electron structur ...
... Is a particular nation violating nuclear treaties? Can we account for all of their plutonium? Do we know what it is being used for? Gamma-ray spectroscopy What is this defect in my semiconductor wafer? How can I fix it? Soft x-ray spectroscopy (now commercial!) Do we understand the electron structur ...
X-ray and UV Transients
... >10 events y-1 even if the sensitivity is 102 less. • The observed signals have UV flux~host, so confusion with (even mildly) variable sources is an issue unless additional information is available • A combined UV survey+optical SN survey like PTF will be powerful to get retrospective measurements ...
... >10 events y-1 even if the sensitivity is 102 less. • The observed signals have UV flux~host, so confusion with (even mildly) variable sources is an issue unless additional information is available • A combined UV survey+optical SN survey like PTF will be powerful to get retrospective measurements ...
Clusters of Galaxies
... or centrally dominant galaxy (Morgan and Osterbrock 1969) which is very seldom, if ever found outside of clusters. " • There were also an unusual type of radio source found primarily in clusters, a so-called WAT, or wide angle tailed source (Owen and Rudnick 1976) . " • first indications of cluste ...
... or centrally dominant galaxy (Morgan and Osterbrock 1969) which is very seldom, if ever found outside of clusters. " • There were also an unusual type of radio source found primarily in clusters, a so-called WAT, or wide angle tailed source (Owen and Rudnick 1976) . " • first indications of cluste ...
Measuring the Masses of Neutron Stars
... spiral-in likely results in the removal of the envelope of the Be companion, and after the (second) supernova a bound (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M ...
... spiral-in likely results in the removal of the envelope of the Be companion, and after the (second) supernova a bound (or disrupted) double neutron star remains, like the Hulse-Taylor binary pulsar PSR 1913+16 (or a neutron star – white dwarf system, if the mass of the Be companion is less than 8 M ...
VLT identifications in the Chandra/XMM
... ratios (HR > 0), with (absorbed) luminosities in the range 1041–44 erg s–1. Direct spectral fits of the XMM-Newton and (some) Chandra spectra clearly indicate that these harder spectra are due to neutral gas absorption and not due to a flatter intrinsic slope (see Mainieri et al., 2002). Therefore t ...
... ratios (HR > 0), with (absorbed) luminosities in the range 1041–44 erg s–1. Direct spectral fits of the XMM-Newton and (some) Chandra spectra clearly indicate that these harder spectra are due to neutral gas absorption and not due to a flatter intrinsic slope (see Mainieri et al., 2002). Therefore t ...
The Milky Way
... Some neutron stars have magnetic fields ~ 1000 times stronger even than normal neutron stars. These care called Magnetars. ...
... Some neutron stars have magnetic fields ~ 1000 times stronger even than normal neutron stars. These care called Magnetars. ...
HEA_Pulsars_2002
... spinning motion (P usually < 1sec, dP/dt>0) • Pulsating X-ray sources / X-ray pulsators compact objects (generally neutron stars) in binary systems. Accrete matter from normal star companion. (P ~ 10s secs, dP/dt<0) ...
... spinning motion (P usually < 1sec, dP/dt>0) • Pulsating X-ray sources / X-ray pulsators compact objects (generally neutron stars) in binary systems. Accrete matter from normal star companion. (P ~ 10s secs, dP/dt<0) ...
The X-ray Bursters Problem and its Implications to the Equation of
... unstable and lead to thermonuclear ashes. This would be caused by unstable burning of a several meters thick layer of accreted hydrogen and helium on the surface of neutron stars from the binary companion. The group noted that the energy of these ashes could produce variable X-ray emission from th ...
... unstable and lead to thermonuclear ashes. This would be caused by unstable burning of a several meters thick layer of accreted hydrogen and helium on the surface of neutron stars from the binary companion. The group noted that the energy of these ashes could produce variable X-ray emission from th ...
Pulsars
... • Pulsating X-ray sources / X-ray pulsators - compact objects (generally neutron stars) in binary systems Accrete matter from normal star companion (P ~ 10s, dP/dt < 0) ...
... • Pulsating X-ray sources / X-ray pulsators - compact objects (generally neutron stars) in binary systems Accrete matter from normal star companion (P ~ 10s, dP/dt < 0) ...
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.