Super-Eddington outburst in a binary system: V4641 Sgr Mikhail Revnivtsev, Marat Gilfanov
... • In order to get rid of extreme luminosity it is enough to get rid of assumption of large optical depth in UV – the emitted spectrum is not black body • Therefore – the emitting region is neither accretion disk nor star ...
... • In order to get rid of extreme luminosity it is enough to get rid of assumption of large optical depth in UV – the emitted spectrum is not black body • Therefore – the emitting region is neither accretion disk nor star ...
Neutron Stars - Lick Observatory
... distance is estimated by parallax at only 200 light years. From its black body spectrum, a surface temperature of half a million Kelvin is found, and from its flux a radius of order 10 km is inferred. Circumstantial evidence indicates that it was born in a supernova explosion a million years ago. Su ...
... distance is estimated by parallax at only 200 light years. From its black body spectrum, a surface temperature of half a million Kelvin is found, and from its flux a radius of order 10 km is inferred. Circumstantial evidence indicates that it was born in a supernova explosion a million years ago. Su ...
MHD seismology as a tool to diagnose the coronae of X
... and particle acceleration in the reconnection region as per the analogy of the occurrence of solar flares (e.g., see the reviews by Benz 2008; Shibata & Magara 2011, and references cited therein). Particles are accelerated downwards into the chromosphere to heat the denser ambient plasma, which furt ...
... and particle acceleration in the reconnection region as per the analogy of the occurrence of solar flares (e.g., see the reviews by Benz 2008; Shibata & Magara 2011, and references cited therein). Particles are accelerated downwards into the chromosphere to heat the denser ambient plasma, which furt ...
3011800000810
... within 3 of the mean rate. The remaining useful exposure 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 observati ...
... within 3 of the mean rate. The remaining useful exposure 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 observati ...
Article PDF - IOPscience
... 2145 Sheridan Road, Evanston, IL 60208, USA Received 2015 January 12; accepted 2015 February 26; published 2015 March 19 ...
... 2145 Sheridan Road, Evanston, IL 60208, USA Received 2015 January 12; accepted 2015 February 26; published 2015 March 19 ...
High energy processes in young stellar objects and high-mass X
... 4.2 Fermi observational data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Fermi /LAT data analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Discussion . . . . . . . . . . . . . . . ...
... 4.2 Fermi observational data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Fermi /LAT data analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Discussion . . . . . . . . . . . . . . . ...
An extended X-ray object ejected from the PSR B1259
... setup was similar to our previous observations that have been analyzed in K+14. The target was imaged on the front-illuminated ACIS-I3 chip in timed exposure mode, the data were telemetered in ‘very faint’ format. A 1/8 subarray was used to reduce the frame time to 0.4 s and mitigate the effect of p ...
... setup was similar to our previous observations that have been analyzed in K+14. The target was imaged on the front-illuminated ACIS-I3 chip in timed exposure mode, the data were telemetered in ‘very faint’ format. A 1/8 subarray was used to reduce the frame time to 0.4 s and mitigate the effect of p ...
X-ray Binaries
... M Roche-lobe filling companions are sometimes referred to as Intermediate Mass X-ray Binaries (IMXBs). For a comprehensive review on X-ray binaries we refer to ...
... M Roche-lobe filling companions are sometimes referred to as Intermediate Mass X-ray Binaries (IMXBs). For a comprehensive review on X-ray binaries we refer to ...
systems - Research in Astronomy and Astrophysics
... (2001). Numerous X-ray flares have been observed since then by both Chandra and XMM-Newton. Their variability time scales, including temporal structure on several-minute time scales during the flares, indicate that they arise much closer to the black hole than the quiescent emission, probably within ...
... (2001). Numerous X-ray flares have been observed since then by both Chandra and XMM-Newton. Their variability time scales, including temporal structure on several-minute time scales during the flares, indicate that they arise much closer to the black hole than the quiescent emission, probably within ...
GRB 130603B: No Compelling Evidence for Neutron Star Merger
... The near infrared (NIR) flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB) 130603B measured with the Hubble Space Telescope (HST) and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron star merger origin of SHBs. However, the X-ray afterglo ...
... The near infrared (NIR) flare/rebrightening in the afterglow of the short hard gamma ray burst (SHB) 130603B measured with the Hubble Space Telescope (HST) and an alleged late-time X-ray excess were interpreted as possible evidence of a neutron star merger origin of SHBs. However, the X-ray afterglo ...
Chandra News The Secret X-ray Lives of Planetary Nebulae
... were of the compact PN BD +30°3639, and this object has also been the subject of the deepest Chandra observations of any PN (a total of ∼400 ks in Cycles 1, 6, and 10). Both imaging and gratings (LETG) spectroscopy have been performed, with ACIS-S as the sensor (Kastner et al. 2000; Yu et al. 2009). ...
... were of the compact PN BD +30°3639, and this object has also been the subject of the deepest Chandra observations of any PN (a total of ∼400 ks in Cycles 1, 6, and 10). Both imaging and gratings (LETG) spectroscopy have been performed, with ACIS-S as the sensor (Kastner et al. 2000; Yu et al. 2009). ...
PDF only - at www.arxiv.org.
... adopting very shallow incidence angles (0.1 ÷ 0.4 deg) and graded multilayer coatings5,6. For example, the SIMBOL-X sensitivity band is 0.5 ÷ 80 keV, with a required angular resolution of 15 ÷ 20 arcsec. Other X-ray observatories will instead take the advantage of a very large Field of View (1.5 deg ...
... adopting very shallow incidence angles (0.1 ÷ 0.4 deg) and graded multilayer coatings5,6. For example, the SIMBOL-X sensitivity band is 0.5 ÷ 80 keV, with a required angular resolution of 15 ÷ 20 arcsec. Other X-ray observatories will instead take the advantage of a very large Field of View (1.5 deg ...
microquasars
... -THE PHYSICS OF RELATIVISTIC JETS FROM BH’s -THE CONNECTION BETWEEN ACCRETION & EJECTION -THE FORMATION OF BLACK HOLES AND NEUTRON STARS: Can stars of >40 Msolar end as neutron stars rather than BHs ? Do BHs of >10 Msolar form promptly rather than in bright SN ? ...
... -THE PHYSICS OF RELATIVISTIC JETS FROM BH’s -THE CONNECTION BETWEEN ACCRETION & EJECTION -THE FORMATION OF BLACK HOLES AND NEUTRON STARS: Can stars of >40 Msolar end as neutron stars rather than BHs ? Do BHs of >10 Msolar form promptly rather than in bright SN ? ...
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 ...
An exceptionally bright flare from SGR 1806–20 and the origins of
... dissipation of magnetic energy. Here we report the detection of a long (380 s) giant flare from SGR 1806–20, which was much more luminous than any previous transient event observed in our Galaxy. (In the first 0.2 s, the flare released as much energy as the Sun radiates in a quarter of a million yea ...
... dissipation of magnetic energy. Here we report the detection of a long (380 s) giant flare from SGR 1806–20, which was much more luminous than any previous transient event observed in our Galaxy. (In the first 0.2 s, the flare released as much energy as the Sun radiates in a quarter of a million yea ...
X-ray telescopes
... of 1.2 m. The angular resolution is specified at the sub-arcsecond level. Since the discovery of the first non-solar x-ray source only 22 years have passed during which x-ray astronomy has grown to a mature astronomical research discipline. This fact is related to the ability to successfully build a ...
... of 1.2 m. The angular resolution is specified at the sub-arcsecond level. Since the discovery of the first non-solar x-ray source only 22 years have passed during which x-ray astronomy has grown to a mature astronomical research discipline. This fact is related to the ability to successfully build a ...
Extraordinary Luminous Soft X-Ray Transient MAXI
... Red, green, and blue color maps represent the intensities in 2–4, 4–10, and 10–20 keV bands, respectively. Grid lines are drawn every 1 hr and 10◦ in longitude and latitude, respectively. (b) Scan image of GSC-H around Ttrig . The source and background regions for the spectral analysis are shown in ...
... Red, green, and blue color maps represent the intensities in 2–4, 4–10, and 10–20 keV bands, respectively. Grid lines are drawn every 1 hr and 10◦ in longitude and latitude, respectively. (b) Scan image of GSC-H around Ttrig . The source and background regions for the spectral analysis are shown in ...
NGC 6231: a young open cluster under X-rays
... • The canonical relation is tightly constrained V but still not understood on firm theoretical ground ! • Our sample is inhomogeneous in terms of spectral sub-type and luminosity class same mechanism for all • Confirmed by a recent study by Anthokin et al. on Cyg OB2 • Very limited room for the B ...
... • The canonical relation is tightly constrained V but still not understood on firm theoretical ground ! • Our sample is inhomogeneous in terms of spectral sub-type and luminosity class same mechanism for all • Confirmed by a recent study by Anthokin et al. on Cyg OB2 • Very limited room for the B ...
Present Carbon and Oxygen data with efficiency numbers
... The Constellation-X mission will provide an instrument with large effective collecting area and high spectral resolution relative to past and current x-ray observatories. An overview of the mission and science goals is given by Tananbaum, et al.1, and can be found on the web at http://constellation. ...
... The Constellation-X mission will provide an instrument with large effective collecting area and high spectral resolution relative to past and current x-ray observatories. An overview of the mission and science goals is given by Tananbaum, et al.1, and can be found on the web at http://constellation. ...
Radio-loud ROSAT sources near the North Ecliptic Pole
... Dept. of Physics, Bucknell University, Lewisburg, PA 17837, U.S.A. Fermi National Accelerator Laboratory, Batavia, IL 60510, U.S.A. Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802, U.S.A. E.O. Hulburt Center for Space Research, Naval Research Laboratory, ...
... Dept. of Physics, Bucknell University, Lewisburg, PA 17837, U.S.A. Fermi National Accelerator Laboratory, Batavia, IL 60510, U.S.A. Dept. of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802, U.S.A. E.O. Hulburt Center for Space Research, Naval Research Laboratory, ...
Comparison between the luminosity functions of X
... 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 not show absorption in their individual spectra. However, their stac ...
... 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 not show absorption in their individual spectra. However, their stac ...
Cool Stars in the Galaxy — A ROSAT and ASCA View.
... lution instruments on Skylab (Reeves 1976, Vaiana et al. 1973) showed the solar corona to be composed of complex loop structures associated with underlying photospheric and chromospheric features, in particular magnetic field structures. Also in the 1970’s, the detection of X-ray quiescent and flari ...
... lution instruments on Skylab (Reeves 1976, Vaiana et al. 1973) showed the solar corona to be composed of complex loop structures associated with underlying photospheric and chromospheric features, in particular magnetic field structures. Also in the 1970’s, the detection of X-ray quiescent and flari ...
Demonstration of multilayer reflective optics at photon energies
... The specular reflectivity data at 0.51 MeV and 0.65 MeV are shown in Figure 3. The reflectivity was modeled using the IDL software package IMD [23]. IMD implements the Fresnel equations, including Névot-Croce factors to account for interface imperfections. Additional custom software was written to ...
... The specular reflectivity data at 0.51 MeV and 0.65 MeV are shown in Figure 3. The reflectivity was modeled using the IDL software package IMD [23]. IMD implements the Fresnel equations, including Névot-Croce factors to account for interface imperfections. Additional custom software was written to ...
The Local Bubble
... function of direction and partly of distance. This is what we illusdirectly compared here with the measured background. trate here, in a simplified manner, using only the X-ray surface Found that both sources are required to produce 0.25This keV brightness. work will be updated and improved as highe ...
... function of direction and partly of distance. This is what we illusdirectly compared here with the measured background. trate here, in a simplified manner, using only the X-ray surface Found that both sources are required to produce 0.25This keV brightness. work will be updated and improved as highe ...
History of X-ray astronomy
The history of X-ray astronomy begins in the 1920s, with interest in short wave communications for the U.S. Navy. This was soon followed by extensive study of the earth's ionosphere. By 1927, interest in the detection of X-ray and ultraviolet (UV) radiation at high altitudes inspired researchers to launch Goddard's rockets into the upper atmosphere to support theoretical studies and data gathering. The first successful rocket flight equipped with instrumentation able to detect solar ultraviolet radiation occurred in 1946. X-ray solar studies began in 1949. By 1973 a solar instrument package orbited on Skylab providing significant solar data.In 1965 the Goddard Space Flight Center program in X-ray astronomy was initiated with a series of balloon-borne experiments. In the 1970s this was followed by high altitude sounding rocket experiments, and that was followed by orbiting (satellite) observatories.The first rocket flight to successfully detect a cosmic source of X-ray emission was launched in 1962 by a group at American Science and Engineering (AS&E).X-ray wavelengths reveal information about the bodies (sources) that emit them.