scholarly journals The thermal-radiative wind in the neutron star low-mass X-ray binary GX 13 + 1

2020 ◽  
Vol 497 (4) ◽  
pp. 4970-4980
Author(s):  
Ryota Tomaru ◽  
Chris Done ◽  
Ken Ohsuga ◽  
Hirokazu Odaka ◽  
Tadayuki Takahashi
Keyword(s):  
Neutron Star ◽  
Velocity Structure ◽  
Isotropic Turbulence ◽  
Azimuthal Velocity ◽  
High Energy ◽  
Absorption Lines ◽  
X Ray ◽  
Transmission Grating ◽  
Star Binary ◽  
Spectrometer Data

ABSTRACT We fit the observed high-ionization X-ray absorption lines in the neutron star binary GX13 + 1 with a full simulation of a thermal-radiative wind. This uses a radiation hydrodynamic code coupled to Monte Carlo radiation transfer to compute the observed line profiles from hydrogen and helium-like iron and nickel, including all strong K α and K β transitions. The wind is very strong as this object has a very large disc and is very luminous. The absorption lines from Fe K α are strongly saturated as the ion columns are large, so the line equivalent widths depend sensitively on the velocity structure. We additionally simulate the lines including isotropic turbulence at the level of the azimuthal and radial velocities. We fit these models to the Fe xxv and xxvi absorption lines seen in the highest resolution Chandra third-order high-energy transmission grating spectrometer data. These data already rule out the addition of turbulence at the level of the radial velocity of ∼500 km s−1. The velocity structure predicted by the thermal-radiative wind alone is a fairly good match to the observed profile, with an upper limit to additional turbulence at the level of the azimuthal velocity of ∼100 km s−1. This gives stringent constraints on any remaining contribution from magnetic acceleration.

The young Be-star binary Circinus X-1

2018 ◽  
Vol 14 (S346) ◽  
pp. 125-130
Author(s):  
Norbert S. Schulz ◽  
Timothy E. Kallman ◽  
Sebastian Heinz ◽  
Paul Sell ◽  
Peter Jonker ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Emission Line ◽  
High Energy ◽  
X Ray ◽  
Transmission Grating ◽  
Grating Spectrometer ◽  
Be Star ◽  
Star Binary ◽  
Moderate Magnetic Field

AbstractCir X-1 is a young X-ray binary exhibiting X-ray flux changes of four orders of magnitude over several decades. It has been observed many times since the launch of the Chandra X-ray Observatory with high energy transmission grating spectrometer and each time the source gave us a vastly different look. At its very lowest X-ray flux we found a single 1.7 keV blackbody spectrum with an emission radius of 0.5 km. Since the neutron star in Cir X-1 is only few thousand years old we identify this as emission from an accretion column since at this youth the neutron star is assumed to be highly magnetized. At an X-ray flux of 1.8×10−11 erg cm−2 s−1 this implies a moderate magnetic field of a few times of 1011 G. The photoionized X-ray emission line properties at this low flux are consistent with B5-type companion wind. We suggest that Cir X-1 is a very young Be-star binary.

Discovery of Narrow X-Ray Absorption Lines from NGC 3783 with the [ITAL]Chandra[/ITAL] High Energy Transmission Grating Spectrometer

2000 ◽  
Vol 535 (1) ◽  
pp. L17-L20 ◽  
Author(s):  
Shai Kaspi ◽  
W. N. Brandt ◽  
Hagai Netzer ◽  
Rita Sambruna ◽  
George Chartas ◽  
...  
Keyword(s):  
High Energy ◽  
Absorption Lines ◽  
Energy Transmission ◽  
X Ray ◽  
Transmission Grating ◽  
Grating Spectrometer ◽  
X Ray Absorption

The [ITAL]Chandra[/ITAL] High-Energy Transmission Grating Observation of an X-Ray Ionization Cone in Markarian 3

2000 ◽  
Vol 543 (2) ◽  
pp. L115-L118 ◽  
Author(s):  
Masao Sako ◽  
Steven M. Kahn ◽  
Frits Paerels ◽  
Duane A. Liedahl
Keyword(s):  
High Energy ◽  
Energy Transmission ◽  
X Ray ◽  
Transmission Grating

scholarly journals ORBITAL VARIATION OF THE X-RAY EMISSION FROM THE DOUBLE NEUTRON STAR BINARY J1537+1155

2011 ◽  
Vol 741 (1) ◽  
pp. 65 ◽  
Author(s):  
Martin Durant ◽  
Oleg Kargaltsev ◽  
Igor Volkov ◽  
George G. Pavlov
Keyword(s):  
Neutron Star ◽  
X Ray ◽  
Star Binary ◽  
Orbital Variation

High-resolution x-ray studies of an AXAF high-energy transmission grating

1994 ◽  
Author(s):  
Salim Abdali ◽  
Finn E. Christensen ◽  
Herbert W. Schnopper ◽  
Thomas H. Markert ◽  
Daniel Dewey ◽  
...  
Keyword(s):  
High Resolution ◽  
High Energy ◽  
Energy Transmission ◽  
X Ray ◽  
Transmission Grating

scholarly journals The Nature of the Compact Object in the Hard X-Ray Source 4U2206+54

2004 ◽  
Vol 194 ◽  
pp. 208-208
Author(s):  
J. M. Torrejón ◽  
I. Kreykenbohni ◽  
A. Orr ◽  
L. Titarchuk ◽  
I. Negueruela
Keyword(s):  
Neutron Star ◽  
Accretion Disk ◽  
Compact Object ◽  
High Energy ◽  
Energy Data ◽  
X Ray ◽  
Hot Plasma ◽  
Cyclotron Line ◽  
First Time

We present an analysis of archival RXTE and BeppoSAX data of the X-ray source 4U2206+54. For the first time, high energy data (≥ 30 keV) is analyzed. The data is well described by comptonization models in which seed photons with temperatures between 1.1 keV arid 1.5 keV are comptonized by a hot plasma at 50 keV thereby producing a hard tail which extends up to 100 keV. From luminosity arguments it is shown that the area of the soft photons source must be small (r ≈ 1 km) and that the presence of an accretion disk in this system is unlikely. Here we report on the possible existence of a cyclotron line around 30 keV . The presence of a neutron star in the system is strongly favored by the available data.

scholarly journals Multiwavelength campaign on Mrk 509

2019 ◽  
Vol 623 ◽  
pp. A82 ◽  
Author(s):  
G. A. Kriss ◽  
N. Arav ◽  
D. Edmonds ◽  
J. Ely ◽  
J. S. Kaastra ◽  
...  
Keyword(s):  
High Energy ◽  
Resolving Power ◽  
Host Galaxy ◽  
Active Nucleus ◽  
X Ray ◽  
Transmission Grating ◽  
Outflow Rate ◽  
Mass Outflow ◽  
Far Ultraviolet ◽  
The Impact

Aims. To elucidate the location, physical conditions, mass outflow rate, and kinetic luminosity of the outflow from the active nucleus of the Seyfert 1 galaxy Mrk 509, we used coordinated UV and X-ray spectral observations in 2012 to follow up our lengthier campaign conducted in 2009. Methods. We observed Mrk 509 with the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) on 2012-09-03 and 2012-10-11 coordinated with X-ray observations using the High Energy Transmission Grating on the Chandra X-ray Observatory. Our far-ultraviolet spectra used grating G140L on COS to cover wavelengths from 920–2000 Å at a resolving power of ∼2000, and gratings G130M and G160M to cover 1160–1750 Å at a resolving power of ∼15, 000. Results. We detect variability in the blueshifted UV absorption lines on timescales spanning 3–12 years. The inferred densities in the absorbing gas are greater than log n cm−3 ∼ 3. For ionization parameters ranging over log U = −1.5 to −0.2, we constrain the distances of the absorbers to be closer than 220 pc to the active nucleus. Conclusions. The impact on the host galaxy appears to be confined to the nuclear region.

scholarly journals Towards mapping turbulence in the intra-cluster medium

2019 ◽  
Vol 629 ◽  
pp. A143 ◽  
Author(s):  
Nicolas Clerc ◽  
Edoardo Cucchetti ◽  
Etienne Pointecouteau ◽  
Philippe Peille
Keyword(s):  
Monte Carlo ◽  
Structure Function ◽  
Velocity Structure ◽  
High Energy ◽  
Sample Variance ◽  
Physical Parameters ◽  
Sample Mean ◽  
X Ray ◽  
Spatially Resolved ◽  
Mean And Variance

Context. X-ray observations of galaxy clusters provide insights into the nature of gaseous turbulent motions, their physical scales, and the fundamental processes to which they are related. Spatially-resolved, high-resolution spectral measurements of X-ray emission lines provide diagnostics on the nature of turbulent motions in emitting atmospheres. Since they are acting on scales comparable to the size of the objects, the uncertainty on these physical parameters is limited by the number of observational measurements, through sample variance. Aims. We propose a different and complementary approach to repeating numerical simulations for the computation of sample variance (i.e. Monte-Carlo sampling) by introducing new analytical developments for lines diagnosis. Methods. We considered the model of a “turbulent gas cloud”, consisting in isotropic and uniform turbulence described by a universal Kolmogorov power-spectrum with random amplitudes and phases in an optically thin medium. Following a simple prescription for the four-term correlation of Fourier coefficients, we derived generic expressions for the sample mean and variance of line centroid shift, line broadening, and projected velocity structure function. We performed a numerical validation based on Monte-Carlo simulations for two popular models of gas emissivity based on the β-model. Results. Generic expressions for the sample variance of line centroid shifts and broadening in arbitrary apertures are derived and match the simulations within their range of applicability. Generic expressions for the mean and variance of the structure function are provided and verified against simulations. An application to the Athena/X-IFU (Advanced Telescope for High-ENergy Astrophysics/X-ray Integral Field Unit) and XRISM/Resolve (X-ray Imaging and Spectroscopy Mission) instruments forecasts the potential of sensitive, spatially-resolved spectroscopy to probe the inertial range of turbulent velocity cascades in a Coma-like galaxy cluster. Conclusions. The formulas provided are of generic relevance and can be implemented in forecasts for upcoming or current X-ray instrumentation and observing programmes.

scholarly journals Accretion heated atmospheres of X-ray bursting neutron stars

2018 ◽  
Vol 619 ◽  
pp. A114 ◽  
Author(s):  
V. F. Suleimanov ◽  
J. Poutanen ◽  
K. Werner
Keyword(s):  
Neutron Star ◽  
Model Atmosphere ◽  
High Energy ◽  
Energy Dissipation Rate ◽  
Chemical Compositions ◽  
Type I ◽  
Coulomb Interactions ◽  
Spectral Evolution ◽  
X Ray ◽  
High Energy Tail

Some thermonuclear (type I) X-ray bursts at the neutron star surfaces in low-mass X-ray binaries take place during hard persistent states of the systems. Spectral evolution of these bursts is well described by the atmosphere model of a passively cooling neutron star when the burst luminosity is high enough. The observed spectral evolution deviates from the model predictions when the burst luminosity drops below a critical value of 20–70% of the maximum luminosity. The amplitude of the deviations and the critical luminosity correlate with the persistent luminosity, which leads us to suggest that these deviations are induced by the additional heating of the accreted particles. We present a method for computation of the neutron star atmosphere models heated by accreted particles assuming that their energy is released via Coulomb interactions with electrons. We computed the temperature structures and the emergent spectra of the atmospheres of various chemical compositions and investigate the dependence of the results on the velocity of accreted particles, their temperature and the penetration angle. We show that the heated atmosphere develops two different regions. The upper one is the hot (20–100 keV) corona-like surface layer cooled by Compton scattering, and the deeper, almost isothermal optically thick region with a temperature of a few keV. The emergent spectra correspondingly have two components: a blackbody with the temperature close to that of the isothermal region and a hard Comptonized component (a power law with an exponential decay). Their relative contribution depends on the ratio of the energy dissipation rate of the accreted particles to the intrinsic flux from the neutron star surface. These spectra deviate strongly from those of undisturbed, passively cooling neutron star atmospheres, with the main differences being the presence of a high-energy tail and a strong excess in the low-energy part of the spectrum. They also lack the iron absorption edge, which is visible in the spectra of undisturbed low-luminosity atmospheres with solar chemical composition. Using the computed spectra, we obtained the dependences of the dilution and color-correction factors as functions of relative luminosities for pure helium and solar abundance atmospheres. We show that the helium model atmosphere heated by accretion corresponding to 5% of the Eddington luminosity describes well the late stages of the X-ray bursts in 4U 1820−30.

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