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

scholarly journals AN ULTRA-FAST X-RAY DISK WIND IN THE NEUTRON STAR BINARY GX 340+0

2016 ◽  
Vol 822 (1) ◽  
pp. L18 ◽  
Author(s):  
J. M. Miller ◽  
J. Raymond ◽  
E. Cackett ◽  
V. Grinberg ◽  
M. Nowak
Keyword(s):  
Neutron Star ◽  
X Ray ◽  
Disk Wind ◽  
Star Binary

scholarly journals Chemical Abundances of the Secondary Stars in the Black Hole Binary A0620-00 and the Neutron Star Binary Cen X-4

2004 ◽  
Vol 194 ◽  
pp. 204-204
Author(s):  
J. I. González-Hernández ◽  
R. Rebolo ◽  
G. Israelian ◽  
J. Casares
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
High Resolution ◽  
Compact Object ◽  
Accretion Disc ◽  
Accretion Discs ◽  
Chemical Abundances ◽  
X Ray ◽  
Black Hole Binary ◽  
Star Binary

We have determined abundances in the secondary stars of the black hole X-ray binary A0620-00 and the neutron star Binary Cen X-4. These are K type stars veiled by the emission produced by the respective accretion discs. We searched for evidence of nucleosynthetic products from the progenitor of the compact object that could have contaminated the secondary stars (as in Israelian et al., 1999).Using high resolution spectra obtained with VLT/UVES, we have derived in a consistent way stellar parameters and the veiling caused by the accretion disc.

X-Ray Transients Observed with MAXI

2017 ◽  
Vol 14 (S339) ◽  
pp. 144-144
Author(s):  
N. Kawai
Keyword(s):  
Neutron Star ◽  
Space Station ◽  
X Rays ◽  
International Space ◽  
X Ray ◽  
Black Hole Binaries ◽  
Stellar Flares ◽  
Orbital Revolution ◽  
Be Star ◽  
Star Binary

AbstractMAXI (Monitor of All-sky X-ray Image) is an astronomical mission onboard the International Space Station. It started observations in August 2009. The Gas Slit Camera of MAXI is sensitive to X-rays in the energy range 2–30 keV. Most of the sky is scanned every 90 min with the orbital revolution of the ISS. With this unbiased monitoring, MAXI has detected numerous outbursts from known and unknown X-ray sources. MAXI discovered 18 X-ray novæ in seven years, including seven neutron star binaries, six black hole binaries (+candidates) and four unidentified sources. Other results include detections of superluminous stellar flares, a super-Eddington luminous flare from a white dwarf+Be Star binary near the SMC, and monitoring of recurrent outbursts from Be neutron-star binaries. Variations in X-ray-bright AGNs such as Cen A and Mrk 421 have been also monitored. This talk presented the highlights of the MAXI observations of variable sources, including the search for X-ray counterparts of gravitational-wave events.

scholarly journals Neutron Star Powered Accelerators

2000 ◽  
Vol 195 ◽  
pp. 463-471
Author(s):  
M. Ruderman
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Surrounding Medium ◽  
Radio Pulsars ◽  
X Ray ◽  
Energetic Radiation ◽  
Γ Ray ◽  
Star Binary

Neutron stars can be the underlying source of energetic particle acceleration in several ways. The huge gravitational-collapse energy released in their birth, or the violent fusion at the end of the life of a neutron-star binary, is the energy source for an accelerator in the surrounding medium far from the star. This would be the case for: (a) cosmic rays from supernova explosions with neutron-star remnants; (b) energetic radiation from “plerions” around young neutron stars (e.g., the Crab Nebula, see Pacini 2000); and (c) “afterglow” and γ-rays of cosmic Gamma-Ray Burst (GRB) sources with possible neutron-star central engines. Particles can also be energetically accelerated if a neutron star's gravitational pull sustains an accretion disk fed by a companion. Examples are accretion-powered X-ray pulsars and low-mass X-ray binaries. A third family of “neutron-star powered” accelerators consists of those which do not depend on the surrounding environment. These are the accelerators which must exist in the magnetospheres of many solitary, spinning-down, magnetized neutron stars (“spinsters”) when they are observed as radio pulsars or γ-ray pulsars. (There are probably ~ 103 dead radio pulsars for each one in our Galaxy that is still active; the ratio for γ-ray pulsars may well exceed 105.)

scholarly journals X‐Ray Emission from the Double Neutron Star Binary B1534+12: Powered by the Pulsar Wind?

2006 ◽  
Vol 646 (2) ◽  
pp. 1139-1148 ◽  
Author(s):  
O. Kargaltsev ◽  
G. G. Pavlov ◽  
G. P. Garmire
Keyword(s):  
Neutron Star ◽  
X Ray ◽  
Pulsar Wind ◽  
Star Binary

scholarly journals Interpreting GRB170817A as a giant flare from a jet-less double neutron star merger

2018 ◽  
Vol 619 ◽  
pp. A18 ◽  
Author(s):  
O. S. Salafia ◽  
G. Ghisellini ◽  
G. Ghirlanda ◽  
M. Colpi
Keyword(s):  
Neutron Star ◽  
Velocity Profile ◽  
Acceleration Process ◽  
X Ray ◽  
Emission Component ◽  
Relativistic Jet ◽  
Binary Mergers ◽  
Star Binary ◽  
Giant Flare ◽  
Prompt Emission

We show that the delay between GRB170817A and GW170817 is incompatible with de-beamed emission from an off-axis relativistic jet. The prompt emission and the subsequent radio and X-ray observations can instead be interpreted within a giant-flare-like scenario, being the result of a relativistic outflow driven by the ultra-strong magnetic field produced by magnetohydrodynamic amplification during the merger of the progenitor double neutron-star binary. Within such a picture, the data indicate that the outflow must be endowed with a steep velocity profile, with a relatively fast tail extending to Γ ∼ 8. Since the conditions for the launch of such an outflow are relatively general, and the presence of a velocity profile is a natural expectation of the acceleration process, most neutron star binary mergers should feature this quasi-isotropic, hard X-ray emission component, that could be a powerful guide to the discovery of additional kilonovae associated to relatively nearby gravitational wave events.

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.

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.

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