The radius of a neutron star - an interpretation of absorption lines from X-ray burster X1636-536

1985 ◽  
Vol 293 ◽  
pp. L19 ◽  
Author(s):  
M. Y. Fujimoto
Keyword(s):  
Neutron Star ◽  
Absorption Lines ◽  
X Ray

The magnetic field of an isolated neutron star from X-ray cyclotron absorption lines

Nature ◽  
2003 ◽  
Vol 423 (6941) ◽  
pp. 725-727 ◽  
Author(s):  
G. F. Bignami ◽  
P. A. Caraveo ◽  
A. De Luca ◽  
S. Mereghetti
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Absorption Lines ◽  
X Ray ◽  
Cyclotron Absorption ◽  
The Magnetic Field

Gravitationally redshifted absorption lines in the X-ray burst spectra of a neutron star

Nature ◽  
2002 ◽  
Vol 420 (6911) ◽  
pp. 51-54 ◽  
Author(s):  
J. Cottam ◽  
F. Paerels ◽  
M. Mendez
Keyword(s):  
Neutron Star ◽  
Absorption Lines ◽  
X Ray

scholarly journals MEASURING MAGNETIC FIELD OF NEUTRON STAR 4U 0115+63 WITH CYCLOTRON FEATURES

2013 ◽  
Vol 23 ◽  
pp. 161-164
Author(s):  
SU YAO ◽  
CHENGMIN ZHANG
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Relativistic Effect ◽  
Absorption Lines ◽  
Fundamental Feature ◽  
X Ray ◽  
Measuring Magnetic Field ◽  
Absorption Features ◽  
Main Region ◽  
Just Right

We analyze the 3-80 keV spectrum of X-ray pulsar 4U 0115+63 taken by Rossi X-ray Timing Explorer(RXTE) on April 22nd, 2008. Two absorption features at ~13.5 keV and ~20.5 keV are detected by using cyclotron scattering feature profiles to fit the spectrum, ignoring the inadequate photons of the analyzed data. The fundamental feature is just right between ~11 and ~16 keV. It seems implausible to interprete these absorption lines as cyclotron features because of their inharmonic behavior, even when relativistic effect has been taken into account. But it is possible that the main region where first harmonic line forms is slightly different from the fundamental one.

scholarly journals A persistent ultraviolet outflow from the accretion disc in a transient neutron star binary

2021 ◽  
Author(s):  
Noel Castro Segura ◽  
Christian Knigge ◽  
Knox Long ◽  
Diego Altamirano ◽  
Montserrat Armas Padilla ◽  
...  
Keyword(s):  
Neutron Star ◽  
Hubble Space Telescope ◽  
Uv Spectroscopy ◽  
Accretion Disc ◽  
Absorption Lines ◽  
Time Resolved ◽  
X Ray ◽  
Astrophysical Objects ◽  
Hard State ◽  
The Impact

Abstract All disc-accreting astrophysical objects also produce powerful disc winds and/or jets. In compact binaries containing neutron stars or black holes, accretion often takes place during violent outbursts. The main disc wind signatures seen during these eruptions are blue-shifted X-ray absorption lines. However, these signatures are only observed during "soft states", when the accretion disc generates most of the luminosity. By contrast, optical wind-formed absorption lines have recently been detected in "hard states", when the luminosity is dominated by a hot corona. The relationship between these disc wind signatures is unknown, and no erupting compact binary has so far been observed to display wind-formed lines between the X-ray and optical bands, despite the many strong resonance transitions in this ultraviolet (UV) region of the spectrum. In turn, the impact of disc winds on the overall mass and energy budget of these systems remains a key open question. Here, we show that the transient neutron star X-ray binary Swift J1858.6-0814 exhibits wind-formed, blue-shifted absorption features associated with C IV, N V and He II in time-resolved, UV spectroscopy obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope during a luminous hard state. In simultaneous ground-based observations, the optical H and He I lines also display transient blue-shifted absorption troughs. By decomposing our UV data into constant and flaring components, we demonstrate that the blue-shifted absorption is associated with the former, which implies that the outflow is always present. The joint presence of UV and optical wind features in the hard state reveals a multi-phase and/or spatially stratified evaporative outflow from the outer disc. This type of persistent mass loss across all accretion states has been predicted by radiation-hydrodynamic simulations and is required to account for the shorter-than-expected outburst durations.

A theoretical analysis of the X-ray cyclotron absorption lines of the isolated neutron star 1E1207.4-5209

2006 ◽  
Vol 30 (3) ◽  
pp. 263-273
Author(s):  
Yuan Ai-fang ◽  
Liu Dang-bo ◽  
Chen Lei ◽  
Ding Li ◽  
You Jun-hang
Keyword(s):  
Neutron Star ◽  
Theoretical Analysis ◽  
Absorption Lines ◽  
X Ray ◽  
Cyclotron Absorption

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.

scholarly journals Aperiodic Flux Variability in A 0535+262

1996 ◽  
Vol 165 ◽  
pp. 313-319
Author(s):  
Mark H. Finger ◽  
Robert B. Wilson ◽  
B. Alan Harmon ◽  
William S. Paciesas
Keyword(s):  
Neutron Star ◽  
Gamma Ray ◽  
Beat Frequency ◽  
Power Spectra ◽  
Center Frequency ◽  
X Ray ◽  
Binary Pulsar ◽  
Transient Source ◽  
Flux Variability ◽  
Burst And Transient Source

A “giant” outburst of A 0535+262, a transient X-ray binary pulsar, was observed in 1994 February and March with the Burst and Transient Source Experiment (BATSE) onboard the Compton Gamma-Ray Observatory. During the outburst power spectra of the hard X-ray flux contained a QPO-like component with a FWHM of approximately 50% of its center frequency. Over the course of the outburst the center frequency rose smoothly from 35 mHz to 70 mHz and then fell to below 40 mHz. We compare this QPO frequency with the neutron star spin-up rate, and discuss the observed correlation in terms of the beat frequency and Keplerian frequency QPO models in conjunction with the Ghosh-Lamb accretion torque model.

scholarly journals A minimal timescale for the continuum in 4U 1608-52 and Aql X-1

2021 ◽  
Vol 502 (1) ◽  
pp. L72-L78
Author(s):  
K Mohamed ◽  
E Sonbas ◽  
K S Dhuga ◽  
E Göğüş ◽  
A Tuncer ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Power Spectra ◽  
Light Curves ◽  
State Transitions ◽  
Strong Positive Correlation ◽  
Present Evidence ◽  
X Ray ◽  
X Ray Binaries ◽  
The Continuum

ABSTRACT Similar to black hole X-ray binary transients, hysteresis-like state transitions are also seen in some neutron-star X-ray binaries. Using a method based on wavelets and light curves constructed from archival Rossi X-ray Timing Explorer observations, we extract a minimal timescale over the complete range of transitions for 4U 1608-52 during the 2002 and 2007 outbursts and the 1999 and 2000 outbursts for Aql X-1. We present evidence for a strong positive correlation between this minimal timescale and a similar timescale extracted from the corresponding power spectra of these sources.

scholarly journals The study of multipeaked type-I X-ray bursts in the neutron star low-mass X-ray binary 4U 1636 − 536 with RXTE

2020 ◽  
Vol 501 (1) ◽  
pp. 168-178
Author(s):  
Chen Li ◽  
Guobao Zhang ◽  
Mariano Méndez ◽  
Jiancheng Wang ◽  
Ming Lyu
Keyword(s):  
Neutron Star ◽  
Flux Ratio ◽  
Light Curves ◽  
Type I ◽  
X Ray ◽  
Soft State ◽  
Peak Flux ◽  
Low Mass ◽  
Two Peaks ◽  
Second Peak

ABSTRACT We have found and analysed 16 multipeaked type-I bursts from the neutron-star low-mass X-ray binary 4U 1636 − 53 with the Rossi X-ray Timing Explorer (RXTE). One of the bursts is a rare quadruple-peaked burst that was not previously reported. All 16 bursts show a multipeaked structure not only in the X-ray light curves but also in the bolometric light curves. Most of the multipeaked bursts appear in observations during the transition from the hard to the soft state in the colour–colour diagram. We find an anticorrelation between the second peak flux and the separation time between two peaks. We also find that in the double-peaked bursts the peak-flux ratio and the temperature of the thermal component in the pre-burst spectra are correlated. This indicates that the double-peaked structure in the light curve of the bursts may be affected by enhanced accretion rate in the disc, or increased temperature of the neutron star.

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