scholarly journals Pulsar Magnetic Field: Spectral Formation in Her X-1

1981 ◽  
Vol 95 ◽  
pp. 263-264
Author(s):  
J. Ventura
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Spectral Characteristics ◽  
Black Body ◽  
Frequency Range ◽  
Polar Cap ◽  
Spectral Break ◽  
Cyclotron Harmonics

The spectrum of Hercules X-1 reveals line features at 58 keV and probably at 110 keV, which have been interpreted as first and second cyclotron harmonics originating in the radiation from the hot polar cap region of a magnetic neutron star. The inferred magnetic field strength is ~ 5.3 × 1012 Gauss (Trümper et al. 1978). Other noteworthy spectral characteristics of this source are the very ‘flat’ intensity continuum in the frequency range 2 – 20 keV followed by a rather sharp spectral break near 25 keV and an intensity minimum near 40 keV. This spectrum is certainly not reminiscent of typical black-body emission. How can one understand these diverse characteristics?

scholarly journals An Emission Line in the Hard X-Ray Spectrum of Hercules X-1: Quantized Cyclotron Emission from the Neutron Star

1977 ◽  
Vol 43 ◽  
pp. 34-34
Author(s):  
W. Pietsch ◽  
C. Reppin ◽  
R. Staubert ◽  
J. Truemper ◽  
W. Voges ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Second Harmonic ◽  
Narrow Line ◽  
Electron Cyclotron Emission ◽  
Polar Cap ◽  
Astrophysical Application ◽  
X Ray ◽  
Cyclotron Emission

A four hour balloon observation of HERC X-l during the 'On-state' in the 35 day cycle was performed on May 3rd, 1976. The 1.24 second pulsations show a pulsed fraction of 58 ± 8% in the 18-31 KeV interval. A pulsed flux (1.24 sec) was discovered in the 31-88 KeV interval with a pulsed fraction of 51 ± 14%. The spectrum of the pulsed flux can be represented up to 50 KeV by an exponential distribution with KT approximately 8 KeV. At approximately 58 KeV a strong and narrow line feature occurs which we interpret as electron cyclotron emission (ΔN = 1 Landau transition) from the polar cap plasma of the rotating neutron star. The corresponding magnetic field strength is approximately 5 x 1012 Gauss, neglecting gravitational red shift. There is evidence for a second harmonic at approximately 110 KeV (ΔN = 2 ).The astrophysical application of this discovery will be discussed in some detail.

scholarly journals Determining the neutron star surface magnetic field strength of two Z sources

2012 ◽  
Vol 8 (S290) ◽  
pp. 203-204
Author(s):  
Guoqiang Ding ◽  
Chunping Huang ◽  
Yanan Wang
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Extreme Position ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Axis Of Rotation ◽  
Star Surface ◽  
Z Sources

AbstractFrom the extreme position of disk motion, we infer the neutron star (NS) surface magnetic field strength (B0) of Z-source GX 17+2 and Cyg X-2. The inferred B0 of GX 17+2 and Cyg X-2 are ~(1–5)×108 G and ~(1–3)×108 G, respectively, which are not inferior to that of millisecond X-ray pulsars or atoll sources. It is likely that the NS magnetic axis of Z sources is parallel to the axis of rotation, which could result in the lack of pulsations in these sources.

scholarly journals The Evolution of the Magnetic Fields of Neutron Stars

1992 ◽  
Vol 128 ◽  
pp. 26-34
Author(s):  
Dipankar Bhattacharya
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Theoretical Models ◽  
Radio Pulsars ◽  
Secular Evolution ◽  
History Of ◽  
Field Decay ◽  
The Magnetic Field

AbstractThe evolution of the magnetic field strength plays a major role in the life history of a neutron star. In this article the observational evidence of field evolution, in particular that of field decay and magnetic alignment, are critically examined. It is concluded that the observed decay of the spindown torque on radio pulsars cannot be caused by a secular evolution of the “obliqueness” of the neutron star, as suggested by some authors. Recent observations provide a strong indication that the decay of the magnetic field strength of a neutron star may be closely related to its evolution in a binary system. Theoretical models for such an evolution are discussed.

scholarly journals Recycling in progress: RXTE discovery of the first accretion-powered millisecond pulsar

2000 ◽  
Vol 177 ◽  
pp. 643-648
Author(s):  
M. van der Klis
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Binary System ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Radio Pulsar ◽  
Millisecond Pulsar ◽  
X Ray ◽  
Millisecond Radio

AbstractThe discovery is reported of the first accretion-powered millisecond pulsar, SAX J 1808.4–3658. This 2.5 millisecond pulsar has a magnetic field strength of 1–10108Gauss and has all the characteristics of the long-predicted millisecond radio pulsar progenitor, a neutron star in an X-ray binary system where the process of recycling is taking place at this time.

Detection of Cyclotron Lines in BL Hyi

1995 ◽  
Vol 12 (1) ◽  
pp. 81-83
Author(s):  
Lilia Ferrario ◽  
Dayal T. Wickramasinghe ◽  
Jeremy Bailey
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Wavelength Range ◽  
Near Infrared ◽  
Emission Region ◽  
Polar Cap ◽  
Spectroscopic Observations ◽  
Infrared Spectroscopic ◽  
Cyclotron Emission

AbstractWe present near-infrared spectroscopic observations over the wavelength range 0·9 to 2·5 μm of the AM Herculis system BL Hyi. During these observations, broad and resolvable cyclotron emission harmonics were visible near 1·25, 1·60 and 2·20 μm. We have interpreted these features as arising from a cyclotron emission region located near the white dwarf’s polar cap of magnetic field strength Bp = 23 MG.

Measurements on the Temperature, Dynamic Strain Amplitude and Magnetic Field Strength Dependence of the Dynamic Shear Modulus of Magnetosensitive Elastomers in a Wide Frequency Range

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Jonas Lejon ◽  
Leif Kari
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Shear Modulus ◽  
Magnetic Field Strength ◽  
Strain Amplitude ◽  
Wide Frequency Range ◽  
Dynamic Strain ◽  
Dynamic Shear Modulus ◽  
Frequency Range ◽  
Temperature Dynamic

A measurement study is conducted to investigate how changes in temperature, dynamic strain amplitude, and magnetic field strength influence the behavior of a magnetosensitive material. During the measurements seven temperatures, four magnetic fields, and three dynamic strain amplitudes are used over a 200 to 800 Hz frequency range. The results indicate a decrease in shear modulus magnitude as the dynamic strain amplitude is increased. As the frequency and magnetic field strength increases the magnitude increases. However, the measurements indicate that the temperature is the most influential of the parameters as the material stiffens significantly when the temperature reaches the transition phase. Understanding the temperature dependence increases the knowledge of magnetosensitive materials.

scholarly journals Observational constraints on the magnetic field of the bright transient Be/X-ray pulsar SXP 4.78

2019 ◽  
Vol 490 (3) ◽  
pp. 3355-3364
Author(s):  
Andrey N Semena ◽  
Alexander A Lutovinov ◽  
Ilya A Mereminskiy ◽  
Sergey S Tsygankov ◽  
Andrey E Shtykovsky ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Power Spectrum ◽  
Magnetic Field Strength ◽  
Timing Analysis ◽  
Rapid Evolution ◽  
Periodic Oscillation ◽  
X Ray ◽  
The Magnetic Field

ABSTRACT We report results of the spectral and timing analysis of the Be/X-ray pulsar SXP 4.78 using the data obtained during its recent outburst with NuSTAR, Swift, Chandra, and NICER observatories. Using an overall evolution of the system luminosity, spectral analysis, and variability power spectrum we obtain constraints on the neutron star magnetic field strength. We found a rapid evolution of the variability power spectrum during the rise of the outburst, and absence of the significant changes during the flux decay. Several low frequency quasi-periodic oscillation features are found to emerge on the different stages of the outburst, but no clear clues on their origin were found in the energy spectrum and overall flux behaviour. We use several indirect methods to estimate the magnetic field strength on the neutron star surface and found that most of them suggest magnetic field B ≲ 2 × 1012 G. The strictest upper limit comes from the absence of the cyclotron absorption features in the energy spectra and suggests relatively weak magnetic field B < 6 × 1011 G.)

scholarly journals M51 ULX-7: superorbital periodicity and constraints on the neutron star magnetic field

2019 ◽  
Vol 491 (4) ◽  
pp. 4949-4959 ◽  
Author(s):  
G Vasilopoulos ◽  
S K Lander ◽  
F Koliopanos ◽  
C D Bailyn
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Theoretical Models ◽  
Equilibrium Analysis ◽  
Free Precession ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Constant Rate

ABSTRACT In this work, we explore the applicability of standard theoretical models of accretion to the observed properties of M51 ULX-7. The spin-up rate and observed X-ray luminosity are evidence of a neutron star with a surface magnetic field of 2–7 × 1013 G, rotating near equilibrium. Analysis of the X-ray light curve of the system (Swift/XRT data) reveals the presence of a ∼39 d superorbital period. We argue that the superorbital periodicity is due to disc precession, and that material is accreted on to the neutron star at a constant rate throughout it. Moreover, by attributing this modulation to the free precession of the neutron star we estimate a surface magnetic field strength of 3–4 × 1013 G. The agreement of these two independent estimates provide strong constraints on the surface polar magnetic field strength of the NS.

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