scholarly journals Breaking the 100 MG Barrier: The First High Field Magnetic CV

1997 ◽  
Vol 163 ◽  
pp. 409-412
Author(s):  
Paula Szkody ◽  
Gary D. Schmidt ◽  
Paul S. Smith ◽  
Andrew Silber ◽  
D.W. Hoard ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
White Dwarf ◽  
High Field ◽  
Optical Spectra ◽  
Cataclysmic Variable ◽  
High State ◽  
Optical Photometry ◽  
X Ray ◽  
Cyclotron Emission

AbstractWe present results from IUE and optical spectra, optical photometry and circular polarimetry during high and low states of the highly luminous soft X-ray cataclysmic variable AR UMa that identifies the primary in this system as a white dwarf with a magnetic field of 230 MG. The high magnetic field likely threads accretion blobs all the way from the secondary to below the surface of the white dwarf, resulting in a lack of polarised cyclotron emission and an extreme soft-X-ray luminosity during the high state.

SPIN PERIODICITY MEASUREMENTS OF WHITE DWARFS HOSTED IN SOUTHERN HARD X–RAY INTERMEDIATE POLAR CANDIDATES

2010 ◽  
Vol 19 (06) ◽  
pp. 797-803
Author(s):  
ILEANA ANDRUCHOW ◽  
NICOLA MASETTI ◽  
DOMITILLA DE MARTINO ◽  
SERGIO A. CELLONE ◽  
ELENA MASON ◽  
...  
Keyword(s):  
Optical Spectroscopy ◽  
White Dwarf ◽  
Preliminary Analysis ◽  
Cataclysmic Variables ◽  
Optical Spectra ◽  
X Rays ◽  
Optical Photometry ◽  
X Ray ◽  
Orbital Periods ◽  
Magnetic Cataclysmic Variables

Thanks to the combination of hard X–ray data afforded with the INTEGRAL satellite and optical spectroscopy at various telescopes, a number of new, possibly magnetic, Cataclysmic Variables (CVs) has been recently discovered. We here report on the preliminary analysis of B-band optical photometry performed with the 2.15m "Jorge Sahade" telescope at CASLEO (Argentina) on 5 CVs discovered at hard X–rays with INTEGRAL and which show features of a magnetic white dwarf (WD) in their optical spectra. The aim of these observations is to derive the orbital periods of these systems and the spin periodicity of their accreting WD.

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 High Field X-ray Diffraction Study on a Magnetic-Field-Induced Valence Transition in YbInCu4

2006 ◽  
Vol 75 (2) ◽  
pp. 024710 ◽  
Author(s):  
Y. H. Matsuda ◽  
T. Inami ◽  
K. Ohwada ◽  
Y. Murata ◽  
H. Nojiri ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Diffraction Study ◽  
High Field ◽  
X Ray Diffraction ◽  
Valence Transition ◽  
X Ray

scholarly journals The Intermediate Polars

1983 ◽  
Vol 72 ◽  
pp. 155-172
Author(s):  
Brian Warner
Keyword(s):  
Magnetic Fields ◽  
White Dwarf ◽  
Variable Star ◽  
Theoretical Models ◽  
Cataclysmic Variable ◽  
General Role ◽  
X Ray ◽  
Low Mass ◽  
Intermediate Polars ◽  
X Ray Binaries

Until 1976, cataclysmic variable star research proceeded with few requirements for the inclusion of magnetic fields in theoretical models. Although models for low-mass X-ray binaries stressed the importance of magnetic fields (Lamb et at. 1973) and there was an increasing number of known magnetic single white dwarfs (Angel 1977), and a magnetised white dwarf had been one of the models proposed to explain the rapid oscillations in DQ Her (Herbst et al. 1974, Katz 1975), there was no anticipation of the more general role that magnetic fields now seem destined to play. The two major reviews of the time (Robinson 1976, Warner 1976) scarcely considered the presence of magnetic fields.

scholarly journals A magnetic white dwarf with five H α components

2019 ◽  
Vol 489 (3) ◽  
pp. 3648-3654 ◽  
Author(s):  
Mukremin Kilic ◽  
B Rolland ◽  
P Bergeron ◽  
Z Vanderbosch ◽  
P Benni ◽  
...  
Keyword(s):  
Magnetic Field ◽  
White Dwarf ◽  
White Dwarfs ◽  
Surface Composition ◽  
Degenerate System ◽  
Inhomogeneous Surface ◽  
Optical Photometry ◽  
Photometric Variability ◽  
Rotational Modulation ◽  
Complex Magnetic Field

ABSTRACT G183−35 is an unusual white dwarf that shows an H α line split into five components, instead of the usual three components seen in strongly magnetic white dwarfs. Potential explanations for the unusual set of lines include a double degenerate system containing two magnetic white dwarfs and/or rotational modulation of a complex magnetic field structure. Here, we present time-resolved spectroscopy of G183−35 obtained at the Gemini Observatory. These data reveal two sets of absorption lines that appear and disappear over a period of about 4 h. We also detect low-level (0.2 per cent) variability in optical photometry at the same period. We demonstrate that the spectroscopic and photometric variability can be explained by the presence of spots on the surface of the white dwarf and a change in the average field strength from about 4.6 to 6.2 MG. The observed variability is clearly due to G183−35’s relatively short spin period. However, rotational modulation of a complex magnetic field by itself cannot explain the changes seen in the central H α component. An additional source of variability in the line profiles, most likely due to a chemically inhomogeneous surface composition, is also needed. We propose further observations of similar objects to test this scenario.

Structure Control of Hydroxyapatite Using a Magnetic Field

2007 ◽  
Vol 561-565 ◽  
pp. 1565-1568 ◽  
Author(s):  
Kazuhiko Iwai ◽  
Jun Akiyama ◽  
Shigeo Asai
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Slip Casting ◽  
Casting Process ◽  
Ceramic Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Control ◽  
Crystal Alignment ◽  
The Magnetic Field

A high magnetic field is a useful tool to control the crystal alignment of ceramic materials. In this study, a horizontal 10T static magnetic field was imposed on slurry containing hydroxyapatite (HAp) crystals under the horizontal mold rotation during slip casting process so as to introduce uni-axial alignment for some amount of crystals in the sample, and then it was sintered in atmosphere without the magnetic field. From X-ray diffraction, it has been found that the HAp crystals in the sample treated with the mold rotation under the magnetic field were aligned its c-axis to a particular direction.

An X-ray View of the High Magnetic Field Radio Pulsar J1119–6127: Any Link to Magnetars?

2008 ◽  
Author(s):  
Samar Safi-Harb ◽  
C. Bassa ◽  
Z. Wang ◽  
A. Cumming ◽  
V. M. Kaspi
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Radio Pulsar ◽  
X Ray

scholarly journals Strong Magnetic Fields in Nova Systems

1990 ◽  
Vol 122 ◽  
pp. 47-47
Author(s):  
H.S. Stockman ◽  
G.D. Schmidt
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Circular Polarization ◽  
Magnetic Moment ◽  
White Dwarf ◽  
Strong Magnetic Fields ◽  
General Picture ◽  
Cyclotron Emission ◽  
Accretion Shock ◽  
Independent Confirmation

The discovery of variable circular polarization in V1500 Cygni (the remnant of Nova Cygni 1975) is the strongest evidence for the presence of highly magnetic white dwarfs in nova systems. If interpreted in terms of diluted cyclotron emission from a hot accretion shock, the recent observations of Schmidt and Stockman (1990 preprint, Ap. J. 1991) of the color dependence of the circular polarization can provide a empirical lower-limit to the primary’s magnetic field strength of B > 25 × 106 gauss. Such a field strength is comparable to those observed in other magnetic variables, thus providing support for the general picture of the current and pre-nova system and the explanation for the observed search-light and period changes following the eruption. Schmidt and Stockman have also measured lengthening of the polarimetric period indicating that the system will be resynchronized within a few centuries and well before the next nova eruption. This is an independent confirmation of a significant magnetic moment for the white dwarf primary.

High-field liquid state NMR hyperpolarization: a combined DNP/NMRD approach

2014 ◽  
Vol 16 (35) ◽  
pp. 18781-18787 ◽  
Author(s):  
Petr Neugebauer ◽  
Jan G. Krummenacker ◽  
Vasyl P. Denysenkov ◽  
Christina Helmling ◽  
Claudio Luchinat ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Dynamic Nuclear Polarization ◽  
Liquid State ◽  
High Field ◽  
Nuclear Polarization ◽  
Nmr Relaxation ◽  
Relaxation Dispersion ◽  
Liquid Solutions ◽  
High Fields

Dynamic nuclear polarization and NMR relaxation dispersion measurements have been performed on liquid solutions of TEMPOL radicals in solvents with different viscosities at a high magnetic field of 9.2 T. The results indicate that fast dynamics significantly contribute to DNP enhancements at high fields.

Sign in / Sign up

Export Citation Format

Share Document