Magnetism in white dwarfs
White dwarf stars broadband circular polarization and normal/quadratic Zeeman effect
Engineering topics
Publications and source records attributed to Angel, J. R. P..
White dwarf stars broadband circular polarization and normal/quadratic Zeeman effect
Poor energy resolution and the steeply varying continuum spectrum make it impossible to obtain with proportional counters an unambiguous identification of certain emission features of Sco X-1. For this reason a Bragg crystal spectrometer was constructed. The instrument, flown successfully aboard an Aerobee-170 rocket, scanned the spectral range from 2.4 to 2.9 keV. The spectrometer consists of two large reflecting crystals of synthetic graphite. The results obtained during the flight of the instrument clearly indicate that the Bragg method can yield much higher sensitivity to line emission than can proportional counter methods.
Rocket studies of the low-energy X-ray sky conducted so far suffer from serious experimental problems. Therefore, an apparatus was design ed to overcome the outstanding experimental problems. The instrument developed was successfully flown in an Aerobee-170 rocket. The new device utilizes a grazing incidence paraboloid as an energy concentrator and low-pass filter. The effective bandpass of the instrument from 100 to 280 eV is determined by the combination of the counter window transmission and the mirror reflectivity.
The polarizer is briefly described. The polarization of the whole pulse is not significantly different from zero (-0.15 plus or minus 0.70 per cent). Polarization measurements of the leading edge and trailing edge of the main pulse are also given.
White dwarf stars continuum circular polarization as function of time and wavelength, emphasizing magnetic star search
White dwarf star circular polarized light, indicating strong magnetic field
Magnetic fields of DA dwarfs observed with photoelectric polarimeter, noting no fields observable
Bragg reflecting crystals for spectroscopy and polarimetry in X ray astronomy
Taurus X-1 X ray emission polarization, using rocket-borne polarimeter
X ray line emission from Sco X-1 using Monte Carlo estimates of spectral distribution of scattered photons in terms of Fe line and cosmic abundance
Polarization of nonspherical plasma emission region in thermal X ray stars
X ray polarization from Sco X-1, noting spurious instrumental polarization due to cosmic ray anisotropy using X ray polarimeter