395,588 research outputs found
The superslow pulsation X-ray pulsars in high mass X-ray binaries
There exists a special class of X-ray pulsars that exhibit very slow
pulsation of s in the high mass X-ray binaries (HMXBs). We
have studied the temporal and spectral properties of these superslow pulsation
neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term
monitoring observations find spin period evolution of two sources: spin-down
trend for 4U 2206+54 ( s with s s) and long-term spin-up trend for 2S 0114+65
( s with s
s) in the last 20 years. A Be X-ray transient, SXP 1062 ( s), also showed a fast spin-down rate of s s during an outburst. These superslow
pulsation neutron stars cannot be produced in the standard X-ray binary
evolution model unless the neutron star has a much stronger surface magnetic
field ( G). The physical origin of the superslow spin period is
still unclear. The possible origin and evolution channels of the superslow
pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could
be younger X-ray binary systems, still in the fast evolution phase preceding
the final equilibrium state. Alternatively, they could be a new class of
neutron star system accreting magnetars.Comment: 4 pages, 3 figures. Oral talk for the Proceedings of IAUS 291
"Neutron Stars and Pulsars: Challenges and Opportunities after 80 years", J.
van Leeuwen (ed.
Supercritical Nonlinear Schr\"odinger equations: Quasi-Periodic Solutions
We construct time quasi-periodic solutions to the energy supercritical
nonlinear Schr\"odinger equations on the torus in arbitrary dimensions. This
introduces a new approach, which could have general applicability.Comment: 62 pages; Duke Math. J. (to appear
Low temperature latching solenoid
A magnetically latching solenoid includes a pull-in coil and a delatching coil. Each of the coils is constructed with a combination of wire materials, including material of low temperature coefficient of resistivity to enable the solenoid to be operated at cryogenic temperatures while maintaining sufficient coil resistance. An armature is spring-based toward a first position, that may extend beyond the field of force of a permanent magnet. When voltage is temporarily applied across the pull-in magnet, the induced electromagnetic forces overcome the spring force and pulls the armature to a second position within the field of the permanent magnet, which latches the armature in the pulled-in position. Application of voltage across the delatching coil induces electromagnetic force which at least partially temporarily nullifies the field of the permanent magnet at the armature, thereby delatching the armature and allowing the spring to move the armature to the first position
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