How do neutron stars slow down?
K. Yavuz Ekşi
Abstract: Neutron stars are compact objects of radius R ~10 km and masses of 1.5–2 solar mass. They are rapidly rotating objects with spin periods P ∼ 0.01 − 10 s; some have even shorter and some have much longer periods. Neutron stars are strongly magnetized objects with typical magnetic ﬁelds B ∼ 1012 G; some have 3 orders of magnitude smaller and larger ﬁelds. The misalignment of the rotation and magnetic axis leads to the so called “lighthouse eﬀect” by which we observe pulsed emission as the beamed emission from the magnetic poles sweep our line of sight. We can thus measure the spin period of a pulsar precisely and even determine its change over time. Of the ∼ 2700 pulsars discovered to date most are rotationally powered pulsars (RPPs) i.e. objects radiating at the expense of their rotational kinetic energy. It is generally conceived that these objects spin-down under the magnetic dipole radiation torque, but observations suggest that other processes must also be involved. Of these processes I will review our recent works about the alignment of the rotation and magnetic axis [1,2], and the growth [3,4] and decay  of the magnetic ﬁeld of neutron stars at diﬀerent stages.