High Frequency Cutoff and Change of Radio Emission Mechanism in Pulsars
V. M. Kontorovich, A. B. Flanchik
备注:
9 pages, 5 Postscript figures; The Report on the International Conference on Physics of Neutron Stars, Saint-Petersburg, Russia, 2011. Book of Abstracts, p. 75. The text has been revised in accordance with the reviewer's comments. Published in Astrophysics and Space Science Volume 345, Issue 1 (2013), Page 169-175 http://www.springerlink.com
Pulsars are the fast rotating neutron stars with strong magnetic field, that emit over a wide frequency range. In spite of the efforts during 40 years after the discovery of pulsars, the mechanism of their radio emission remains to be unknown so far. We propose a new approach to solving this problem for a subset of pulsars with a high-frequency cutoff of the spectrum from the Pushchino catalogue (the "Pushchino" sample). We provide a theoretical explanation of the observed dependence of the high-frequency cutoff from the pulsar period. The dependence of the cutoff position from the magnetic field is predicted. This explanation is based on a new mechanism for electron radio emission in pulsars. Namely, radiation occurs in the inner (polar) gap, when electrons are accelerated in the electric field that is increasing from zero level at the star surface. In this case acceleration of electrons passes through a maximum and goes to zero when the electron velocity approaches the speed of light. All the radiated power is located within the radio frequency band. The averaging of intensity radiation over the polar cap, with some natural assumptions of the coherence of the radiation, leads to the observed spectra. It also leads to an acceptable estimate of the power of radio emission.
Do all millisecond pulsars share a common heritage?
低质量X射线双星系统中中子星毫秒脉动的发现证实了毫秒射电双星与低质量X射线双星系统之间的联系。从那时起,从LMXB产生毫秒射电双星,然后由于偶极辐射而自旋下降的过程被认为是毫秒射电双星的“标准进化”。然而,是否所有观测到的毫秒射电暴都可以由LMXB产生的问题直到现在还没有得到定量的解决。标准的演化过程产生的毫秒周期(P)和自旋下降速率(Pdot)并不完全独立。毫秒级射电望远镜可能达到的P-Pdot值受到联合约束。为了检验观测到的毫秒射电天体是否是毫秒X射线天体(MSXP)的明确后代,我们制作了一张概率图,它代表了标准模型下毫秒射电天体的预期分布。我们以超过95%的置信度表明,在标准模型的框架内,所观测到的毫秒X射线天体不能产生具有高磁场的最快旋转毫秒射电天体,例如PSR B 1937 +21。