The population of pulsars with interpulses and the implications for beam evolution

نویسندگان

  • Patrick Weltevrede
  • Simon Johnston
چکیده

The observed fraction of pulsars with interpulses, their period distribution and the observed pulse width versus pulse period correlation is shown to be inconsistent with a model in which the angle α between the magnetic axis and the rotation axis is random. This conclusion appears to be unavoidable, even when non-circular beams are considered. Allowing the magnetic axis to align from a random distribution at birth with a timescale of ∼ 7 × 10 years can, however, explain those observations well. The timescale derived is consistent with that obtained via independent methods. The probability that a pulsar beam intersects the line of sight is a function of the angle α and therefore beam evolution has important consequences for evolutionary models and for estimations of the total number of neutron stars. The validity of the standard formula for the spin-down rate, which is independent of α appears to be questionable.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Optimization of Beam Orientation and Weight in Radiotherapy Treatment Planning using a Genetic Algorithm

Introduction: The selection of suitable beam angles and weights in external-beam radiotherapy is at present generally based upon the experience of the planner. Therefore, automated selection of beam angles and weights in forward-planned radiotherapy will be beneficial. Material and Methods: In this work, an efficient method is presented within the MATLAB environment to investigate how to improv...

متن کامل

On the Evolution of Pulsar

We have analyzed polarization data for a large number of isolated pulsars to investigate the evolution of pulsar radio beams. Assuming that a circular beam is directed along the axis of a dipolar magnetic eld, we demonstrate that the distribution of magnetic inclination angles for the parent population of all pulsars is not at but highly concentrated towards small inclination angles and that, c...

متن کامل

Emission Beam Geometry of Selected Pulsars Derived from Average Pulse Polarization Data

By fitting the classical Rotating Vector Model (RVM) to high quality polarization data for selected radio pulsars, we find the inclination of the magnetic axis to the spin axis, α, as well as the minimum angle between the line of sight and the magnetic axis, β, for ten objects. We give a full treatment of statistical errors in the fitting process. We also present a dictionary and conversion tab...

متن کامل

Highest Brightness Temperature Observed in the Universe

Giant radio pulses of the millisecond pulsar B1937+21 were recorded with the S2 VLBI system at 1.65 GHz with NASA/JPL’s 70-m radio telescope at Tidbinbilla, Australia. These pulses have been observed as strong as 65 000 Jy with widths ≤ 15 ns, corresponding to a brightness temperature Tb ≥ 5 · 10 39 K, the highest observed in the universe. The vast majority of these pulses occur in a 5.8 μs and...

متن کامل

Evolution of Black Widow Pulsars

We consider the evolution of black widow pulsars (BWPs). The large majority of these are members of globular clusters. For minimum companion masses < 0.1M ̄, adiabatic evolution and consequent mass loss under gravitational radiation appear to provide a coherent explanation of all observable properties. We suggest that the group of BWPs with minimum companion masses ∼> 0.1M ̄ are systems relaxing ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:

دوره   شماره 

صفحات  -

تاریخ انتشار 2008