Frequency-Dependent Template Profiles for High Precision Pulsar Timing. (arXiv:1812.02006v1 [astro-ph.HE])

<a href="http://arxiv.org/find/astro-ph/1/au:+Pennucci_T/0/1/0/all/0/1">Timothy T. Pennucci</a>

Pulsar timing experiments require high fidelity template profiles in order to

minimize the biases in pulse time-of-arrival (TOA) measurements and their

uncertainties. Efforts to acquire more precise TOAs given fixed effective area

of telescopes, finite receiver noise, and limited integration time have led

pulsar astronomers to the solution of implementing ultra-wideband receivers.

This solution, however, has run up against the problem that pulse profile

shapes evolve with frequency, which raises the question of how to properly

measure and analyze TOAs obtained using template-matching methods. This paper

proposes a new method for one facet of this problem, that of template profile

generation, and demonstrates it on the well-timed millisecond pulsar

J1713+0747. Specifically, we decompose pulse profile evolution into a linear

combination of basis eigenvectors, the coefficients of which change slowly with

frequency such that their evolution is modeled simply by a sum of low degree

piecewise polynomial spline functions. These noise-free, high fidelity,

frequency-dependent templates can be used to make measurements of so-called

“wideband TOAs” simultaneously with an estimate of the instantaneous dispersion

measure. The use of wideband TOAs is becoming important for pulsar timing array

experiments, as the volume of datasets comprised of conventional, subbanded

TOAs are quickly becoming unwieldly for the Bayesian analyses needed to uncover

latent gravitational wave signals. Although motivated by high precision timing

experiments, our technique is applicable in more general pulsar observations.

Pulsar timing experiments require high fidelity template profiles in order to

minimize the biases in pulse time-of-arrival (TOA) measurements and their

uncertainties. Efforts to acquire more precise TOAs given fixed effective area

of telescopes, finite receiver noise, and limited integration time have led

pulsar astronomers to the solution of implementing ultra-wideband receivers.

This solution, however, has run up against the problem that pulse profile

shapes evolve with frequency, which raises the question of how to properly

measure and analyze TOAs obtained using template-matching methods. This paper

proposes a new method for one facet of this problem, that of template profile

generation, and demonstrates it on the well-timed millisecond pulsar

J1713+0747. Specifically, we decompose pulse profile evolution into a linear

combination of basis eigenvectors, the coefficients of which change slowly with

frequency such that their evolution is modeled simply by a sum of low degree

piecewise polynomial spline functions. These noise-free, high fidelity,

frequency-dependent templates can be used to make measurements of so-called

“wideband TOAs” simultaneously with an estimate of the instantaneous dispersion

measure. The use of wideband TOAs is becoming important for pulsar timing array

experiments, as the volume of datasets comprised of conventional, subbanded

TOAs are quickly becoming unwieldly for the Bayesian analyses needed to uncover

latent gravitational wave signals. Although motivated by high precision timing

experiments, our technique is applicable in more general pulsar observations.

http://arxiv.org/icons/sfx.gif