Population Synthesis of Radio and γ‐Ray Millisecond Pulsars from the Galactic Disk

Abstract

We present results of a population synthesis of millisecond pulsars from the Galactic disk. Excluding globular clusters, we model the spatial distribution of millisecond pulsars by assuming their birth in the Galactic disk with a random kick velocity and evolve them to the present within the Galactic potential. We assume that normal and millisecond pulsars are standard candles described with a common radio luminosity model that invokes a new relationship between radio core and cone emission suggested by recent studies. In modeling the radio emission beams, we explore the relativistic effects of time delay, aberration and sweepback of the open field lines. While these effects are essential in understanding pulse profiles, the phase-averaged flux is adequately described without a relativistic model. We use a polar cap acceleration model for the γ-ray emission. We present the preliminary results of our recent study and the implications for observing millisecond pulsars with GLAST and AGILE.

Gamma-ray pulsars: A gold mine

“…In particular, it was suggested that deep radio searches of Fermi-LAT sources could discover MSPs, leading to detection of their γ-ray pulsations [42]. A Pulsar Search Consortium (PSC) undertook searches at radio and X-ray wavelengths at the positions of unidentified γ-ray sources that were non-variable and had hard spectra with high-energy cutoffs.…”

One blind and three targeted searches for (sub)millisecond pulsars

“…Several models have been proposed over the years to characterize the population of pulsars in the Galaxy, either ordinary (Lyne et al 1985;Yusifov & Küçük 2004;Lorimer et al 2006;Faucher-Giguère & Kaspi 2006), millisecond (Lorimer et al 1996;Cordes & Chernoff 1997;Story et al 2007), or both (Lyne et al 1998;Faucher-Giguère & Loeb 2010).…”

“…The luminosity distribution of ordinary pulsars has been modeled by one or two power laws (Lyne et al 1998;Guseinov et al 2003). Models where the luminosity distribution depends on the pulsar period and its derivative have also been considered, for both millisecond and ordinary pulsars (Story et al 2007). The flux A7, page 8 of 11 density was computed by multiplying the luminosity by the square of the distance to the synthetic pulsar.…”

Accelerating High-Energy Pulsar Radiation Codes

“…Other authors have used different definitions of κ(x) and ω CR (e.g., Harding 1981;Daugherty & Harding 1982;Cheng & Zhang 1996;Story et al 2007;Venter et al 2009b):…”

“…Such computationally expensive calculations are needed, for example, if one intends to study radiation properties of a sizable population of pulsars (e.g., Story et al 2007), or for examining the cumulative emission generated by an ensemble of MSPs believed to be responsible for the HE emission recently detected by Fermi-LAT from several globular clusters (GCs; Abdo et al 2009Abdo et al , 2010c. In addition to CR calculations, this also holds for computing X-ray to gamma-ray SR spectral components.…”