Constraining the ellipticity of millisecond pulsars with observed spin-down rates

Abstract

A spinning neutron star (NS) that is asymmetric with respect to its spin axis can emit continuous gravitational wave (GW) signals. The spin frequencies and their distribution of radio millisecond pulsars (MSPs) and accreting MSPs provide some evidences of GW radiation, and MSPs are ideal probes detecting high frequency GW signals. It is generally thought that MSPs originate from the recycled process, in which the NS accretes the material and angular momentum from the donor star. The accreted matter would be confined at the polar cap zone by an equatorial belt of compressed magnetic field fixed in the deep crust of the NS, and yields "magnetic mountain". Based on an assumption that the spin-down rates of three transitional MSPs including PSR J1023+0038 are the combinational contribution of the accretion torque, the propeller torque, and the GW radiation torque, in this work we attempt to constrain the ellipticities of MSPs with observed spin-down rates. Assuming some canonical parameters of NSs, the ellipticities of three transitional MSPs and ten redbacks are estimated to be $\epsilon =(0.9-23.4)\times 10^{-9}$. The electrical resistivities of three transitional MSPs are also derived to be in the range $\eta =(1.2-15.3)\times 10^{-31}\mathrm{s}$, which display an ideal power law relation with the accretion rate. The characteristic strains ($h_{\mathrm{c}}=(0.6-2.5)\times 10^{-27}$) of GW signals emitting by these sources are obviously beyond the sensitivity scope of the aLIGO. We expect that the third-generation GW detectors like the Einstein Telescope can seize the GW signals from these sources in the future.

7 pages, 2 figures. PRD in press

References in corpus (26)

• GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral
• The ATNF Pulsar Catalogue
• A Radio Pulsar/X-ray Binary Link
• Maximum elastic deformations of compact stars with exotic equations of state
• Detecting gravitational wave emission from the known accreting neutron stars
• Eight New Millisecond Pulsars in NGC 6440 and NGC 6441
• The Green Bank Northern Celestial Cap Pulsar Survey - I: Survey Description, Data Analysis, and Initial Results
• Upper limits on gravitational wave emission from 78 radio pulsars
• Discovery of PSR J1227-4853: A transition from a low-mass X-ray binary to a redback millisecond pulsar
• Optical spectroscopy and demographics of redback millisecond pulsar binaries
• The Spin Distribution of Fast Spinning Neutron Stars in Low Mass X-Ray Binaries: Evidence for Two Sub-Populations
• Spin-Down of Radio Millisecond Pulsars at Genesis
• Timing Observations of PSR J1023+0038 During a Low-Mass X-ray Binary State
• First all-sky search for continuous gravitational waves from unknown sources in binary systems
• Gamma-ray Timing of Redback PSR J2339-0533: Hints for Gravitational Quadrupole Moment Changes
• Unveiling the redback nature of the low-mass X-ray binary XSSJ1227.0-4859 through optical observations
• The Effect of Transient Accretion on the Spin-Up of Millisecond Pulsars
• Resistive relaxation of a magnetically confined mountain on an accreting neutron star
• The Spin Distribution of Millisecond X-ray Pulsars
• Improved estimate of the detectability of gravitational radiation from a magnetically confined mountain on an accreting neutron star
• The High Time Resolution Universe Survey - XI. Discovery of five recycled pulsars and the optical detectability of survey white dwarf companions
• Ejector and propeller spin-down: How might a superluminous supernova millisecond magnetar become the 6.67 hr pulsar in RCW103
• The Quasi-Roche lobe overflow state in the evolution of Close Binary Systems containing a radio pulsar
• Formation of redbacks via accretion induced collapse
• High braking index pulsar PSR J1640-4631: low-mass neutron star with a large inclination angle?
• X-ray study of high-and-low luminosity modes and peculiar low-soft-and-hard activity in the transitional pulsar XSS J12270-4859

Cited by in corpus (8)

• Searches for Continuous-Wave Gravitational Radiation
• Searches for continuous gravitational waves from neutron stars: A twenty-year retrospective
• Ultra-compact X-ray binaries as dual-line gravitational-wave sources
• Gravitational waves from neutron-star mountains
• Spin evolution of neutron stars in two modes: implication for millisecond pulsars
• Ultra-compact binary pulsars as continuous dual-line gravitational wave sources
• On the minimum spin period of accreting pulsars
• On the Gravitational Wave Counterpart to a Gamma-ray Galactic Center Signal from Millisecond Pulsars