TY - JOUR
T1 - Constraining Alternative Theories of Gravity Using Pulsar Timing Arrays
AU - Cornish, Neil J.
AU - O'Beirne, Logan
AU - Taylor, Stephen R.
AU - Yunes, Nicolás
N1 - Publisher Copyright:
© 2018 American Physical Society.
PY - 2018/5/4
Y1 - 2018/5/4
N2 - The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations. Here, we show that existing results from pulsar timing arrays can be used to place stringent limits on the energy density of longitudinal stochastic gravitational waves. However, unambiguously distinguishing these modes from noise will be very difficult due to the large variances in the pulsar-pulsar correlation patterns. Existing upper limits on the power spectrum of pulsar timing residuals imply that the amplitude of vector longitudinal (VL) and scalar longitudinal (SL) modes at frequencies of 1/year are constrained, AVL<4×10-16 and ASL<4×10-17, while the bounds on the energy density for a scale invariant cosmological background are ΩVLh2<4×10-11 and ΩSLh2<3×10-13.
AB - The opening of the gravitational wave window by ground-based laser interferometers has made possible many new tests of gravity, including the first constraints on polarization. It is hoped that, within the next decade, pulsar timing will extend the window by making the first detections in the nanohertz frequency regime. Pulsar timing offers several advantages over ground-based interferometers for constraining the polarization of gravitational waves due to the many projections of the polarization pattern provided by the different lines of sight to the pulsars, and the enhanced response to longitudinal polarizations. Here, we show that existing results from pulsar timing arrays can be used to place stringent limits on the energy density of longitudinal stochastic gravitational waves. However, unambiguously distinguishing these modes from noise will be very difficult due to the large variances in the pulsar-pulsar correlation patterns. Existing upper limits on the power spectrum of pulsar timing residuals imply that the amplitude of vector longitudinal (VL) and scalar longitudinal (SL) modes at frequencies of 1/year are constrained, AVL<4×10-16 and ASL<4×10-17, while the bounds on the energy density for a scale invariant cosmological background are ΩVLh2<4×10-11 and ΩSLh2<3×10-13.
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U2 - 10.1103/PhysRevLett.120.181101
DO - 10.1103/PhysRevLett.120.181101
M3 - Article
C2 - 29775330
AN - SCOPUS:85046547318
SN - 0031-9007
VL - 120
JO - Physical review letters
JF - Physical review letters
IS - 18
M1 - 181101
ER -