{
"id": "1901.03321",
"version": "v1",
"published": "2019-01-10T18:57:37.000Z",
"updated": "2019-01-10T18:57:37.000Z",
"title": "Standard sirens with a running Planck mass",
"authors": [
"Macarena Lagos",
"Maya Fishbach",
"Philippe Landry",
"Daniel E. Holz"
],
"categories": [
"astro-ph.CO"
],
"abstract": "We consider the effect of a time-varying Planck mass on the propagation of gravitational waves (GWs). A running Planck mass arises naturally in several modified gravity theories, and here we focus on those that carry an additional dark energy field responsible for the late-time accelerated expansion of the universe, yet---like general relativity (GR)---propagate only two GW polarizations, both traveling at the speed of light. Because a time-varying Planck mass affects the amplitude of the GWs and therefore the inferred distance to the source, standard siren measurements of $H_0$ are degenerate with the parameter $c_M$ characterizing the time-varying Planck mass, where $c_M=0$ corresponds to GR with a constant Planck mass. The effect of non-zero $c_M$ will have a noticeable impact on GWs emitted by binary neutron stars (BNSs) at the sensitivities and distances observable by ground-based GW detectors such as advanced LIGO and A+, implying that standard siren measurements can provide joint constraints on $H_0$ and $c_M$. Taking Planck's measurement of $H_0$ as a prior, we find that GW170817 constrains $c_M = -9^{+21}_{-28}$ ($68.3\\%$ credibility). We also discuss forecasts, finding that if we assume $H_0$ is known independently (e.g.~from the cosmic microwave background), then 100 BNS events detected by advanced LIGO can constrain $c_M$ to within $\\pm0.9$. This is comparable to the current best constraints from cosmology. Similarly, for 100 LIGO A+ BNS detections, it is possible to constrain $c_M$ to $\\pm0.5$. When analyzing joint $H_0$ and $c_M$ constraints we find that $\\sim 400$ LIGO A+ events are needed to constrain $H_0$ to $1\\%$ accuracy. Finally, we discuss the possibility of a nonzero value of $c_M$ biasing standard siren $H_0$ measurements from 100 LIGO A+ detections, and find that $c_M=+1.35$ could bias $H_0$ by 3--4$\\sigma$ too low if we incorrectly assume $c_M=0$.",
"revisions": [
{
"version": "v1",
"updated": "2019-01-10T18:57:37.000Z"
}
],
"analyses": {
"keywords": [
"running planck mass",
"time-varying planck mass",
"dark energy field responsible",
"standard siren measurements",
"additional dark energy field"
],
"note": {
"typesetting": "TeX",
"pages": 0,
"language": "en",
"license": "arXiv",
"status": "editable"
}
}
}