# Gravitational radiation from compact binary systems in screened modified gravity

## TL;DR

This paper examines how screening mechanisms in modified gravity theories influence gravitational wave emission from binary systems, deriving energy loss rates and constraining models using pulsar observations.

## Contribution

It provides detailed calculations of tensor and scalar gravitational radiation in screened modified gravity and constrains model parameters based on binary pulsar data.

## Key findings

- Scalar dipole radiation dominates orbital decay.
- Screening suppresses scalar effects in strongly self-gravitating bodies.
- Observations place tight constraints on screening mechanisms in SMG.

## Abstract

Screened modified gravity (SMG) is a kind of scalar-tensor theory with screening mechanisms, which can suppress the fifth force in dense regions and allow theories to evade the solar system and laboratory tests. In this paper, we investigate how the screening mechanisms in SMG affect the gravitational radiation damping effects, calculate in detail the rate of the energy loss due to the emission of tensor and scalar gravitational radiations, and derive their contributions to the change in the orbital period of the binary system. We find that the scalar radiation depends on the screened parameters and the propagation speed of scalar waves, and the scalar dipole radiation dominates the orbital decay of the binary system. For strongly self-gravitating bodies, all effects of scalar sector are strongly suppressed by the screening mechanisms in SMG. By comparing our results to observations of binary system PSR J1738+0333, we place the stringent constraints on the screening mechanisms in SMG. As an application of these results, we focus on three specific models of SMG (chameleon, symmetron, and dilaton), and derive the constraints on the model parameters, respectively.