# Exact Solutions and Accelerating Universe in Modified Brans-Dicke Theories

## TL;DR

This paper derives exact solutions in modified Brans-Dicke theory, exploring models that explain late-time cosmic acceleration and signature flips in the deceleration parameter, supported by observational data constraints.

## Contribution

It introduces a novel application of the Euler-Duarte-Moreira method to solve modified Brans-Dicke equations and analyzes their cosmological implications with observational data.

## Key findings

- Some solutions exhibit eternal acceleration.
- Others show a recent signature flip in deceleration.
- Model parameters are constrained by multiple observational datasets.

## Abstract

Exact solutions are studied in the context of modified Brans-Dicke theory. The non-linearity of the modified Brans-Dicke field equations is treated with the Euler-Duarte-Moreira method of integrability of anharmonic oscillator equation. While some solutions show a forever accelerating nature, in some cases there is a signature flip in the evolution of deceleration parameter in recent past. Importance of these latter models are studied in the context of late-time acceleration of the universe. Constraints on the model parameters are obtained from Markov Chain Monte Carlo (MCMC) analysis using the Supernova distance modulus data, observational measurements of Hubble parameter, Baryon acoustic oscillation data, and the CMB Shift parameter data.