PENENTUAN NILAI KONSTANTA HUBBLE DENGAN MENGGUNAKAN DATA BARYON ACOUSTIC OSCILLATIONS (BAO)

• Main Author: Salam Al Amin, Nur
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42850
• Institution: Institut Teknologi Bandung

Hubble's constant measures the current rate of development of the universe. In addition, the value is needed in determining other quantities that are important in cosmology. Therefore the determination of the Hubble constant becomes an important issue in astronomy. The main obstacle in determining the value of the Hubble constant is the calculation of the distance that must be precise. In general, the method of determining the Hubble constant is divided into two major groups, namely the distance ladder method on low redshift (local scale) and cosmological observations on high redshift (global scale). Since 2003 there has been a tension between the local and global observations, which has not been resolved until now. Even the results of the local determination represented by SN Ia (Riess, 2019) are in 4.4? mismatch with the global determination represented by Planck 2018 (Planck Collaboration, 2018). In this Final Project, the Hubble constant is determined using a global method using Baryon Acoustic Oscillations (BAO) data. BAO is a photon-baryon's fluid harmonic oscillation event in the potential for dark matter before the decopling era. Perturbations in the photon-baryon's fluid spread out at the speed of sound. After the decopling era, photons will be decoupled from protons and electrons and spread free (free streaming), while the baryons will be left behind and stacked on a radius called the drag radius, which is nothing but the sound horizon radius (~ 150 Mpc). In this Final Project the Hubble constant is determined using the MCMC method in the CosmoMC program package. BAO data used in the form of tertiary data from universe survey projects, namely SDSS, WiggleZ, 6dfGS, and DR14Lyman. In addition to the BAO data, the Planck 2018 CMB-TT (Temperature) data is used as a comparison as well as to tighten the constraints for determining cosmological parameters. Priors are defined following the standard model ?CDM. In general, the results of determining Hubble's constant BAO data are consistent with results with CMB.