Speaker
Description
Measuring the expansion rate of the Universe, quantified by the Hubble constant (H₀), is an important problem in modern cosmology. In this study, we aim to estimate the Hubble constant by using fast radio bursts (FRBs) detected with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) radio telescope. Current measurements show a significant discrepancy between early-Universe probes, such as the cosmic microwave background, and late-Universe observations based on the cosmic distance ladder. This so-called Hubble tension suggests that the current cosmological model may be incomplete. FRBs provide an alternative approach. There is a close relation between the dispersion measure of FRB and its host redshift, and we can take advantage of it to constrain the H₀. However, the small sample of FRBs with securely identified host galaxies limits the availability of direct redshift measurements and reduces statistical power. In this work, we analyze a large sample of unlocalized FRBs from the CHIME Baseband Catalog. We statistically associate FRBs with galaxies from the Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) using the Probabilistic Association of Transients to their Hosts (PATH) framework, enabling probabilistic redshift estimation. To reliably constrain the Hubble constant (H₀) , we compare the inferred DM–redshift relation with the expected Macquart relation. We construct probability density functions for the redshift of each FRB and assign weights based on galaxy number counts in the catalogs. Using this approach, we could get more obviously trend to estimate the value of H₀.
| Participate the oral/poster presentation award competition | Yes |
|---|