Speaker
Description
The precise measurement of the Hubble constant remains a central challenge in modern cosmology, particularly given the tension between early-universe ( cosmic microwave background) and late-universe ( Type Ia supernovae) measurements. Independent probes are essential for clarifying the origin of this discrepancy. Fast Radio Bursts (FRBs) possess the potential to offer a unique alternative. The unique measurement of FRBs, dispersion measure (DM) in the intergalactic space, serves as a proxy for the cosmological distance measure. Combined with independent measurements of redshift (z), the DM-z relation can constrain the Hubble constant, analogous to the Hubble diagram for Type Ia supernovae. However, largely due to the observational challenges of precise localization, fewer than 10% of the total FRB samples have identified host galaxies, limiting the statistical power of their cosmological utility. To address this, we propose a statistical method using the angular cross-correlation between FRBs in wide-field surveys and galaxies in large-scale galaxy surveys. By correlating FRBs in DM bins with galaxies in redshift bins, we reconstruct the probability distribution on the DM-z plane without requiring individual host identifications. This method enables us to measure the Hubble constant using unlocalized FRBs, which significantly outnumber the localized ones, thereby providing strong statistical power owing to their large numbers. We will demonstrate this method with mock-FRB samples and will present preliminary results using the latest data from the second CHIME/FRB Catalog and DESI Legacy Imaging Surveys. Our results demonstrate the potential of FRB-galaxy cross-correlations as a robust, independent cosmological probe.
| Participate the oral/poster presentation award competition | No |
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