Speaker
Description
Recent observations have revealed a Cosmic Microwave Background (CMB) temperature decrement toward local galaxies within the 2MASS Redshift Survey. We examine this detection by investigating its frequency dependence and sensitivity to component separation methods, indicating that Galactic foregrounds are unlikely responsible. Unlike previous studies, our findings show the decrement is independent of galaxy type, suggesting a possible correlation between the CMB and the overall matter density field. To investigate this hypothesis, we utilize three analytical methods: cross-correlation analysis, template fitting, and Bayes Factor calculation. Our results consistently demonstrate a moderate correlation (with significance levels between 1% - 5%) between the CMB and the 2MASS Redshift Survey projected matter density at distances under 50 Mpc/h. Notably, this signal is not detected beyond 50 Mpc/h, which limits potential physical interpretations and highlights the need for caution regarding possible look-elsewhere effects in our analysis. We discuss that the physical origin of this correlation may potentially be connected to dark matter distribution in galaxy halos. Additional research is necessary to validate and elucidate this relationship between the CMB and local matter distribution.