高能暂现源 · 每日文献综述

We conduct a cross-correlation analysis between large-scale structures traced by the Two Micron All Sky Survey (2MASS) galaxy catalog and the cosmic dispersion measures of 133 localized fast radio bursts (FRBs). The cross-correlation signal is measured as a function of the comoving separation R between 2MASS galaxies and background FRB sightlines, making full use of the available redshift information for both datasets. Our measurements are consistent with a null detection over the range <inline-formula><tex-math id="TM0001" notation="LaTeX">$0.01 \lt R\, [h^{-1}\, \mathrm{Mpc}] \lt 1$</tex-math></inline-formula>. Using a halo-based model in which free-electron density profiles are drawn from the hydrodynamical simulation IllustrisTNG-300 (TNG300), we show that the null signal at <inline-formula><tex-math id="TM0002" notation="LaTeX">$R \sim 0.01\, h^{-1}\, \mathrm{Mpc}$</tex-math></inline-formula> is inconsistent with the TNG300 prediction. This discrepancy indicates that the hot-gas mass fraction in halos with masses of <inline-formula><tex-math id="TM0003" notation="LaTeX">$10^{12-13}\, M_\odot$</tex-math></inline-formula> hosting 2MASS galaxies must be lower than that predicted by TNG300. A simple phenomenological modification of the TNG300 model suggests that the hot-gas mass fraction in halos of <inline-formula><tex-math id="TM0004" notation="LaTeX">$10^{12-13}\, M_\odot$</tex-math></inline-formula> should be below <inline-formula><tex-math id="TM0005" notation="LaTeX">${\sim }10\%$</tex-math></inline-formula> of the global baryon fraction in the nearby universe, implying the need for stronger feedback in this mass range. Our constraints are consistent with those inferred from X-ray emission and Sunyaev-Zel'dovich measurements in galaxies, while providing a direct estimate of the hot-gas mass fraction that does not rely on electron-temperature measurements. These results demonstrate that galaxy-FRB cross correlations offer a powerful probe of feedback processes in galaxy formation.