Understanding the cosmic growth of supermassive black hole (BH) population and coevolution with their host galaxies is now one of the essential ingredients for a complete picture of galaxy formation and evolution. This talk will show you the results of the related two observational research projects.
(1) To directly map the BH-galaxy coevolution, we investigate the cosmic evolution of the...
Understanding the cosmic growth of supermassive black hole (BH) population and coevolution with their host galaxies is now one of the essential ingredients for a complete picture of galaxy formation and evolution. This talk will show you the results of the related two observational research projects.
(1) To directly map the BH-galaxy coevolution, we investigate the cosmic evolution of the BH mass-bulge luminosity scaling relationship using a sample of 52 AGNs at z~0.36 and z~0.57. By employing multi-component spectral and structural decomposition methods to the obtained high-quality Keck spectra and high-resolution HST images, BH masses and bulge luminosities are measured uniformly and consistently. Using Monte Carlo simulations to take into account selection effects, we find the observational evidence that BH growth precedes that of the host galaxies. This indicates that black holes grow first and then the host galaxies follow up in the framework of the BH-galaxy coevolution.
(2) To probe the high-redshift BH population and scaling relations, measuring BH masses accurately is the first crucial step. The rest-frame UV CIV broad emission line is usually used for BH mass estimates in high-redshift AGNs (i.e.2
Formation and evolution of low HI mass galaxies are affected by environment and by the photoionisation feedback from the UV background after end of reionization. We study the physical processes of low HI mass galaxy formation which are imprinted on the distribution of neutral hydrogen in the Universe using the hierarchical galaxy formation model, GALFORM. We calculate the sensitivity of correlatio...
Formation and evolution of low HI mass galaxies are affected by environment and by the photoionisation feedback from the UV background after end of reionization. We study the physical processes of low HI mass galaxy formation which are imprinted on the distribution of neutral hydrogen in the Universe using the hierarchical galaxy formation model, GALFORM. We calculate the sensitivity of correlation functions to the HI mass threshold at redshifts $0 \le z \le 0.5$. Parameterizing clustering as $\xi(z)=(r/r_{0})^{-\gamma}$, we find that low HI mass galaxies increase the clustering amplitude $r_{0}$ and slope $\gamma$ in HI selected galaxy samples. This is opposite to expectations from optical galaxy surveys. We show the HI mass function for different host dark matter halo masses and types (central or satellite) to interpret the clustering of HI galaxies. We also show the contribution of low HI mass galaxies to 21cm intensity mapping. We find that semi-analytic modelling of intensity mapping requires a dark matter halo mass resolution of $<$10$^{10}{\rm h}^{-1}$M$_{\odot}$ in order to correctly predict 21cm brightness temperature fluctuations.