To further study the relationship between the black hole mass and the velocity dispersion of galaxies in the low redshift universe. The images of approximately more than 1000 galaxies in the HST public data archive are suitable for this study. Luis Ho’s team have analyzed the images of all type I AGNs in HST archive by using the software GALFIT, however more works should be done to determine the types of bulges of galaxies. And then, the team will focus on how the scaling relationship evolve with redshift. Although many astronomers have done some researches in this field, our team has a lot of advantages to get more detailed measurements of the relevant physical parameters. The scaling relationship between black holes and the stellar masses in galaxies have been widely believed to be the evidence of the close connection of the formations of the two components, but how to achieve it? Is the black hole growth occurs during, before or after the period of star formation? In observation, the order of these two processes can be studied by comparing the accretion rates of black holes and the star formation rates in their host galaxies.
We will estimate the accretion rates from the SED or the single-epoch spectra of quasars. If the black hole masses are measured reliably, the accretion rates can be measured with the help of accretion disk model. The other way is to obtain the dimensionless accretion rates from the single-epoch spectra using the fundamental plane of the BLR. On the other hand, several methods can be adopted to determine the star formation rates. Our team has multi-wavelength data from the sample of PG quasars (z < 0.5). It is very suitable for the research of this problem. Ran Wang and Linhua Jiang took part in the research work of AGNs in COSMOS field observed by JCMT, providing a useful sample of intermediate redshift. It offers opportunities to test the relationship between the accretion rates of black holes and the star formation rates in galaxies.
Observational test and theoretical model of AGN feedback is one of the key parts in this project. We plan to test the feedback generated by the interaction of black hole activities and gas, using the radio observation of FAST (we can detect the HI of z~0.4), or measuring the mass of gas from the typical molecular lines and dust. Ran Wang and her collaborators have significantly expanded the sample of gas in the host galaxies of quasars in the early universe. Ho’s group has also obtained a complete sample of the infrared spectra (1-500micron) of PG quasars with z<0.5, and the data of type II quasars selected from SDSS. In addition, we will study the evidence of feedback from the X-ray observations. Detailed numerical simulations will also reveal the physics of feedback. And we will also use the large local sample from SDSS, as well as the data of multi-band images in redshift 0~1 and spectroscopic survey of COSMOS and zCOSMOS, to study large scale structure of the universe, the interaction between galaxies, merges, and the triggering of AGNs. Jingwen Wu and his collaborators discovered that the Hot DOG dusty quasars are in the most violent phase of accretion and feedback. Those objects may exist in any periods of the universe. The further search and study on them will be helpful to the understanding of black hole activity under extreme conditions.