Projects
Here I list several interesting projects that I have participated in or am working on.
Dynamical modeling of Broad-line Regions
(On-going)
Dynamical modeling of broad-line region enables independent measurement for BH mass and the virial factor. I am currently working on using Caramel to model ~15 high-luminosity AGNs from SAMP project. This will provide the first investigation to the geometric and kinematic properties of high-luminosity AGNs.
New method to identify Changing-look AGNs
Promising in the era of LSST
Changing-look AGNs are those AGNs showing emergence/disappearance of broad lines. The mechanism for the transitions are still open questions. Here, we develop a new method to identify changing-look AGNs using variability characteristics. Using Gemini 8 m and MDM 2.4 m telescope to perform follow-up observation, we identify 17 turn-on and 4 turn-off changing-look AGNs. Compared to previous method, it shows much larger success rate of ~80%. (More details)
Novel approach for BH mass estimtation
As shown in the right figure, our investigation reveals a similar size-luminosity relation between continuum emitting regions and broad-line regions. This enables a much more efficient direct estimation for BH mass estimation using continuum RM, which could have significant impact in the era of LSST. (More details)
Non evolution of Metallicity in AGN Broad-line Regions up to z~6
We studied the metallicity in the broad-line region of 33 quasars at 4.7<z<6.4. We found that the metallicity inferred from line ratios is comparable to z~2 quasars. The Fe II / Mg II ratio, which reflects the early Type-Ia SN history, also shows no evolution up to z~6. These results suggest the chemical enrichment at central region must be much more earlier. (More details)
