FLASH Talks: Guilherme Limberg (Universidade de São Paulo) & Zhefu Yu (The Ohio State University)
Friday, 09 December 2022 1 p.m. — 2 p.m. MST
NOIRLab Headquarters | 950 North Cherry Ave., Tucson, AZ 85719
Guilherme Limberg (Universidade de São Paulo) & Zhefu Yu (The Ohio State University)
Guilherme Limberg, Universidade de São Paulo
Footprints of the Milky Way’s Last Major Merger
The Milky Way is usually regarded as the benchmark for studies of galaxy evolution, in particular of its massive spiral siblings. In this context, the chemodynamical properties of stars in the Galactic halo are particularly suitable for us to reconstruct its hierarchical formation as they represent the debris left behind by accreted dwarf galaxies. This talk will focus on the footprints of the Gaia Sausage Enceladus disrupted dwarf galaxy, the culprit of the Milky Way’s last major merger. I will discuss how several observables in our Galaxy can be explained as consequences of this single merger.
Zhefu Yu, The Ohio State University
Mapping the Growth of Supermassive Black Holes with the OzDES Reverberation Mapping Project
Accurate mass measurements for supermassive black holes (SMBHs) are critical for understanding their growth over cosmic time. Outside of the local Universe, reverberation mapping (RM) of active galactic nuclei (AGN) is the most accurate method for measuring SMBH masses. RM measures the time lag between the continuum and broad emission line region (BLR) variability of AGN, which gives the virial mass when combined with the broad line width. I will present the latest results from the Dark Energy Survey (DES) - Australian DES (OzDES) RM project, which monitored 735 AGNs for 6 years with weekly photometry and monthly spectroscopy. Our results include some of the highest-quality Mg II lags and a new relationship between the radius of the Mg II BLR radius and the continuum luminosity (R-L relation). I will also describe our latest results on the Hbeta and C IV R-L relation. These R-L relations are extremely important because they are widely used to estimate the masses for large numbers of SMBHs from single-epoch spectra and study the SMBH demographics in a wide range of redshift. I will also present AGN accretion disk size measurements from continuum reverberation mapping, and simulations of the survey strategy of future RM campaigns to maximize the scientific yields.