Poster Abstract

P.12 Mengxin Wang (The National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) )

Stellar population analysis on the stacked spectra of double-peaked emission-line galaxies

The double-peaked emission-line galaxies has long been perceived as objects re-lated with merging galaxies or other phenomena of disturbed dynamical activities, such as
outflows and disk rotation. In order to find the connection between the unique activities happening in these objects and their stellar population physics, we study the stellar populations
of the stacked spectra drawn from double-peaked emission-line galaxies in LAMOST DR4 and SDSS DR7 database. We group the selected double-peaked emission-line objects into 10 different types of pairs based on the BPT diagnosis for each pair of blue-shifted and red-shifted components, and then stack the spectra of each group for analysis. The software STARLIGHT is employed to fit each stacked spectra, and the contributions of stars at different ages and metallicities are quantified for subsequent comparative study and analysis. To highlight the commonness and uniqueness in these double-peaked emitting objects, we compare the population synthesis results of the stacked spectra of double-peaked emission-line galaxies with that of their
counterpart reference samples appearing single-peaked emission features. The reference sample are also selected from LAMOST DR4 and SDSS DR7 databases, respectively. From the
comparison results, we confirm the strong correlations between the stellar populations and its
spectral classes, and find that the double-peaked emitting phenomena is more likely to occur
in the ‘older’ stellar environment and the subgroups hosting different BPT components will
show obvious heterogeneous star formation history.