Research

Research Interests

Galaxy formation and evolution
Structural parameters of galaxies
High redshift galaxies
Connection between AGN, star formation, and galaxy morphology

Current Research

In CEA-Saclay, I am working on the MORPHOSTAR (Morphological and multi-wavelength constraints on the coeval growth of galaxies and their super-massive black holes) project. I focus on mid-IR power-law emission selected AGNs, which are complementary samples of X-ray selected AGNs. I fit optical to far-infrared photometry by the latest SED techniques to derive stellar masses, star formation rates, dust properties, and AGN contribution in the COSMOS field. I also explore galaxy morphologies through ACS and WFC3 images, which provide structural properties of galaxy stellar component at high redshift. I compare AGN host galaxies with other star-forming galaxies and discuss the effect of nuclear activity on galaxy structures and their evolution (Chang et al, in prep.).

Past Research

SDSS+WISE

Chang et al., 2015, ApJS, 219, 8
The catalogs are available:
SDSS+WISE MAGPHYS catalog.

ETGs in CANDELS

The oblate fraction of massive early-type galaxies that were distinctly oblate was 3 times larger and triaxial fraction was 2 times smaller at z ~ 2 compared to the present day universe.
Chang et al., 2013b, ApJ, 773, 149.

Massive ETGs

At z < 2, the most massive early-type galaxies are the roundest.
Chang et al. 2013a, ApJ, 762, 83