Dr. Hong-Xin ZHANG (张红欣)
Professor of Astronomy
Department of Astronomy, University of Science and Technology of China Hefei, Anhui 230026, China Lihua Building, Rm 18-012 hzhang18 at ustc.edu.cn
Research
Formation and Evolution of Galaxies: from Dwarfs to Giants
Galaxies are the lighthouses of the mostly dark Universe, and they span more than six orders of magnitude in luminosities and masses. The formation and evolution of galaxies have been deeply influencing both the visible and invisible (e.g., dark matter) parts of the Universe. The general topic of galaxy formation and evolution is at the forefront of modern astrophysics. Our research touches several aspects of nearby dwarf and giant galaxies, including their stellar structures, kinematics, interstellar medium, and how these properties change in response to interactions between galaxies. We enjoy the practice of learning physical properties of galaxies by synthesizing (aided by models and simulations) multi-wavelength observational data taken from various telescopes. See here for details of our research.
The picture to the right (Image Credit: ESA/Hubble/R.Gendler) shows an optical view of the Andromeda Galaxy (the nearest giant neighbor of the Milky Way) and its dwarf companioons. Besides the "host" Andromeda Galaxy, the most spectacular satellite galaxies visible in the picture are the Compact Elliptical galaxy M32 (slightly to the left of Andromeda's center) and the Dwarf Elliptical galaxy NGC 205 (to the bottom right of the center).
Research Group
Postdocs
Zesen Lin (林泽森), 2020-2022, (research topics: interstellar gas and dust, star clusters)
Our discovery of a gas-rich dwarf merger event was highlighted by the American Astronomical Society Nova (click the picture for more)
Our study of neutral atomic hydrogen gas and numerical simulations of a dwarf merger was highlighted by Nature Astronomy (click the picture for more)
Our discovery of a similar mass-metallicity relation of UCDs and nuclei of dwarf elliptical galaxies was highlighted by Nature Astronomy (click the picture for more)
Worldwide Telescopes used for our Research
Telescopes working in the optical and near-infrared can collect information about stellar ages, chemical abundances, kinematics and masses; telescopes working in the far-infrared can collect information about the dust obscured stellar populations; telescopes working in the (sub-)mm wavelengths can collect information about properties of cold gas that is nursery of new star formation; telescopes working in the mm to cm wavelengths can collect information about warm-hot gas properties that may be affected by star formation or active galactic nuclei.
Dwarf galaxies with the highest concentration are not thicker than ordinary dwarf galaxies , L. J. Chen, H.-X. Zhang^{*}, Z. Lin et al., 2023, arXiv:2309.05052, ApJ in press
Unveiling the formation of NGC 2915 with MUSE: A counter-rotating stellar disk embedded in a disordered gaseous environment , Y. M. Tang, B.J. Tao, H.-X. Zhang^{*}, G.W. Chen et al., 2022, A&A, 668, 179
Discovery of a Bimodal Environmental Distribution of Compact Ellipticals in the Local Universe , G.W. Chen, H.-X. Zhang^{*}, X. Kong^{*} et al., 2022, ApJL, 934, 2
The Blue Compact Dwarf Galaxy VCC 848 Formed by Dwarf-Dwarf Merging: HI Gas, Star Formation, and Numerical Simulations, H.-X. Zhang, R. Smith, S.-H. Oh, P. Sanjaya et al., 2020, ApJ, 900, 2
The Blue Compact Dwarf Galaxy VCC 848 Formed by Dwarf-Dwarf Merging, H.-X. Zhang, P. Sanjaya, R. Smith, P.-A., Duc, T.H. Puzia et al., 2020, ApJL, 891, L23
