Stellar Disk Evolution and Gaseous Disk Turbulence of Dwarf Irregular Galaxies

ISBN-13: 9783662528655 / Angielski / Twarda / 2016 / 165 str.

Hong-Xin Zhang

Opis

This book focuses on the stellar disk evolution and gas disk turbulence of the most numerous galaxies in the local Universe - the dwarf galaxies.

Spis treści

Introduction.- Dwarf Irregular Galaxies.- Star Formation in Dwarf Irregular Galaxies.- Star Formation Histories of Dwarf Irregular Galaxies.- Stellar Disk Evolution: Spiral Galaxies vs. Dwarf Irregular Galaxies.- Power Spectra, Turbulence and Cool Gas.- Interstellar Medium Turbulence and the Power Spectra.- From Power Spectral Variation with Channels to Multiple Temperature Components of HI gas The LITTLE THINGS Project.- Other Survey Projects on Dwarf Galaxies.- References.- Stellar Disk Evolution of Dwarf Irregular Galaxies.- Surface Photometry.- Multi-band Radial Surface Brightness Profiles.- Multi-band Spectral Energy Distribution Modeling.- Star Formation History Variations with Galactocentric Radius.- Double Exponential Stellar Mass Surface Profiles.- Discussion.- References.- Turbulence and Multiple Temperature Components of HI Gas in Dwarf Irregular Galaxies.- Sample and Data Reduction.- Fourier Transform Power Spectral Variation with Channel Width.- Comparison with the Visibility-based Power Spectra.- Effective Velocity Thickness and the Widespread Multiple Temperature Components of HI Gas.- Relation Between Power Spectral Indices and Star Formation.- Turbulent Velocity Power Spectra.- Discussion.- References.- Nearby Major Mergers – Another Type of Irregular Galaxies.- The Antennae Galaxies.- Data and Photometry.- Variation of Spectral Energy.- Distributions Across the Merging Disks.- Modeling of the Spectral Energy Distributions and the Derived Star Formation Histories.- Discussion.- References.- Conclusions.

O autorze

Dr. Hong-Xin Zhang received his Ph.D. in Astrophysics from the University of Chinese Academy of Sciences in July 2012. His major research project was on the star formation history variations and the interstellar medium turbulence in nearby galaxies. Subsequently, he became a post-doc fellow working with Prof. Eric Peng at the Department of Astronomy, Peking University, focusing on studying the nature of Ultra-compact Dwarf Galaxies in the Virgo Cluster.

Blurb

This book focuses on the stellar disk evolution and gas disk turbulence of the most numerous galaxies in the local Universe – the dwarf galaxies. The “outside-in” disk shrinking mode was established for a relatively large sample of dwarf galaxies for the first time, and this is in contrast to the “inside-out” disk growth mode found for spiral galaxies. Double exponential brightness profiles also correspond to double exponential stellar mass profiles for dwarf galaxies, which is again different from most spiral galaxies. The cool gas distribution in dwarf galaxies was probed with the spatial power spectra of hydrogen iodide (HI) gas emission, and provided indirect evidence that inner disks of dwarf galaxies have proportionally more cool gas than outer disks. The finding that no correlation exists between gas power spectral indices and star formation gave important constraints on the relation between turbulence and star formation in dwarf galaxies.