The blue compact dwarf galaxy VCC 848 formed by dwarf-dwarf merging: H i gas, star formation and numerical simulations

作     者：Zhang, Hong-Xin Smith, Rory Oh, Se-Heon Paudel, Sanjaya Duc, Pierre-Alain Boselli, Alessandro Côté, Patrick Ferrarese, Laura Gao, Yu Hunter, Deidre A. Puzia, Thomas H. Peng, Eric W. Rong, Yu Shin, Jihye Zhao, Yinghe 

作者机构：Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei Anhui230026 China School of Astronomy and Space Science University of Science and Technology of China Hefei Anhui230026 China  776 Daedeokdae-ro Yuseong-gu Daejeon34055 Korea Republic of Department of Physics and Astronomy Sejong University 209 Neungdong-ro Gwangjin-gu Seoul Korea Republic of Department of Astronomy and Center for Galaxy Evolution Research Yonsei University Seoul03722 Korea Republic of Universit de Strasbourg CNRS Observatoire astronomique de Strasbourg UMR 7550 StrasbourgF-67000 France UMR 7326 MarseilleF-13388 France National Research Council of Canada Herzberg Astronomy and Astrophysics Program 5071 West Saanich Road VictoriaBCV9E 2E7 Canada Department of Astronomy Xiamen University XiamenFujian361005 China Purple Mountain Observatory Chinese Academy of Sciences 10 Yuanhua Road Nanjing210023 China Lowell Observatory 1400 West Mars Hill Road FlagstaffAZ86001 United States Instituto de Astrofsica Pontificia Universidad Catlica de Chile Macul Santiago7820436 Chile Department of Astronomy Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China 

出 版 物：《arXiv》 (arXiv)

年 卷 期：2020年

核心收录：

主　　题：Merging 

摘      要：A clear link between a dwarf-dwarf merger event and enhanced star formation (SF) in the recent past was recently identified in the gas-dominated merger remnant VCC 848, offering by far the clearest view of a gas-rich late-stage dwarf-dwarf merger. We present a joint analysis of JVLA H i emission-line mapping, optical imaging and numerical simulations of VCC 848, in order to examine the impact of the merger on the stellar and gaseous distributions. VCC 848 has less than 30% of its H i gas concentrated within the central high-surface-brightness star-forming region, while the remaining H i is entrained in outlying tidal features. Particularly, a well-defined tidal arm reaches N(H i) comparable to the galaxy center but lacks SF. The molecular gas mass inferred from the current SF rate (SFR) dominates over the atomic gas mass in the central ∼ 1.5 kpc. VCC 848 is consistent with being a main-sequence star-forming galaxy for its current stellar mass and SFR. The H ii region luminosity distribution largely agrees with that of normal dwarf irregulars with similar luminosities, except that the brightest H ii region is extraordinarily luminous. Our N-body/hydrodynamical simulations imply that VCC 848 is a merger between a gas-dominated primary progenitor and a gas-bearing star-dominated secondary. The progenitors had their first passage on a near-radial non-coplanar orbit more than 1 Gyr ago. The merger did not build up a core as compact as typical compact dwarfs with centralized starburst, which may be partly ascribed to the star-dominated nature of the secondary, and in a general sense, a negative stellar feedback following intense starbursts triggered at early stages of the merger. Copyright © 2020, The Authors. All rights reserved.