The study of ionized gas morphology and kinematics in nine eXtremely Metal-Deficient (XMD) galaxies with the scanning Fabry-Perot interferometer on the SAO 6-m telescope is presented. Some of these very rare objects (with currently known range of O/H of 7.12 < 12+log(O/H) < 7.65, or Zo/35 < Z < Zo/10) are believed to be the best proxies of `young' low-mass galaxies in the high-redshift Universe. One of the main goals of this study is to look for possible evidence of star formation (SF) activity induced by external perturbations. Recent results from HI mapping of a small subsample of XMD star-forming galaxies provided confident evidence for the important role of interaction-induced SF. Our observations provide complementary or new information that the great majority of the studied XMD dwarfs have strongly disturbed gas morphology and kinematics or the presence of detached components. We approximate the observed velocity fields by simple models of a rotating tilted thin disc, which allow us the robust detection of non-circular gas motions. These data, in turn, indicate the important role of current/recent interactions and mergers in the observed enhanced star formation. As a by-product of our observations, we obtained data for two LSB dwarf galaxies: Anon J012544+075957 that is a companion of the merger system UGC 993, and SAO 0822+3545 which shows off-centre, asymmetric, low SFR star-forming regions, likely induced by the interaction with the companion XMD dwarf HS 0822+3542.
Diversity of Ionized Gas Structures in Nearby Metal-poor Dwarf Galaxies
University of Tsukuba(筑波大学);Tsukuba Institute for Advanced Research (TIAR), University of Tsukuba(筑波大学先进研究院);Tomonaga Center for the History of the Universe (TCHoU), Faculty of Pure and Applied Sciences, University of Tsukuba(筑波大学理学院朝永振一郎宇宙历史中心);The University of Tokyo(东京大学);Stockholm University(斯德哥尔摩大学);Universidad Nacional Autónoma de México, Instituto de Astronomía(墨西哥国立自治大学天文学研究所);Nagoya University(名古屋大学);Waseda University(早稻田大学)
Cold molecular gas distribution and kinematics in the low-metallicity dusty starburst of Mrk 996 resolved with ALMA
Universidad de Talca(塔尔卡大学);Universidad de La Serena(拉塞雷纳大学);Instituto de Astrofísica de Andalucía, CSIC(安达卢西亚天体物理学研究所,西班牙国家研究委员会);Centro de Estudios de Física del Cosmos de Aragón (CEFCA)(阿拉贡宇宙物理研究中心);University of Michigan(密歇根大学);Space Telescope Science Institute(太空望远镜科学研究所);INAF - Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台)