文章基本信息

标题：The H i Chronicles of LITTLE THINGS BCDs. III. Gas Clouds in and around Mrk 178, VII Zw 403, and NGC 3738
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作者：Trisha Ashley ; Caroline E. Simpson ; Bruce G. Elmegreen 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2017
卷号：153
期号：3
DOI：10.3847/1538-3881/aa5ca7
语种：English
出版社：American Institute of Physics
摘要：In most blue compact dwarf (BCD) galaxies, it remains unclear what triggers their bursts of star formation. We study the H i of three relatively isolated BCDs, Mrk 178, VII Zw 403, and NGC 3738, in detail to look for signatures of star formation triggers, such as gas cloud consumption, dwarf–dwarf mergers, and interactions with companions. High angular and velocity resolution atomic hydrogen (H i) data from the Very Large Array (VLA) dwarf galaxy H i survey, Local Irregulars That Trace Luminosity Extremes, The H i Nearby Galaxy Survey (LITTLE THINGS), allow us to study the detailed kinematics and morphologies of the BCDs in H i. We also present high-sensitivity H i maps from the NRAO Green Bank Telescope (GBT) of each BCD to search their surrounding regions for extended tenuous emission or companions. The GBT data do not show any distinct galaxies obviously interacting with the BCDs. The VLA data indicate several possible star formation triggers in these BCDs. Mrk 178 likely has a gas cloud impacting the southeast end of its disk or it is experiencing ram pressure stripping. VII Zw 403 has a large gas cloud in its foreground or background that shows evidence of accreting onto the disk. NGC 3738 has several possible explanations for its stellar morphology and H i morphology and kinematics: an advanced merger, strong stellar feedback, or ram pressure stripping. Although apparently isolated, the H i data of all three BCDs indicate that they may be interacting with their environments, which could be triggering their bursts of star formation.
关键词：galaxies: dwarf;galaxies: individual (Mrk 178; VII Zw 403; NGC 3738);galaxies: star formation