Molecular and atomic gas in dust lane early-type galaxies - I: Low star-formation efficiencies in minor merger remnants
Timothy A. Davis, Kate Rowlands, James R. Allison, Stanislav S. Shabala, Yuan-Sen Ting, Claudia del P. Lagos, Sugata Kaviraj, Nathan Bourne, Loretta Dunne, Stev… 展开作者
Timothy A. Davis, Kate Rowlands, James R. Allison, Stanislav S. Shabala, Yuan-Sen Ting, Claudia del P. Lagos, Sugata Kaviraj, Nathan Bourne, Loretta Dunne, Steve Eales, Rob J. Ivison, Steve Maddox, Daniel J. B. Smith, Matthew. W. L. Smith, Pasquale Temi
In this work we present IRAM-30m telescope observations of a sample of bulge-dominated galaxies with large dust lanes, which have had a recent minor merger. We find these galaxies are very gas rich, with H2 masses between 4x10^8 and 2x10^10 Msun. We use these molecular gas masses, combined with atomic gas masses from an accompanying paper, to calculate gas-to-dust and gas-to-stellar mass ratios. The gas-to-dust ratios of our sample objects vary widely (between ~50 and 750), suggesting many objects have low gas-phase metallicities, and thus that the gas has been accreted through a recent merger with a lower mass companion. We calculate the implied minor companion masses and gas fractions, finding a median predicted stellar mass ratio of ~40:1. The minor companion likely had masses between ~10^7 - 10^10 Msun. The implied merger mass ratios are consistent with the expectation for low redshift gas-rich mergers from simulations. We then go on to present evidence that (no matter which star-formation rate indicator is used) our sample objects have very low star-formation efficiencies (star-formation rate per unit gas mass), lower even than the early-type galaxies from ATLAS3D which already show a suppression. This suggests that minor mergers can actually suppress star-formation activity. We discuss mechanisms that could cause such a suppression, include dynamical effects induced by the minor merger.
From short-lived to long-lived clouds: impact of star formation models on giant molecular cloud evolution in simulations of an NGC 300-like galaxy
Yonsei University（延世大学）；Korea Astronomy and Space Science Institute（韩国天体物理与空间科学研究所）；Korea Institute for Advanced Study（韩国高等研究院）；University of Chicago（芝加哥大学）；Centre de Recherche Astrophysique de Lyon UMR5574, Univ Lyon, Univ Lyon1, Ens de Lyon（里昂天体物理研究中心）
Can Little Red Dots Contribute To The Early Universe Cosmic Dust Budget?
University of Hawai‘i at Mānoa（夏威夷大学马诺阿分校）；Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究所）；The University of Texas at Austin（德克萨斯大学奥斯汀分校）；Princeton University（普林斯顿大学）；MIT Kavli Institute for Astrophysics and Space Research（麻省理工学院卡弗里天体物理与空间研究所）
