The MASSIVE survey - III. Molecular gas and a broken Tully-Fisher relation in the most massive early-type galaxies

Timothy A. Davis, Jenny Greene, Chung Pei Ma, Viraj Pandya, John P. Blakeslee, Nicholas McConnell, Jens Thomas

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

In this work, we present CO(1-0) and CO(2-1) observations of a pilot sample of 15 earlytype galaxies (ETGs) drawn from the MASSIVE galaxy survey, a volume-limited integralfield spectroscopic study of the most massive ETGs (M* ≳ 1011.5 M⊙) within 108 Mpc. These objects were selected because they showed signs of an interstellar medium and/or star formation. A large amount of gas (>2 × 108 M⊙) is present in 10 out of 15 objects, and these galaxies have gas fractions higher than expected based on extrapolation from lower mass samples. We tentatively interpret this as evidence that stellar mass-loss and hot halo cooling may be starting to play a role in fuelling the most massive galaxies. These MASSIVE ETGs seem to have lower star formation efficiencies (SFE = SFR/MH2) than spiral galaxies, but the SFEs derived are consistent with being drawn from the same distribution found in other lower mass ETG samples. This suggests that the SFE is not simply a function of stellar mass, but that local, internal processes are more important for regulating star formation. Finally, we used the CO line profiles to investigate the high-mass end of the Tully-Fisher relation (TFR). We find that there is a break in the slope of the TFR for ETGs at high masses (consistent with previous studies). The strength of this break correlates with the stellar velocity dispersion of the host galaxies, suggesting it is caused by additional baryonic mass being present in the centre of massive ETGs. We speculate on the root cause of this change and its implications for galaxy formation theories.

Original languageEnglish (US)
Pages (from-to)214-226
Number of pages13
JournalMonthly Notices of the Royal Astronomical Society
Volume455
Issue number1
DOIs
StatePublished - Jan 1 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • CD
  • Galaxies: ISM
  • Galaxies: elliptical and lenticular
  • Galaxies: evolution
  • Galaxies: kinematics and dynamics
  • Galaxies: star formation
  • ISM: molecules

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