EVIDENCE for the RAPID FORMATION of LOW-MASS EARLY-TYPE GALAXIES in DENSE ENVIRONMENTS

Yiqing Liu, Eric W. Peng, John Blakeslee, Patrick Côté, Laura Ferrarese, Andrés Jordán, Thomas H. Puzia, Elisa Toloba, Hong Xin Zhang

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

We explore the environmental dependence of star formation timescales in low-mass galaxies using the [α/Fe] abundance ratio as an evolutionary clock. We present integrated [α/Fe] measurements for 11 low-mass () early-type galaxies (ETGs) with a large range of cluster-centric distance in the Virgo Cluster. We find a gradient in [α/Fe], where the galaxies closest to the cluster center (the cD galaxy, M87) have the highest values. This trend is driven by galaxies within a projected radius of 0.4 Mpc (0.26 times the virial radius of Virgo A), all of which have super-solar [α/Fe]. Galaxies in this mass range exhibit a large scatter in the [α/Fe]-σ diagram, and do not obviously lie on an extension of the relation defined by massive ETGs. In addition, we find a correlation between [α/Fe] and globular cluster specific frequency (SN), suggesting that low-mass ETGs that formed their stars over a short period of time were also efficient at forming massive star clusters. The innermost low-mass ETGs in our sample have [α/Fe] values comparable to that of M87, implying that environment is the controlling factor for star formation timescales in dense regions. These low-mass galaxies could be the surviving counterparts of the objects that have already been accreted into the halo of M87, and may be the link between present-day low-mass galaxies and the old, metal-poor, high-[α/Fe], high-SN stellar populations seen in the outer halos of massive ETGs.

Original languageEnglish
Article number179
JournalAstrophysical Journal
Volume818
Issue number2
DOIs
StatePublished - 20 Feb 2016
Externally publishedYes

Keywords

  • galaxies: abundances
  • galaxies: clusters: individual (Virgo)
  • galaxies: dwarf
  • galaxies: formation
  • galaxies: star clusters: general

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