Evidence for recent accretion in nearby galaxies

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

I discuss observations of magnitude residuals from the B-band Tully-Fisher relationship, B - V color, chemical abundance gradients, and asymmetries in the H I and stellar disks of nearby spiral galaxies within the context of a model in which small satellites or H I clouds are accreted onto the outer disks of spiral galaxies. Correlations between the various observables support the hypothesis that accretion dilutes the gas-phase abundances in the outer disk, steepens the abundance gradient across the disk, increases the star formation rate, and creates asymmetries in the outer disk. By estimating the duration of steep abundance gradients, elevated rates of star formation, or outer disk asymmetries, we can place constraints on the rate of accretion events. The data suggest that accretion events at the current time are common.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume448
Issue number1 PART 2
StatePublished - Jul 20 1995
Externally publishedYes

Fingerprint

accretion
galaxies
asymmetry
spiral galaxies
gradients
star formation rate
star formation
estimating
gas
vapor phases
color
rate

Keywords

  • Galaxies: abundances
  • Galaxies: evolution
  • Galaxies: interactions

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Evidence for recent accretion in nearby galaxies. / Zaritsky, Dennis F.

In: Astrophysical Journal, Vol. 448, No. 1 PART 2, 20.07.1995.

Research output: Contribution to journalArticle

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AB - I discuss observations of magnitude residuals from the B-band Tully-Fisher relationship, B - V color, chemical abundance gradients, and asymmetries in the H I and stellar disks of nearby spiral galaxies within the context of a model in which small satellites or H I clouds are accreted onto the outer disks of spiral galaxies. Correlations between the various observables support the hypothesis that accretion dilutes the gas-phase abundances in the outer disk, steepens the abundance gradient across the disk, increases the star formation rate, and creates asymmetries in the outer disk. By estimating the duration of steep abundance gradients, elevated rates of star formation, or outer disk asymmetries, we can place constraints on the rate of accretion events. The data suggest that accretion events at the current time are common.

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