NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-05-19 T22:08:00 PDT
Help | Comment | NED Home

For refcode 2001MNRAS.323..615K:
Retrieve 85 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by Royal Astronomical Society. 2001MNRAS.323..615K On the dependence of spectroscopic indices of early-type galaxies on age, metallicity and velocity dispersion Harald Kuntschner, John R. Lucey, Russell J. Smith, Michael J. Hudson and Roger L. Davies Accepted 2000 November 15. Received 2000 November 15; in original form 2000 August 14 ABSTRACT We investigate the Mg-{sigma} and <Fe>-{sigma} relations in a sample of 72 early-type galaxies drawn mostly from cluster and group environments using a homogeneous data set which is well calibrated on to the Lick/IDS system. The small intrinsic scatter in Mg at a given {sigma} gives upper limits on the spread in age and metallicity of 49 and 32 per cent respectively, if the spread is attributed to one quantity only, and if the variations in age and metallicity are uncorrelated. The age/metallicity distribution as inferred from the H{beta} versus <Fe> diagnostic diagram reinforces this, as we find mostly galaxies with large luminosity-weighted ages spanning a range in metallicity. Using Monte Carlo simulations, we show that the galaxy distribution in the H{beta} versus <Fe> plane cannot be reproduced by a model in which galaxy age is the only parameter driving the index- {sigma} relation. In our sample we do not find significant evidence for an anticorrelation of ages and metallicities which would keep the index- {sigma} relations tight while hiding a large spread in age and metallicity. As a result of correlated errors in the age-metallicity plane, a mild age- metallicity anticorrelation cannot be completely ruled out by the current data. Correcting the line-strength indices for non-solar abundance ratios, following the recent paper by Trager et al., leads to higher mean metallicity and slightly younger age estimates while preserving the metallicity sequence. The [Mg/Fe] ratio is mildly correlated with the central velocity dispersion, and ranges from [Mg/Fe]=0.05 to 0.3 for galaxies with {sigma} > 100 km s^-1^. Under the assumption that there is no age gradient along the index-{sigma} relations, the abundance-ratio- corrected Mg-{sigma},Fe-{sigma} and H{beta}-{sigma} relations give consistent estimates of {DELTA}[M/H]/{DELTA} log {sigma} ~ 0.9+/-0.1. The slope of the H{beta}-{sigma} relation limits a potential age trend as a function of {sigma} to 2-3 Gyr along the sequence. Keywords: galaxies: abundances - galaxies: elliptical and lenticular, cD - galaxies: formation - galaxies: kinematics and dynamics
Retrieve 85 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home