SIMBAD references

2009MNRAS.398..561W - Mon. Not. R. Astron. Soc., 398, 561-574 (2009/September-2)

Stellar velocity profiles and line strengths out to four effective radii in the early-type galaxies NGC3379 and 821.

WEIJMANS A.-M., CAPPELLARI M., BACON R., DE ZEEUW P.T., EMSELLEM E., FALCON-BARROSO J., KUNTSCHNER H., McDERMID R.M., VAN DEN BOSCH R.C.E. and VAN DE VEN G.

Abstract (from CDS):

We use the integral-field spectrograph SAURON to measure the stellar line-of-sight velocity distribution and absorption line strengths out to four effective radii (Re) in the early-type galaxies NGC 3379 and 821. With our newly developed observing technique, we can now probe these faint regions in galaxies that were previously not accessible with traditional long-slit spectroscopy. We make optimal use of the large field-of-view and high throughput of the spectrograph: by adding the signal of all ∼1400 lenslets into one spectrum, we obtain sufficient signal-to-noise in a few hours of observing time to reliably measure the absorption line kinematics and line strengths out to large radius.

We find that the line strength gradients previously observed within 1 Re remain constant out to at least 4 Re, which puts constraints on the merger histories of these galaxies. The stellar halo populations are old and metal poor. By constructing orbit-based Schwarzschild dynamical models, we find that dark matter is necessary to explain the observed kinematics in NGC 3379 and 821, with 30-50 per cent of the total matter being dark within 4 Re. The radial anisotropy in our best-fitting halo models is less than in our models without halo, due to differences in orbital structure. The halo also has an effect on the Mgb-Vescrelation: its slope is steeper when a dark matter halo is added to the model.


Abstract Copyright: © 2009 The Authors. Journal compilation © 2009 RAS

Journal keyword(s): galaxies: elliptical and lenticular, cD - galaxies: haloes - galaxies: individual: NGC 3379 - galaxies: individual: NGC 821 - galaxies: kinematics and dynamics - dark matter

Simbad objects: 4

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:2009MNRAS.398..561W and select 'bookmark this link' or equivalent in the popup menu