The Leo Triplet: Common origin or late encounter?

Abstract

The kinematics, structure, and stellar population properties in the centers of two early-type spiral galaxies of the Leo Triplet, NGC 3623 and NGC 3627, are studied by means of integral-field spectroscopy. Unlike our previous targets, NGC 3384/NGC 3368 in the Leo I group and NGC 5574/NGC 5576 in LGG379, NGC 3623 and NGC 3627 do not appear to experience a synchronous evolution. The mean ages of their circumnuclear stellar populations are quite different, and the magnesium overabundance of the nucleus in NGC 3627 is evidence for a very brief last star formation event 1 Gyr ago whereas the evolution of the central part of NGC 3623 looks more quiescent. In the center of NGC 3627 we observe noticeable gas radial motions, and the stars and the ionized gas in the center of NGC 3623 demonstrate more or less stable rotation. However, NGC 3623 has a chemically distinct core -- a relic of a past star formation burst -- which is shaped as a compact, dynamically cold stellar disk with a radius of about 250-350 pc which has been formed not later than 5 Gyr ago.

13 pages, 14 figures, accepted for publication in Astronomy and Astrophysics

References in corpus (4)

• Stellar population models of Lick indices with variable element abundance ratios
• The SAURON project - III. Integral-field absorption-line kinematics of 48 elliptical and lenticular galaxies
• A Study of the Direct-Fitting Method for Measurement of Galaxy Velocity Dispersions
• The Leo I Cloud: Secular nuclear evolution of NGC 3379, NGC 3384, and NGC 3368?

Cited by in corpus (13)

• The SAURON project - VII. Integral-field absorption and emission-line kinematics of 24 spiral galaxy bulges
• Warm molecular hydrogen in the Spitzer SINGS galaxy sample
• The SAURON project - XI. Stellar Populations from Absorption Line Strength Maps of 24 Early-Type Spirals
• The Central Kiloparsec of Seyfert and Inactive Host Galaxies: a Comparison of Two-Dimensional Stellar and Gaseous Kinematics
• H-alpha Kinematics of the SINGS Nearby Galaxies Survey. II
• Mid-Infrared Fine Structure Line Ratios in Active Galactic Nuclei Observed with Spitzer IRS: Evidence for Extinction by the Torus
• Stellar Populations of Bulges in 14 Cluster Disc Galaxies
• Absorption line-strengths of 18 late-type spiral galaxies observed with SAURON
• The Arecibo Legacy Fast ALFA Survey: IX. The Leo Region HI Catalog, Group Membership and the HI Mass Function for the Leo I Group
• Molecular gas in the centre of nearby galaxies from VLT/SINFONI integral field spectroscopy - II. Kinematics
• Hickson 62.I. Kinematics of NGC4778
• HI mapping of the Leo Triplet: Morphologies and kinematics of tails and bridges
• Synchronous Evolution of Galaxies in Groups: NGC 524 Group