THE STAR-FORMING HISTORIES OF THE NUCLEUS, BULGE, AND INNER DISK OF NGC 5102: CLUES TO THE EVOLUTION OF A NEARBY LENTICULAR GALAXY^,,

Abstract

Long slit spectra recorded with GMOS on Gemini South are used to examine the star-forming history of the lenticular galaxy NGC 5102. Structural and supplemental photometric information are obtained from archival Spitzer [3.6] images. Absorption features at blue and visible wavelengths are traced out along the minor axis to galactoentric radii ∼ 60 arcsec (∼ 0.9 kpc), sampling the nucleus, bulge, and disk components. Comparisons with model spectra point to luminosity-weighted metallicities that are consistent with the colors of resolved red giant branch stars in the disk. The nucleus has a luminosity-weighted age at visible wavelengths of ∼ 1 +0.2 −0.1 Gyr, and the integrated light is dominated by stars that formed over a time period of only a few hundred Myr. For comparison, the luminosity-weighted ages of the bulge and disk are ∼ 2 +0.5 −0.2 Gyr and 10 +2 −2 Gyr, respectively. The g ′ − [3.6] colors of the nucleus and bulge are consistent with the spectroscopically-based ages. In contrast to the nucleus, models that assume

Intermediate-mass Early-type Disk Galaxies in the Virgo Cluster. II. Near-Infrared Spectra and Evidence for Differences in Evolution* † ‡ † ‡

“…Davidge & Courteau 2002;Georgiev & Boker 2014), dwarf lenticulars (e.g. Seth et al 2010;Davidge 2015a), and dwarf galaxies in Virgo (Cote et al 2006).…”

“…Both are relatively isolated and contain central populations with ages < 1 Gyr (Seth et al 2010;Davidge 2015a). The radial metallicity profile of NGC 5102 suggests that the current morphology might be the result of the buckling of the bar in an LMC-like galaxy (Davidge 2015a). NGC 55 is a nearby irregular galaxy in a low density environment that may be transitioning into a dwarf lenticular morphology (Davidge 2018b;2019).…”

The JCMT Gould Belt Survey: Dense Core Clusters in Orion B

“…Young stellar clusters tend to show signs of present-day mass segregation, which, given the approximate age of the systems, is often interpreted as implying that the segregation is at least partially primordial (e.g., Carpenter et al 1997;Bonnell & Davies 1998;Hillenbrand & Hartmann 1998;Gouliermis et al 2004;Stolte et al 2006;Gennaro et al 2011;Kirk & Myers 2011;Davidge 2015). Note, however, that in more crowded systems, there are several observational biases which need to be carefully considered to measure true mass segregation (Ascenso et al 2009).…”

Dominant dark matter and a counter-rotating disc: MUSE view of the low-luminosity S0 galaxy NGC 5102

“…There is some uncertainty about the distance to NGC 5102: values based on the Planetary Nebula luminosity function tend to find shorter distances of 3.1 Mpc (McMillan et al 1994). The distances obtained from tip of the red-giant branch measurements scatter: Karachentsev et al (2002) find a distance of 3.4 Mpc, Davidge (2008) The photometry of NGC 5102 shows the typical features of an S0 galaxy: a bulge that follows a r 1/4 profile and a disc with a flatter profile at larger radii (Pritchet 1979;Davidge 2015). The central deviation from the r 1/4 profile builds the nucleus.…”

“…Using long slit spectra, with the slit oriented along the minor axis of the galaxy, Davidge (2015) determine a luminosity weighted SSP age for the nucleus and bulge of 1 +0.2 −0.1 and 2 +0.5 −0.2 Gyr respectively. From Lick index measure-ments Davidge (2015) find a (spatially) roughly constant metallicity of Z = 0.004 for NGC 5102. For the disc Beaulieu et al (2010) find a declining SFR over the last 0.2 Gyr and a recently quiescent SFR.…”