The inner structure of the S0 galaxy NGC 3384

Abstract

We re-investigate the lenticular galaxy NGC 3384, a member of the Leo I galaxy group, using HST and multi-colour Calar Alto observations. Various approaches are used to visualize the two known peculiar components, the so-called inner component (IC) and the elongated component (EC), on the HST images. The methods were checked in detail using synthetical images from simulated galaxies. For the first time, we make the IC as well as the inner part of the EC visible on direct images. The results confirm both the bar-like appearance of the inner EC and the quasi-elliptical shape of the IC. The IC resembles an inclined disk where the surface brightness becomes successively shallower towards the centre compared to an exponential profile. The orientation of the inner part of the EC is perpendicular to the major axis of the IC. The broad-band colour indices are shown to be in agreement with model predictions for a 5 to 7 Gyr old stellar population of quasi-solar metallicity. No significant large-scale variations of the colour indices over the main body of the galaxy are found. We discuss the previously reported colour gradients close to the nucleus and argue that the most plausible explanation is reddening by small amounts of dust though unsharp masked HST images do not provide significant hints for clumpy dust. According to the episodic dust settling scenario suggested by Lauer et al. (2005), the very low dust fraction indicates that NGC 3384 is in a post-activity phase and at the beginning of a new dust-settling cycle.

Fundamental Planes and the BarlessMBH‐σ Relation for Supermassive Black Holes

“…1), and NGC 3384 (Busarello et al 1996, their Fig. 7;Cappellari & Emsellem 2004;Erwin 2004;Meusinger & Ismail 2007).…”

The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy survey: The kinematic diversity of stellar halos and the relation between halo transition scale and stellar mass

“…Cortesi et al (2013b) performed a kinematic analysis of the disk and spheroid component separately. The photometric study of Meusinger & Ismail (2007) showed the presence of an "inner component" and and "elongated" component, visible in the PA phot profiles as a local minimum at R = 3" and a local maximum at R = 15". Therefore we considered only the regions at R > 30" in our discussion in section 8.4.…”

“…(e) Mean radius of the last radial bin in units of effective radii. (f) Average value of the photometric position angle and (g) ellipticity ( ), from Krajnović et al (2011) (within 2.5 − 3R e ) and Ho et al (2011) (in the outer regions, where they converge to a constant value) For NGC 3384 and NGC 4564 we used the PA phot from Meusinger & Ismail (2007) and Goudfrooij et al (1994), respectively. (*) Objects for which we used circular radial bins ( = 0) , see section 3.2.…”

Gaseous Merger Signatures in Early-Type Galaxies

“…The SB0-classification of NGC 3384 indicates the presence of a bar, which can increase ellipticities and should also produce boxy isophotes. There is no evidence for a bar in our data, which exhibit mildly disky behavior throughout, so any bar must be a larger scale feature (Meusinger et al 2007). The B 4 profile of NGC 7457 also does not have the large positive deviations expected of an inner disk.…”