The Sluggs Survey: Wide-Field Stellar Kinematics of Early-Type Galaxies

Abstract

We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line stellar spectroscopy out to ∼ 2-4 R e (effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a factor of 20 in intrinsic luminosity, as well as a full range of environment and ETG morphology. Our data consist of good velocity resolution (σ inst ∼ 25 km s −1 ) integrated stellar-light spectra extracted from the individual slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics measurements (V , σ, h 3 , and h 4 ) for each galaxy. Combining with literature values from smaller radii, we present 2D spatially resolved maps of the large-scale kinematic structure in each galaxy. We find that the kinematic homogeneity found inside 1 R e often breaks down at larger radii, where a variety of kinematic behaviors are observed. While central slow rotators remain slowly rotating in their halos, central fast rotators show more diversity, ranging from rapidly increasing to rapidly declining specific angular momentum profiles in the outer regions. There are indications that the outer trends depend on morphological type, raising questions about the proposed unification of the elliptical and lenticular (S0) galaxy families in the ATLAS 3D survey. Several galaxies in our sample show multiple lines of evidence for distinct disk components embedded in more slowly rotating spheroids, and we suggest a joint photometric-kinematic approach for robust bulge-disk decomposition. Our observational results appear generally consistent with a picture of two-phase (in-situ plus accretion) galaxy formation.

SUPERMASSIVE BLACK HOLES AND THEIR HOST SPHEROIDS. II. THE RED AND BLUE SEQUENCE IN THE MBH–M*,SPH DIAGRAM

“…Kinematical information Arnold et al 2014;Scott et al 2014) was used to confirm the presence of rotationally supported disk components in most early-type (elliptical + lenticular) galaxies, and to identify their extent (intermediate-scale disks that are fully embedded in the bulge, or large-scale disks that encase the bulge and dominate the light at large radii). It is worth stressing that, contrary to common knowledge, the majority of "elliptical" galaxies contain disks, i.e.,they are not singlecomponent spheroidal systems.…”

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

“…Nevertheless, Meert et al (2015) provide B/T decompositions for their Sérsic-Exponential reductions, which we have used to estimate M bulge in the SDSS. Savorgnan et al (2016) also considered detailed galaxy decompositions that take into account spheroid, discs, spiral arms, bars, rings, halo, extended or unresolved nuclear source and partially depleted core, and checked for consistency with galaxy kinematics (e.g., Arnold et al 2014). So, we have used bulge stellar masses to see how the offset in the top right panel of Figure 1 changes when we replace Mstar → M bulge .…”

The SLUGGS survey: combining stellar and globular cluster metallicities in the outer regions of early-type galaxies

“…In order to reduce the DEIMOS spectra, we adopt a modified version of the IDL spec2D pipeline (Cooper et al 2012;Newman et al 2013), as presented in Arnold et al (2014). In multi-slit mode, from a single DEIMOS slit, it is possible to obtain the spectra of both the target object and the background light.…”

“…While the former is used to study the GC stellar population properties, the latter includes light from both the galaxy's stars and the night sky. Adopting the "Stellar Kinematics with Multiple Slits" (SKiMS) technique (Norris et al 2008;Proctor et al 2009;Foster et al 2009;Pastorello et al 2014;Arnold et al 2014;Foster et al 2015), it is possible to separate the two components in the background spectra and obtain an individual spectrum of the GC and the galaxy starlight at each slit location.…”