The SLUGGS survey: a new mask design to reconstruct the stellar populations and kinematics of both inner and outer galaxy regions

TL;DR

This paper introduces the SuperSKiMS mask design for the DEIMOS spectrograph, enabling large-scale, high-resolution stellar kinematic and metallicity mapping of galaxies, extending observations to faint outer regions and matching integral field spectroscopy results.

Contribution

The paper presents a novel mask design that allows large-scale, high-resolution stellar population and kinematic studies of galaxies using multislit spectroscopy, bridging the gap with integral field spectroscopy.

Findings

Successfully simulated the mask on NGC 1023, reaching faint outer regions.

Reproduced 2D kinematic and metallicity distributions consistent with IFU data.

Obtained stellar velocity dispersion measurements matching literature results.

Abstract

Integral field unit spectrographs allow the 2D exploration of the kinematics and stellar populations of galaxies, although they are generally restricted to small fields-of-view. Using the large field-of-view of the DEIMOS multislit spectrograph on Keck and our Stellar Kinematics using Multiple Slits (SKiMS) technique, we are able to extract sky-subtracted stellar light spectra to large galactocentric radii. Here we present a new DEIMOS mask design named SuperSKiMS that explores large spatial scales without sacrificing high spatial sampling. We simulate a set of observations with such a mask design on the nearby galaxy NGC 1023, showing that the kinematic and metallicity measurements can reach radii where the galaxy surface brightness is several orders of magnitude fainter than the sky. Such a technique is also able to reproduce the kinematic and metallicity 2D distributions obtained from literature integral field spectroscopy in the innermost galaxy regions. In particular, we use the simulated NGC 1023 kinematics to model its total mass distribution to large radii, obtaining comparable results with those from published integral field unit observation. Finally, from new spectra of NGC 1023 we obtain stellar 2D kinematics and metallicity distributions that show good agreement with integral field spectroscopy results in the overlapping regions. In particular, we do not find a significant offset between our SKiMS and the ATLAS$^\rm{3D}$ stellar velocity dispersion at the same spatial locations.