Stellar kinematics and structural properties of Virgo cluster dwarf early-type galaxies from the SMAKCED project II. the survey and a systematic analysis of kinematic anomalies and asymmetries
: Toloba E., Guhathakurta P., Peletier R., Boselli A., Lisker T., Falc\'on-Barroso J., Simon J.D., van de Ven G., Paudel S., Emsellem E., Janz J., den Brok M., Gorgas J., Hensler G., Laurikainen E., Niemi S.M., R\'ys A., Salo H.
Publisher: Institute of Physics (IOP)
: McMaster University, 1280 Main Street West, GSB-118C, Hamilton, ON L8S 4K1
: 2014
Astrophysical Journal Supplement
: ApJS
: 215
: 2
: 16
: 66
: 51
: 0067-0049
: 0004-637X
DOI: https://doi.org/10.1088/0067-0049/215/2/17
: http://adsabs.harvard.edu/abs/2014ApJS..215...17T
 We present spatially resolved kinematics and global stellar
 populations and mass-to-light ratios for a sample of 39 dwarf
 early-type (dE) galaxies in the Virgo cluster studied as part of the
 SMAKCED stellar absorption-line spectroscopy and imaging survey. This
 sample is representative of the early-type population in the Virgo
 cluster in the absolute magnitude range -19.0 < Mr < -16.0 and of all
 morphological subclasses found in this galaxy population. For each dE,
 we measure the rotation curve and velocity dispersion profile and fit
 an analytic function to the rotation curve. We study the significance
 of the departure of the rotation curve from the best-fit analytic
 function (poorly fit) and of the difference between the approaching
 and receding sides of the rotation curve (asymmetry).  Our sample
 includes two dEs with kinematically decoupled cores that have been
 previously reported. We find that 62 â± 8% (23 out of the 39) of the
 dEs have a significant anomaly in their rotation curve. Analysis of
 the images reveals photometric anomalies for most galaxies. However,
 there is no clear correlation between the significance of the
 photometric and kinematic anomalies. We measure age-sensitive (H_beta and
 H_gammaA ) and metallicity sensitive (Fe4668 and Mgb) Lick spectral
 indices in the LIS-5 å system. This population of galaxies exhibits a
 wide range of ages and metallicities; we also find that 4 dEs show
 clear evidence of emission partially filling in the Balmer absorption
 lines. Finally, we estimate the total masses and dark matter fractions
 of the dEs and plot them in the mass-size, the mass-velocity
 dispersion, and the fundamental plane scaling relations. The dEs seem
 to be the bridge between massive early-type galaxies and dSphs, and
 have a median total mass within the Re of log Me = 9.1 ± 0.2 and a
 median dark matter fraction within the Re of fDM = 46 ± 18%. Any
 formation model for the dE galaxy class must account for this
 diversity of kinematic and photometric anomalies and stellar
 populations.
