A1 Refereed original research article in a scientific journal

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




AuthorsToloba 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.

PublisherInstitute of Physics (IOP)

Publishing placeMcMaster University, 1280 Main Street West, GSB-118C, Hamilton, ON L8S 4K1

Publication year2014

JournalAstrophysical Journal Supplement

Journal acronymApJS

Volume215

Issue2

First page 16

Last page66

Number of pages51

ISSN0067-0049

eISSN0004-637X

DOIhttps://doi.org/10.1088/0067-0049/215/2/17

Web address http://adsabs.harvard.edu/abs/2014ApJS..215...17T


Abstract

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.



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