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. F.,Boselli, A.,Lisker, T.,Falcó,n-Barroso, J.,Simon, J. D.,van de Ven, G.,Paudel, S.,Emsellem, E.,Janz, J.,den Brok, M.,Gorgas, J.,Hensler, G.,Laurikaine IOP Publishing 2014 The Astrophysical journal Supplement series Vol.215 No.2

<P>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 < M-r < -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 +/- 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-gamma A) and metallicity sensitive (Fe4668 and Mgb) Lick spectral indices in the LIS-5 angstrom 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, themass-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 R-e of logM(e) = 9.1 +/- 0.2 and a median dark matter fraction within the R-e of f(DM) = 46 +/- 18%. Any formation model for the dE galaxy class must account for this diversity of kinematic and photometric anomalies and stellar populations.</P>

The SAURON project – XIX. Optical and near‐infrared scaling relations of nearby elliptical, lenticular and Sa galaxies

Falcó,n‐,Barroso, J.,van de Ven, G.,Peletier, R. F.,Bureau, M.,Jeong, H.,Bacon, R.,Cappellari, M.,Davies, R. L.,de Zeeuw, P. T.,Emsellem, E.,Krajnović,, D.,Kuntschner, H.,McDermid, R. Blackwell Publishing Ltd 2011 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.417 No.3

<P><B>ABSTRACT</B></P><P>We present ground‐based MDM Observatory <I>V</I>‐band and <I>Spitzer</I>/InfraRed Array Camera 3.6‐<IMG src='/wiley-blackwell_img/equation/MNR_19372_mu1.gif' alt ='inline image'/>m‐band photometric observations of the 72 representative galaxies of the SAURON survey. Galaxies in our sample probe the elliptical E, lenticular S0 and spiral Sa populations in the nearby Universe, both in field and cluster environments. We perform aperture photometry to derive homogeneous structural quantities. In combination with the SAURON stellar velocity dispersion measured within an effective radius (σ<SUB>e</SUB>), this allows us to explore the location of our galaxies in the colour–magnitude, colour–σ<SUB>e</SUB>, Kormendy, Faber–Jackson and Fundamental Plane scaling relations. We investigate the dependence of these relations on our recent kinematical classification of early‐type galaxies (i.e. slow/fast rotators) and the stellar populations. Slow rotator and fast rotator E/S0 galaxies do not populate distinct locations in the scaling relations, although slow rotators display a smaller intrinsic scatter. We find that Sa galaxies deviate from the colour–magnitude and colour–σ<SUB>e</SUB> relations due to the presence of dust, while the E/S0 galaxies define tight relations. Surprisingly, extremely young objects do not display the bluest (<I>V</I>−[3.6]) colours in our sample, as is usually the case in optical colours. This can be understood in the context of the large contribution of thermally pulsing asymptotic giant branch stars to the infrared, even for young populations, resulting in a very tight (<I>V</I>−[3.6])–σ<SUB>e</SUB> relation that in turn allows us to define a strong correlation between metallicity and σ<SUB>e</SUB>. Many Sa galaxies appear to follow the Fundamental Plane defined by E/S0 galaxies. Galaxies that appear offset from the relations correspond mostly to objects with extremely young populations, with signs of ongoing, extended star formation. We correct for this effect in the Fundamental Plane, by replacing luminosity with stellar mass using an estimate of the stellar mass‐to‐light ratio, so that all galaxies are part of a tight, single relation. The new estimated coefficients are consistent in both photometric bands and suggest that differences in stellar populations account for about half of the observed tilt with respect to the virial prediction. After these corrections, the slow rotator family shows almost no intrinsic scatter around the best‐fitting Fundamental Plane. The use of a velocity dispersion within a small aperture (e.g. <I>R</I><SUB>e</SUB>/8) in the Fundamental Plane results in an increase of around 15 per cent in the intrinsic scatter and an average 10 per cent decrease in the tilt away from the virial relation.</P>

The SAURON project – XIII. SAURON–GALEX study of early-type galaxies: the ultraviolet colour–magnitude relations and Fundamental Planes

Jeong, Hyunjin,Yi, Sukyoung K.,Bureau, Martin,Davies, Roger L.,Falcó,n-Barroso, Jesú,s,van de Ven, Glenn,Peletier, Reynier F.,Bacon, Roland,Cappellari, Michele,de Zeeuw, Tim,Emsellem, Eric Blackwell Publishing Ltd 2009 Monthly notices of the Royal Astronomical Society Vol.398 No.4

<P>ABSTRACT</P><P>We present <I>Galaxy Evolution Explorer</I> far-ultraviolet (FUV) and near-ultraviolet (NUV) imaging of 34 nearby early-type galaxies from the SAURON representative sample of 48 E/S0 galaxies, all of which have ground-based optical imaging from the MDM Observatory. The surface brightness profiles of nine galaxies (≈26 per cent) show regions with blue UV−optical colours suggesting RSF. Five of these (≈15 per cent) show blue integrated UV–optical colours that set them aside in the NUV integrated colour–magnitude relation. These are objects with either exceptionally intense and localized NUV fluxes or blue UV−optical colours throughout. They also have other properties confirming they have had RSF, in particular Hβ absorption higher than expected for a quiescent population and a higher CO detection rate. This suggests that residual star formation is more common in early-type galaxies than we are used to believe. NUV blue galaxies are generally drawn from the lower stellar velocity dispersion (σ<SUB>e</SUB> < 200 km s<SUP>−1</SUP>) and thus lower dynamical mass part of the sample. We have also constructed the first UV Fundamental Planes and show that NUV blue galaxies bias the slopes and increase the scatters. If they are eliminated, the fits get closer to expectations from the virial theorem. Although our analysis is based on a limited sample, it seems that a dominant fraction of the tilt and scatter of the UV Fundamental Planes is due to the presence of young stars in preferentially low-mass early-type galaxies. Interestingly, the UV–optical radial colour profiles reveal a variety of behaviours, with many galaxies showing signs of RSF, a central UV-upturn phenomenon, smooth but large-scale age and metallicity gradients and in many cases a combination of these. In addition, FUV−NUV and FUV−<I>V</I> colours even bluer than those normally associated with UV-upturn galaxies are observed at the centre of some quiescent galaxies. Four out of the five UV-upturn galaxies are slow rotators. These objects should thus pose interesting challenges to stellar evolutionary models of the UV upturn.</P>