Embedded disks in Fornax dwarf elliptical galaxies

Rijcke, S. De; Dejonghe, Herwig; Zeilinger, W. W.; Hau, G. K. T.

doi:10.1051/0004-6361:20021866

Cited by 99 publications

(110 citation statements)

References 19 publications

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“…The dEs formed in these simulations rotate quite rapidly and some still display some memory of their former state. Examples are dEs with embedded stellar disks (Barazza et al 2002;De Rijcke et al 2003a; or kinematically decoupled cores . This model explicitly takes into account that dEs are found predominantly in clusters and groups of galaxies.…”

Section: The Harassment Scenariomentioning

confidence: 99%

Formation and evolution of dwarf elliptical galaxies

Rijcke¹,

Michielsen²,

Dejonghe³

et al. 2005

A&A

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117

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Abstract. This paper is the first in a series in which we present the results of an ESO Large Program on the kinematics and internal dynamics of dwarf elliptical galaxies (dEs). We obtained deep major and minor axis spectra of 15 dEs and broad-band imaging of 22 dEs. Here, we investigate the relations between the parameters that quantify the structure (B-band luminosity L B , half-light radius R e , and mean surface brightness within the half-light radius I e = L B /2πR 2 e ) and internal dynamics (velocity dispersion σ) of dEs. We confront predictions of the currently popular theories for dE formation and evolution with the observed position of dEs in log L B vs. log σ, log L B vs. log R e , log L B vs. log I e , and log R e vs. log I e diagrams and in the (log σ, log R e , log I e ) parameter space in which bright and intermediate-luminosity elliptical galaxies and bulges of spirals define a Fundamental Plane (FP). In order to achieve statistical significance and to cover a parameter interval that is large enough for reliable inferences to be made, we merge the data set presented in this paper with two other recently published, equally large data sets. We show that the dE sequences in the various univariate diagrams are disjunct from those traced by bright and intermediateluminosity elliptical galaxies and bulges of spirals. It appears that semi-analytical models (SAMs) that incorporate quiescent star formation with an essentially z-independent star-formation efficiency, combined with post-merger starbursts and the dynamical response after supernova-driven gas-loss, are able to reproduce the position of the dEs in the various univariate diagrams. SAMs with star-formation efficiencies that rise as a function of redshift are excluded since they leave the observed sequences traced by dEs virtually unpopulated. dEs tend to lie above the FP and the FP residual declines as a function of luminosity. Again, models that take into account the response after supernova-driven mass-loss correctly predict the position of dEs in the (log σ, log R e , log I e ) parameter space as well as the trend of the FP residual as a function of luminosity. While these findings are clearly a success for the hierarchical-merging picture of galaxy formation, they do not necessarily invalidate the alternative "harassment" scenario, which posits that dEs stem from perturbed and stripped late-type disk galaxies that entered clusters and groups of galaxies about 5 Gyr ago.

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Section: The Harassment Scenariomentioning

confidence: 99%

Formation and evolution of dwarf elliptical galaxies

Rijcke¹,

Michielsen²,

Dejonghe³

et al. 2005

A&A

Self Cite

117

123

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show abstract

“…Some dEs might still contain a memory of their former state. Examples are dEs with embedded stellar disks, bars, and spiral structure (Barazza et al 2002;De Rijcke et al 2003a;Graham et al 2003) and with sizable amounts of warm gas, suggesting recent star formation in some dEs (De Rijcke et al 2003b;Michielsen et al 2004). Moreover, rotationally flattened dEs have been discovered (De Rijcke et al 2001;Simien & Prugniel 2002).…”

Section: Postdoctoral Fellow Of the Fund For Scientific Research -Flamentioning

confidence: 99%

Dwarf elliptical galaxies with kinematically decoupled cores

Rijcke

Dejonghe

Zeilinger³

et al. 2004

A&A

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Abstract. We present, for the first time, photometric and kinematical evidence, obtained with FORS2 on the VLT, for the existence of kinematically decoupled cores (KDCs) in two dwarf elliptical galaxies; FS76 in the NGC 5044 group and FS373 in the NGC 3258 group. Both kinematically peculiar subcomponents rotate in the same sense as the main body of their host galaxy but betray their presence by a pronounced bump in the rotation velocity profiles at a radius of about 1 . The KDC in FS76 rotates at 10 ± 3 km s −1 , with the host galaxy rotating at 15 ± 6 km s −1 ; the KDC in FS373 has a rotation velocity of 6 ± 2 km s −1 while the galaxy itself rotates at 20 ± 5 km s −1 . FS373 has a very complex rotation velocity profile with the velocity changing sign at 1.5 R e . The velocity and velocity dispersion profiles of FS76 are asymmetric at larger radii. This could be caused by a past gravitational interaction with the giant elliptical NGC 5044, which is at a projected distance of 50 kpc. We argue that these decoupled cores are most likely not produced by mergers in a group or cluster environment because of the prohibitively large relative velocities. A plausible alternative is offered by flyby interactions between a dwarf elliptical or its disky progenitor and a massive galaxy. The tidal forces during an interaction at the relative velocities and impact parameters typical for a group environment exert a torque on the dwarf galaxy that, according to analytical estimates, transfers enough angular momentum to its stellar envelope to explain the observed peculiar kinematics.

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“…This makes the morphological classification strongly dependent on the data quality, depth, and resolution. Therefore, it is not surprising that, as better data becomes available, many galaxies formerly classified as dEs show a substantial amount of substructure in the form of spiral arms, disks, and/or irregular features (Jerjen et al 2000;Barazza et al 2002;De Rijcke et al 2003;Geha et al 2003;Graham & Guzmán 2003;Ferrarese et al 2006;Lisker et al 2006aLisker et al , 2006bLisker et al , 2007Janz et al 2012Janz et al , 2014.…”

Section: Introductionmentioning

confidence: 99%

The Next Generation Virgo Cluster Survey Xvi: The Angular Momentum of Dwarf Early-Type Galaxies From Globular Cluster Satellites

Toloba

Guhathakurta

et al. 2016

ApJ

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We analyze the kinematics of six Virgo cluster dwarf early-type galaxies (dEs) from their globular cluster (GC) systems. We present new Keck/DEIMOS spectroscopy for three of them and re-analyze the data found in the literature for the remaining three. We use two independent methods to estimate the rotation amplitude (V rot ) and velocity dispersion (σ GC ) of the GC systems and evaluate their statistical significance by simulating non-rotating GC systems with the same number of GC satellites and velocity uncertainties. Our measured kinematics agree with the published values for the three galaxies from the literature and, in all cases, some rotation is measured. However, our simulations show that the null hypothesis of being non-rotating GC systems cannot be ruled out. In the case of VCC1861, the measured V rot and the simulations indicate that it is not rotating. In the case of VCC1528, the null hypothesis can be marginally ruled out, and thus it might be rotating although further confirmation is needed. In our analysis, we find that, in general, the measured V rot tends to be overestimated and the measured σ GC tends to be underestimated by amounts that depend on the intrinsic V rot /σ GC , the number of observed GCs (N GC ), and the velocity uncertainties. The bias is negligible when N GC  20. In those cases where a large N GC is not available, it is imperative to obtain data with small velocity uncertainties. For instance, errors of 2 km s −1 lead to V rot < 10 km s −1 for a system that is intrinsically not rotating.

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Embedded disks in Fornax dwarf elliptical galaxies

Cited by 99 publications

References 19 publications

Formation and evolution of dwarf elliptical galaxies

Formation and evolution of dwarf elliptical galaxies

Dwarf elliptical galaxies with kinematically decoupled cores

The Next Generation Virgo Cluster Survey Xvi: The Angular Momentum of Dwarf Early-Type Galaxies From Globular Cluster Satellites

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