Kinematics and stellar populations of the dwarf elliptical galaxy IC 3653

Context. Globular clusters are representative of the oldest stellar populations. It is thus essential to have a complete census of these systems in dwarf galaxies, from which more massive galaxies are progressively formed in the hierarchical scenario. Aims. We present the results of spectroscopic observations of eight globular cluster candidates in NGC 147, a satellite dwarf elliptical galaxy of M 31. Our goal is to make a complete inventory of the globular cluster system of this galaxy, determine the properties of their stellar populations, and compare these properties with those of systems of globular clusters in other dwarf galaxies. Methods. The candidates were identified on Canada-France-Hawaii telescope photographic plates. Medium resolution spectra were obtained with the SCORPIO spectrograph at the prime focus of the 6 m telescope of the Russian Academy of Sciences. They were analyzed using predictions of stellar population synthesis models. Results. We were able to confirm the nature of all eight candidates, three of which (GC5, GC7, and GC10) are indeed globular clusters, and to estimate evolutionary parameters for the two brightest ones and for Hodge II. The bright clusters GC5 and GC7 appear to have metallicities ([Z/H] ∼ −1.5 ÷ −1.8) that are lower than the oldest stars in the galaxy. The fainter GC Hodge II has a metallicity [Z/H] = −1.1, similar to that of the oldest stars in the galaxy. The clusters GC5 and GC7 have low alpha-element abundance ratios. The mean age of the globular clusters in NGC 147 is 9 ± 1 Gyr. We also measured the radial velocities of Hodge II and IV, and derived a mass of NGC 147 in good agreement with the value from the literature. The frequency, S n = 6.4, and mass fraction, T = 14 of globular clusters in NGC 147 appear to be higher than those for NGC 185 and 205. Conclusions. Our results indicate that the bright clusters GC5, GC7, and Hodge III formed in the main star-forming period ∼8−10 Gyr ago, while the fainter clusters Hodge I and II formed together with the second generation of field stars.

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“…This approach is a simplification of methods used for modeling the spectral evolution of galaxies (Chilingarian 2007;Koleva et al 2008).…”

Section: Continuum Shape Fittingmentioning

confidence: 99%

Globular cluster content and evolutionary history of NGC 147

Шарина

Davoust

2009

A&A

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“…One extreme example is the kinematically decoupled core found in some massive, early-type galaxies (e.g., Krajnović et al 2011) and in a few low-mass, early-type galaxies (e.g., Thomas et al 2006;Chilingarian et al 2007;Toloba et al 2014b, Gérou et al, 2015. These could be remnants of galaxy mergers or gas accretion, and are thus good indicators of the formation history of the galaxy.…”

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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“…Recent discoveries of spiral arms, bars, and disks in several dEs and dS0s (Jerjen et al 2000;Barazza et al 2002;Graham et al 2003;De Rijcke et al 2003Chilingarian et al 2007;Lisker et al 2007) have put a new twist on the debate on these objects' origin. It has been proposed that different formation mechanisms and progenitors were required to account for the diversity of the characteristics of the early-type dwarfs (nucleation, flattening, rotation, etc.)…”

Section: Introductionmentioning

confidence: 99%

Stellar population and kinematics of NGC 404

Bouchard

Prugniel

Koleva

et al. 2010

A&A

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Context. NGC 404 is a nearly face-on, nearby low-luminosity lenticular galaxy. Probing its characteristics provides a wealth of information on the details of the possible evolution processes of dS0 galaxies, which may not be possible in other, more distant objects. Aims. We study the internal kinematics and the spatial distribution of the star formation history in NGC 404. Methods. We obtained long-slit spectroscopy at the OHP 1m93 telescope along the major and minor axes of NGC 404. The spectra had a resolution R = 3600 covering a wavelength range from 4600 to 5500 Å. The data were fitted against the Pegase. HR stellar population models to derive the internal stellar kinematics, ages, and metallicities simultaneously. All this was done while taking any instrumental contamination to the line-of-sight velocity distribution into account. First, the global properties of the galaxy were analysed by fitting a single model to the data and looking at the kinematic variations and SSP equivalent age and metallicities as a function of radius. Afterwards, the stellar populations were decomposed into 4 individually analysed components.Results. NGC 404 clearly shows two radial velocity inversions along its major axis. The kinematically decoupled core rotates in the same direction as the neutral hydrogen shell that surrounds the galaxy. We resolved the star formation history in the core of the galaxy into 4 events Conclusions. We conclude that NGC 404 had a spiral morphology about 1 Gyr ago and that one or many merger events has triggered a morphological transition. The interstellar medium in the galaxy has two components, the cold molecular gas is most probably a remnant from its past spiral incarnation and the outer neutral hydrogen layer that has probably been acquired in one of the latest mergers.

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Kinematics and stellar populations of the dwarf elliptical galaxy IC 3653

Cited by 84 publications

References 63 publications

Globular cluster content and evolutionary history of NGC 147

Globular cluster content and evolutionary history of NGC 147

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

Stellar population and kinematics of NGC 404

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