scholarly journals Stellar Populations of Elliptical Galaxies in Virgo Cluster. I. The Data and Stellar Population Analysis

2006 ◽  
Vol 637 (1) ◽  
pp. 200-213 ◽  
Author(s):  
Y. Yamada ◽  
N. Arimoto ◽  
A. Vazdekis ◽  
R. F. Peletier
Keyword(s):  
Stellar Population ◽  
Population Analysis ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Virgo Cluster

scholarly journals Abundance Ratios in Dwarf Elliptical Galaxies

2016 ◽  
Vol 11 (S321) ◽  
pp. 269-269
Author(s):  
Seyda Sen ◽  
Reynier F. Peletier ◽  
Elisa Toloba ◽  
Jaco J. Mentz
Keyword(s):  
Star Formation ◽  
Stellar Population ◽  
Population Analysis ◽  
Elliptical Galaxies ◽  
Virgo Cluster ◽  
Scaling Relations ◽  
Unusual Behaviour ◽  
Dwarf Elliptical Galaxies ◽  
Index Index ◽  
Star Formation Histories

AbstractThe aim of this study is to determine abundance ratios and star formation histories (SFH) of dwarf ellipticals in the nearby Virgo cluster. We perform a stellar population analysis of 39 dEs and study them using index-index and scaling relations. We find an unusual behaviour where [Na/Fe] is under-abundant w.r.t. solar while [Ca/Fe] is over-abundant.

scholarly journals Dynamical masses of brightest cluster galaxies – II. Constraints on the stellar IMF

2020 ◽  
Vol 500 (3) ◽  
pp. 4153-4165
Author(s):  
S I Loubser ◽  
H Hoekstra ◽  
A Babul ◽  
Y M Bahé ◽  
M Donahue
Keyword(s):  
Gravitational Lensing ◽  
Stellar Population ◽  
Population Analysis ◽  
Stellar Populations ◽  
Stellar Mass ◽  
Initial Mass Function ◽  
Dynamical Mass ◽  
Cluster Galaxies ◽  
Brightest Cluster Galaxies ◽  
Mass Profiles

ABSTRACT We use stellar and dynamical mass profiles, combined with a stellar population analysis, of 32 brightest cluster galaxies (BCGs) at redshifts of 0.05 ≤$z$ ≤ 0.30, to place constraints on their stellar initial mass function (IMF). We measure the spatially resolved stellar population properties of the BCGs, and use it to derive their stellar mass-to-light ratios ($\Upsilon _{\star \rm POP}$). We find young stellar populations (<200 Myr) in the centres of 22 per cent of the sample, and constant $\Upsilon _{\star \rm POP}$ within 15 kpc for 60 per cent of the sample. We further use the stellar mass-to-light ratio from the dynamical mass profiles of the BCGs ($\Upsilon _{\star \rm DYN}$), modelled using a multi-Gaussian expansion and Jeans Anisotropic Method, with the dark matter contribution explicitly constrained from weak gravitational lensing measurements. We directly compare the stellar mass-to-light ratios derived from the two independent methods, $\Upsilon _{\star \rm POP}$ (assuming some IMF) to $\Upsilon _{\star \rm DYN}$ for the subsample of BCGs with no young stellar populations and constant $\Upsilon _{\star \rm POP}$. We find that for the majority of these BCGs, a Salpeter (or even more bottom-heavy) IMF is needed to reconcile the stellar population and dynamical modelling results although for a small number of BCGs, a Kroupa (or even lighter) IMF is preferred. For those BCGs better fit with a Salpeter IMF, we find that the mass-excess factor against velocity dispersion falls on an extrapolation (towards higher masses) of known literature correlations. We conclude that there is substantial scatter in the IMF amongst the highest mass galaxies.

scholarly journals Single metal-poor ultra compact dwarf galaxy at one kiloparsec distance from the low-mass elliptical galaxy FCC 47

2019 ◽  
Vol 625 ◽  
pp. A50 ◽  
Author(s):  
Katja Fahrion ◽  
Iskren Georgiev ◽  
Michael Hilker ◽  
Mariya Lyubenova ◽  
Glenn van de Ven ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Stellar Population ◽  
Dwarf Galaxy ◽  
Elliptical Galaxy ◽  
Population Analysis ◽  
Elliptical Galaxies ◽  
Star Cluster ◽  
High Mass ◽  
Low Metallicity ◽  
Low Mass

Context. Photometric surveys of galaxy clusters have revealed a large number of ultra compact dwarfs (UCDs) around predominantly massive elliptical galaxies. Their origin is still debated as some UCDs are considered to be the remnant nuclei of stripped dwarf galaxies while others seem to mark the high-mass end of the star cluster population. Aims. We aim to characterize the properties of a UCD found at very close projected distance (rwproj = 1.1 kpc) from the centre of the low-mass (M ∼ 1010 M⊙) early-type galaxy FCC 47. This is a serendipitous discovery from MUSE adaptive optics science verification data. We explore the potential origin of this UCD as either a massive cluster or the remnant nucleus of a dissolved galaxy. Methods. We used archival Hubble Space Telescope data to study the photometric and structural properties of FCC 47-UCD1. In the MUSE data, the UCD is unresolved, but we used its spectrum to determine the radial velocity and metallicity. Results. The surface brightness of FCC 47-UCD1 is best described by a single King profile with low concentration C = Rt/Rc ∼ 10 and large effective radius (reff = 24 pc). Its integrated magnitude and blue colour (Mg = −10.55 mag, (g − z) = 1.46 mag) combined with a metallicity of [M/H] = −1.12 ± 0.10 dex and an age > 8 Gyr obtained from the full fitting of the MUSE spectrum suggests a stellar population mass of M* = 4.87 × 106 M⊙. The low S/N of the MUSE spectrum prevents detailed stellar population analysis. Due to the limited spectral resolution of MUSE, we can only give an upper limit on the velocity dispersion (σ <  17 km s−1), and consequently on its dynamical mass (Mdyn <  1.3 × 107 M⊙). Conclusions. The origin of the UCD cannot be constrained with certainty. The low metallicity, old age, and magnitude are consistent with a star cluster origin, whereas the extended size is consistent with an origin as the stripped nucleus of a dwarf galaxy with a initial stellar mass of a few 108 M⊙.

scholarly journals Star formation history and isophotal shapes of fossil central galaxies

2007 ◽  
Vol 3 (S245) ◽  
pp. 81-82
Author(s):  
Habib G. Khosroshahi ◽  
Louisa A. Nolan
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Stellar Population ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Star Formation History ◽  
Spectral Fitting ◽  
Stellar Component ◽  
Formation History ◽  
Two Component

AbstractWe study the structure and stellar populations of the luminous elliptical galaxies dominating fossil groups and compare them with the brightest galaxies in ordinary groups. Despite being over-luminous, the fossil central galaxies do not show boxy stellar isophotes which are usually associated with luminous elliptical galaxies. Boxy isophotes, according to the numerical simulations, are produced in gas poor mergers. The isophotal shapes of the fossil central galaxies, therefore, suggest a gas rich merger for fossil central galaxies. Using a two-component spectral fitting, we show that the dominant stellar population of the fossil and non-fossil galaxies is old and the second population is either old or intermediate age. However, the second stellar component (recently-formed stars) in fossil central galaxies is significantly more metal poor than that in the brightest galaxies of non-fossil groups.

Kinematics and stellar populations of the double-barred early-type galaxy NGC357

2007 ◽  
Vol 3 (S245) ◽  
pp. 137-138
Author(s):  
Adriana de Lorenzo-Cáceres ◽  
Alexandre Vazdekis ◽  
J. Alfonso L. Aguerri
Keyword(s):  
Radial Velocity ◽  
Stellar Population ◽  
Velocity Dispersion ◽  
Population Analysis ◽  
Stellar Populations ◽  
Abundance Ratio ◽  
Complete Characterization ◽  
Early Type ◽  
Early Type Galaxy

AbstractWe have carried out a kinematical and stellar population analysis of the double-barred galaxy NGC357 to provide a more complete characterization of these systems and their role in the formation of galaxy bulges. We clearly identify the presence of the inner bar in the radial velocity and velocity dispersion profiles. The age, metallicity and [Mg/Fe] abundance ratio estimates are very similar to those of ellipticals of equivalent central σ. The [Mg/Fe] value for the bulge of this galaxy suggests formation timescales shorter than 1Gyr.

scholarly journals Near-IR Imaging of Elliptical Galaxies

1995 ◽  
Vol 164 ◽  
pp. 443-443 ◽  
Author(s):  
M.A. Pahre ◽  
S. Djorgovski ◽  
K. Matthews ◽  
D. Shupe ◽  
R. De Carvalho ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Stellar Population ◽  
Elliptical Galaxies ◽  
Virgo Cluster ◽  
Fundamental Plane ◽  
Near Ir ◽  
Surface Brightness Fluctuations ◽  
Distance Indicator ◽  
Color Gradients ◽  
Optical Color

We have imaged more than thirty early-type galaxies in the K-band to investigate their stellar populations. Our surface brightness fluctuations (SBF) measurements for the nearest 14 galaxies produce a mean fluctuations magnitude in the K-band of The scatter in the Virgo cluster is small at 0.18 mag, which implies that infrared SBF is potentially a good distance indicator (Pahre & Mould 1994). Inspection of the simple stellar population tracks of Worthey (1994) suggests that a plot of the fluctuation color against broadband color (V – I) might be useful in discriminating between age and metallicity effects in elliptical galaxies. We have measured (r – K) color gradients for the entire sample utilizing three methods, two of them independent of sky-subtraction errors, as found in Sparks & Jørgensen (1993). Our color gradients are consistent with a mean metallicity gradient of 0.14 mag dex−1, which is somewhat smaller than that implied by optical color and line gradients alone, suggesting that age gradients may also be important. Finally, we have constructed an infrared Fundamental Plane (FP) which is consistent with its optical counterpart; continued work will determine if there is a significant change in the tilt of the FP between the optical and infrared.

Stellar population analysis of galaxies in SDSS and LAMOST Pilot Survey

2013 ◽  
Vol 9 (S298) ◽  
pp. 399-399
Author(s):  
Xiaoyan Chen ◽  
Ali Luo ◽  
Haifeng Yang
Keyword(s):  
Stellar Population ◽  
Population Analysis ◽  
Stellar Populations ◽  
Optical Spectra ◽  
Pilot Survey ◽  
Flux Calibration ◽  
Spectra Fitting

AbstractThe Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, i.e. Guoshoujing Telescope) has finished its pilot survey (from October 2011 to June 2012). With about 3000 galaxy spectra collected during the pilot survey, we are planning to analyze the stellar populations of these galaxies in two different ways respectively. One is Lick indices (such as Hβ, Mgb, 〈Fe〉 etc., Worthey et al. 1994), which are not sensitive to the flux calibration, and another one is the full optical spectra fitting (Chen et al. 2009, 2010). Then we can evaluate the affects of flux calibration errors on stellar population analysis by comparing the results of the two methods′. Here we briefly show the early experiments aiming to test the consistency and/or difference between the two methods.

scholarly journals Hot Gaseous Halo in the Elliptical and Spiral Galaxies

1998 ◽  
Vol 188 ◽  
pp. 57-60
Author(s):  
H. Awaki
Keyword(s):  
Stellar Population ◽  
Spiral Galaxies ◽  
Massive Stars ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Starburst Galaxies ◽  
Physical Parameters ◽  
X Ray ◽  
Hot Gas ◽  
Gaseous Halo

The Einstein observations revealed that starburst and luminous elliptical galaxies had X-ray halo. These galaxies have quite different stellar population. Starburst galaxies contain young massive stars, while elliptical galaxies generally contain an old-metal rich population dominated by K and M giants. Therefore a question is why these two type of galaxies commonly have hot gas, in spite of quite different stellar populations. In order to address this question, we observed these galaxies with ASCA. In this paper, I would like to present observational results, then compare the physical parameters of the hot gas in these galaxies.

scholarly journals Stellar Populations in Dwarf Elliptical Galaxies

1996 ◽  
Vol 171 ◽  
pp. 382-382 ◽  
Author(s):  
J. Gorgas ◽  
S. Pedraz ◽  
N. Cardiel ◽  
J.J. Gonzalez
Keyword(s):  
Stellar Population ◽  
Line Strength ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Population Models ◽  
Wide Range ◽  
Central Regions ◽  
Single Burst ◽  
Dwarf Elliptical Galaxies ◽  
Measured Line

We present the results of a spectroscopic study in which we have measured line-strength indices in a sample of 5 dwarf and 2 compact elliptical galaxies (mostly from Virgo). Some conclusions about the stellar populations in dwarf E's are derived by comparing the sample with classical E galaxies. In the adjacent figure, we plot in the Hβ-[MgFe] plane the central indices of our sample of dwarf and compact E's together with data from González (1993, PhD Thesis). The grid represents the predictions of single-burst stellar population models from Worthey (1994, ApJS, 95, 107). The main conclusion is that, whilst the central regions of giant, intermediate and compact ellipticals span, according to stellar population models, a wide range in mean stellar ages, bright dwarf ellipticals are found to be old, compatible with a ∼ 10 Gyr old stellar population. This means that the dichotomy found in the Fundamental Plane between dwarf ellipticals and the gE-iE-cE sequence (Bender, Burstein & Faber 1992, ApJ, 399, 462) is also observed in the stellar populations.

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