2007A&A...463..119H


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.25CET08:13:34

2007A&A...463..119H - Astronomy and Astrophysics, volume 463, 119-130 (2007/2-3)

Dynamical masses of ultra-compact dwarf galaxies in Fornax.

HILKER M., BAUMGARDT H., INFANTE L., DRINKWATER M., EVSTIGNEEVA E. and GREGG M.

Abstract (from CDS):

We determine masses and mass-to-light ratios of five ultra-compact dwarf galaxies (UCDs) and one dwarf elliptical nucleus in the Fornax cluster from high resolution spectroscopy. We examine whether they are consistent with pure stellar populations or whether dark matter is needed to explain their masses. Velocity dispersions were derived from selected wavelength regions using a direct-fitting method. To estimate the masses of the UCDs a new modelling program has been developed that allows a choice of different representations of the surface brightness profile (i.e. Nuker, Sersic or King laws) and corrects the observed velocity dispersions for observational parameters (i.e. seeing, slit size). The derived dynamical masses are compared to those expected from stellar population models. The observed velocity dispersions range between 22 and 30km/s. The resulting masses are between 1.8 and 9.5x107M. These, as well as the central and global projected velocity dispersions, were derived from the generalized King model which turned out to give the most stable results. The masses of two UCDs, that are best fitted by a two-component profile, were derived from a combined King+Sersic model. The mass-to-light ratios of the Fornax UCDs range between 3 and 5(M/LV). The M/LV ratio of the dwarf elliptical nucleus is 2.5. These values are compatible with predictions from stellar population models. Within 1-2 half-mass radii dark matter is not dominating UCDs and the nucleus. An increasing dark matter contribution towards larger radii can not be ruled out with the present data. The M/LV ratios of some UCDs suggest they have intermediate age stellar populations. We show that the mass-to-light ratios of UCDs in Fornax are consistent with those expected for pure stellar populations. Thus UCDs seem to be the result of cluster formation processes within galaxies rather than being compact dark matter dominated substructures themselves. Whether UCDs gained their mass in super-star cluster complexes of mergers or in nuclear star cluster formation processes remains an open question. It appears, however, clear that star clusters more massive than about 5x106M exhibit a more complex formation history than the less massive ``ordinary'' globular clusters.

Abstract Copyright:

Journal keyword(s): galaxies: clusters: individual: Fornax cluster - galaxies: star clusters - galaxies: dwarf - galaxies: kinematics and dynamics

CDS comments: Paragraph 5. NGC 7252:W3 is [WSL93] 3 in Simbad, NGC 7252:W30 is [MWS97] 30, NGC 1316:G114 is [GMK2001] 114.

Simbad objects: 29

goto Full paper

goto View the reference in ADS

Number of rows : 29

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 NAME Mayall II GlC 00 32 46.53 +39 34 40.5   14.564 13.807 13.208 12.684 ~ 372 1
2 M 32 IG 00 42 41.825 +40 51 54.61 9.51 9.03 8.08     ~ 2025 2
3 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11090 1
4 * 25 Cet PM* 01 03 02.5375845545 -04 50 11.758232770   6.517 5.408     K0/1III 63 0
5 HD 9051 PM* 01 28 46.5026523997 -24 20 25.443519152   9.73 8.92     G6/8IIIwF5 52 0
6 HD 17233 PM* 02 43 52.1004945707 -54 47 27.538466815   9.81 9.04     G8wG0IV/V 25 0
7 HD 20038 * 03 10 26.7853051574 -58 49 40.568893775 10.16 9.74 8.91     F7wG6III 40 0
8 HD 21022 Pe* 03 22 21.6078258078 -32 59 40.003034166   10.09 9.20     G6/8(V)w 43 0
9 [GMK2001] 114 GlC 03 22 42.4375 -37 12 41.516   19.63 18.46     ~ 21 1
10 [BAL2007] uc257.5 GiC 03 37 03.2448984794 -35 38 04.392833667   19.85 19.31     ~ 32 1
11 NAME UCD-FORS 81 GlC 03 38 06.3039061784 -35 28 58.553454257   18.85 19.31 18.80 18.18 ~ 38 1
12 ACO S 373 ClG 03 38 30 -35 27.3           ~ 1573 0
13 2MASS J03385407-3533331 GiC 03 38 54.0548295896 -35 33 33.352307509   18.5 18.06     ~ 69 0
14 LEDA 2793608 GiC 03 39 35.9213136977 -35 28 24.471994346   18.82 19.12     ~ 43 1
15 [DJG2000] UCO 5 GiC 03 39 52.5447956746 -35 04 24.032437250   19.66 19.50     ~ 34 0
16 2MASX J03451407-3656123 GiC 03 45 14.0931638772 -36 56 12.022631568   15.32       ~ 50 0
17 HD 41667 PM* 06 05 03.6442370627 -32 59 38.725804168   9.49 8.52     G8V 38 0
18 NGC 4038 GiP 12 01 53.002 -18 52 03.32   10.91   9.74 11.0 ~ 1281 1
19 NAME Antennae IG 12 01 53.170 -18 52 37.92           ~ 1566 0
20 NGC 4039 GiP 12 01 53.8 -18 53 06   11.08   9.77   ~ 1134 1
21 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5925 0
22 [JDJ2006] 3 G 12 30 57.3833546242 +12 25 44.499140903   19.32 17.97     ~ 44 0
23 NGVS J123101.47+121924.5 G 12 31 01.4778575124 +12 19 24.597519380     19.33     ~ 23 0
24 [JDJ2006] 5 GlC 12 31 11.8766910181 +12 41 01.081447941           ~ 27 0
25 NGVS J123128.36+122503.6 GlC 12 31 28.3597374413 +12 25 03.599290701           ~ 22 0
26 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4039 3
27 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3037 0
28 [WSL93] 3 GlC 22 20 43.878 -24 40 37.87     17.86     ~ 50 0
29 [MWS97] 30 Cl* 22 20 45.33 -24 40 49.5   19.87 19.46     ~ 12 1

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2007A&A...463..119H and select 'bookmark this link' or equivalent in the popup menu


2020.11.25-08:13:34

© Université de Strasbourg/CNRS

    • Contact