2007AJ....133.1722E


Query : 2007AJ....133.1722E

2007AJ....133.1722E - Astron. J., 133, 1722-1740 (2007/April-0)

Internal properties of ultracompact dwarf galaxies in the Virgo cluster.

EVSTIGNEEVA E.A., GREGG M.D., DRINKWATER M.J. and HILKER M.

Abstract (from CDS):

We present new imaging and spectroscopic observations of six ultracompact dwarf (UCD) galaxies in the Virgo Cluster, along with reanalyzed data for five Fornax Cluster UCDs. These are the most luminous UCDs: -14 mag<MV←12 mag. Our Hubble Space Telescope imaging shows that most of the UCDs have shallow or steep cusps in their cores; only one UCD has a flat ``King'' core. None of the UCDs show tidal cutoffs down to our limiting surface brightness. Spectroscopic analysis shows that Virgo UCDs are old (older than 8 Gyr) and have metallicities in the range from [Z/H]=-1.35 to +0.35 dex. Five Virgo UCDs have supersolar [α/Fe] abundance ratios, and one Virgo UCD has a solar abundance ratio. The supersolar [α/Fe] abundances are typical of old stellar populations found in globular clusters and elliptical galaxies. We find that Virgo UCDs have structural and dynamical properties similar to Fornax UCDs. The Virgo and Fornax UCDs all have masses ~(2-9)x107 M and mass-to-light ratios ~(3-5) M/L☉,V. The dynamical mass-to-light ratios for Virgo UCDs are consistent with simple stellar population model predictions: the Virgo UCDs do not require dark matter to explain their mass-to-light ratios. We conclude that the internal properties of Virgo UCDs are consistent with them being the high-mass/high-luminosity extreme of known globular cluster populations. We refrain from any firm conclusions on Fornax UCD origins until accurate age, metallicity, and α-abundance estimates are obtained for them. Some of our results, notably the fundamental plane projections, are consistent with the formation of UCDs by the simple removal of the halo from the nuclei of nucleated dwarf galaxies. However, the ages, metallicities, and abundances for Virgo UCDs are not consistent with this simple stripping model. It might be consistent with more sophisticated models of the stripping process that include the effects of gas removal on the chemical evolution of the nuclei.

Abstract Copyright:

Journal keyword(s): Galaxies: Abundances - Galaxies: Dwarf - Galaxies: Formation - Galaxies: Kinematics and Dynamics - Galaxies: Star Clusters - Galaxies: Structure

CDS comments: Objets VUCD (in Virgo) = [JDJ2006] , UCD (in Fornax) = [DJG2000] UCO

Simbad objects: 47

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Number of rows : 47
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 NAME Mayall II GlC 00 32 46.53 +39 34 40.5   14.564 13.807 13.208 12.684 ~ 381 1
2 M 32 IG 00 42 41.825 +40 51 54.61 9.51 9.03 8.08     ~ 2060 2
3 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11533 1
4 NAME SMC G 00 52 38.0 -72 48 01   2.79 2.2     ~ 9987 1
5 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 6076 1
6 [GMK2001] 114 GlC 03 22 42.4375 -37 12 41.516   19.63 18.46     ~ 22 1
7 [BAL2007] uc257.5 GiC 03 37 03.2448984794 -35 38 04.392833667   19.85 19.31     ~ 32 1
8 NAME UCD-FORS 81 GlC 03 38 06.3039061784 -35 28 58.553454257   18.85 19.31 18.80 18.18 ~ 38 1
9 NGC 1399 BiC 03 38 29.083 -35 27 02.67 11.05 9.74 9.59 8.12   ~ 1490 1
10 ACO S 373 ClG 03 38 30 -35 27.3           ~ 1647 0
11 2MASS J03385407-3533331 GiC 03 38 54.0548295896 -35 33 33.352307509   18.5 18.06     ~ 69 0
12 LEDA 2793608 GiC 03 39 35.9213136977 -35 28 24.471994346   18.82 19.12     ~ 43 1
13 [DJG2000] UCO 5 GiC 03 39 52.5447956746 -35 04 24.032437250   19.66 19.50     ~ 34 0
14 2MASX J03451407-3656123 GiC 03 45 14.0931638772 -36 56 12.022631568   15.32       ~ 51 0
15 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15660 1
16 HD 40460 PM* 06 00 06.0385647008 +27 16 19.871506773   7.651 6.617     K1III 84 0
17 * 30 Gem PM* 06 43 59.2869703486 +13 13 40.818795627 6.82 5.65 4.49 3.63 3.03 K0+IIICa1 137 0
18 Feige 34 HS* 10 39 36.7377085527 +43 06 09.209752646 9.613 10.91 11.14 11.319 11.464 sdOp 629 0
19 IC 3170 G 12 20 26.547 +09 25 27.40   15.0       ~ 16 0
20 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 6126 0
21 M 49 Sy2 12 29 46.798 +08 00 01.48   13.21 12.17     ~ 2002 2
22 NGVS J123007.57+123631.0 GlC 12 30 07.5690843498 +12 36 30.996360221           ~ 25 0
23 UGCA 283 GiG 12 30 31.985 +12 29 24.85   14.5       ~ 393 0
24 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6522 3
25 [JDJ2006] 3 G 12 30 57.3833546242 +12 25 44.499140903   19.32 17.97     ~ 45 0
26 NGVS J123101.47+121924.5 LSB 12 31 01.4778575124 +12 19 24.597519380     19.33     ~ 24 0
27 [JDJ2006] 4 GlC 12 31 04.4757913483 +11 56 36.488486778           ~ 22 0
28 [JDJ2006] 5 GlC 12 31 11.8766910181 +12 41 01.081447941           ~ 27 0
29 NGVS J123128.36+122503.6 GlC 12 31 28.3597374413 +12 25 03.599290701           ~ 23 0
30 2MASS J12315289+1215589 G 12 31 52.8978463348 +12 15 59.053574946           ~ 43 0
31 IC 3461 GiG 12 32 02.747 +11 53 23.16   15.4 14.88   13.3 ~ 119 0
32 ACO 1689 ClG 13 11 29.5 -01 20 28           ~ 1053 0
33 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 4147 3
34 NGC 5139 GlC 13 26 47.28 -47 28 46.1   6.12 5.33     ~ 3154 0
35 HD 137704 PM* 15 26 17.3840641932 +34 20 09.579848892   6.873 5.450     K4III 83 0
36 * tet UMi V* 15 31 24.9159906558 +77 20 57.711998802   6.535 4.982     K5-IIICN0.5 113 0
37 * 16 Ser SB* 15 36 29.5749786777 +10 00 36.557426427   6.217 5.253     K0III:CN1Ba0.7Sr2 200 0
38 * ome Ser PM* 15 50 17.5464926986 +02 11 47.439052415   6.236 5.217     K0IV 123 1
39 V* QY Ser LP* 15 54 34.6123081346 +20 18 39.491051719 8.98 7.03 5.44 4.18 3.21 K8IIIb 87 0
40 * eps CrB PM* 15 57 35.2514673 +26 52 40.363564 6.650 5.360 4.130 3.27 2.64 K2IIIab 251 1
41 HD 145148 PM* 16 09 11.2152519637 +06 22 43.291224462   6.97   5.3   K1.5IV 167 0
42 * 14 Her PM* 16 10 24.3152754550 +43 49 03.498734567   7.57   6.1   K0V 422 1
43 * ksi CrB ** 16 22 05.8235660072 +30 53 31.175905159   5.833 4.849     G9IIIFe-0.5 123 0
44 HD 148513 PM* 16 28 33.9805980948 +00 39 53.998682880 8.65 6.85 5.39     K3V 156 0
45 * h Her PM* 16 32 36.2919015 +11 29 16.947932 8.16 6.34 4.85 3.65 2.79 K4.5III 149 0
46 [WSL93] 3 GlC 22 20 43.878 -24 40 37.87     17.86     ~ 50 0
47 [MWS97] 30 Cl* 22 20 45.33 -24 40 49.5   19.87 19.46     ~ 12 1

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2021.11.30-18:36:22

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