2010A&A...516A..85C


Query : 2010A&A...516A..85C

2010A&A...516A..85C - Astronomy and Astrophysics, volume 516, A85-85 (2010/6-3)

A close look at the Centaurus A group of galaxies. I. Metallicity distribution functions and population gradients in early-type dwarfs.

CRNOJEVIC D., GREBEL E.K. and KOCH A.

Abstract (from CDS):

We study dwarf galaxies in the Centaurus A group to investigate their metallicity and possible environmental effects. The Centaurus A group (at ∼4Mpc from the Milky Way) contains about 50 known dwarf companions of different morphologies and stellar contents, thus making it a very interesting target to study how these galaxies evolve.Here we present results for the early-type dwarf galaxy population in this group. We used archival HST/ACS data to study the resolved stellar content of 6 galaxies, together with isochrones from the Dartmouth stellar evolutionary models.We derive photometric metallicity distribution functions of stars on the upper red giant branch via isochrone interpolation. The 6 galaxies are moderately metal-poor (<[Fe/H]≥-1.56 to -1.08), and metallicity spreads are observed (internal dispersions of σ[Fe/H]=0.10-0.41dex). We also investigate whether intermediate-age stars are present, and discuss how these affect our results. The dwarfs exhibit flat to weak radial metallicity gradients. For the two most luminous, most metal-rich galaxies, we find statistically significant evidence of at least two stellar subpopulations: the more metal-rich stars are found in the center of the galaxies, while the metal-poor ones are more broadly distributed within the galaxies.We find no clear trend in the derived physical properties as a function of (present-day) galaxy position in the group, which may come from the small sample we investigate. We compare our results to the early-type dwarf population of the Local Group, and find no outstanding differences, even though the Centaurus A group is a denser environment that is possibly in a more advanced dynamical stage.

Abstract Copyright:

Journal keyword(s): galaxies: dwarf - galaxies: evolution - galaxies: photometry - galaxies: groups: individual: Cen A group - galaxies: stellar content

Simbad objects: 23

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Number of rows : 23
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 NGC 147 GiG 00 33 12.120 +48 30 31.46   12.0 9.5     ~ 668 1
2 NGC 185 Sy2 00 38 57.9400026024 +48 20 15.035874648   9.10 9.2     ~ 778 1
3 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 12109 1
4 NAME Scl Group GrG 01 00 06 -33 44.2           ~ 496 0
5 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1270 4
6 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1660 1
7 NAME Carina dSph G 06 41 36.7 -50 57 58   22.14 11.0 19.47   ~ 1076 0
8 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1151 1
9 NAME Dwarf Elliptical Galaxy in Sex G 10 13 02.9 -01 36 53   12 10.4     ~ 796 0
10 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 804 0
11 NAME CVn I Group GrG 12 32 48.3 +33 57 07           ~ 139 0
12 LEDA 166158 G 13 12 45.2 -41 49 57   19.3       ~ 35 0
13 ESO 269-66 GiC 13 13 09.2 -44 53 23   14.14       ~ 57 0
14 NAME Cen A Group GrG 13 20 33.9 -44 58 51           ~ 253 0
15 LEDA 46680 G 13 22 02.1 -42 32 10   16.6       ~ 53 0
16 LEDA 2815822 G 13 22 12.7 -42 43 41   18.5       ~ 35 0
17 NAME Centaurus A Sy2 13 25 27.61521044 -43 01 08.8050291   8.18 6.84 6.66   ~ 4324 3
18 M 83 SBG 13 37 00.91920 -29 51 56.7400 8.85 8.11 7.52 7.21   ~ 2456 2
19 LEDA 2815823 G 13 41 38.1 -42 34 55   18.1       ~ 26 0
20 NAME Cen N G 13 48 09.2 -47 33 54           ~ 22 0
21 NAME UMi Galaxy G 15 09 11.34 +67 12 51.7   13.60 10.6     ~ 1291 0
22 NAME Dra dSph G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1273 1
23 NAME Local Group GrG ~ ~           ~ 7907 0

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2023.02.07-15:38:52

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