2010A&A...521A..43L


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.21CEST08:22:12

2010A&A...521A..43L - Astronomy and Astrophysics, volume 521, A43-43 (2010/10-1)

Dwarf spheroidals in the M 81 group - metallicity distribution functions and population gradients.

LIANOU S., GREBEL E.K. and KOCH A.

Abstract (from CDS):

We study the dwarf spheroidal galaxies in the nearby M81 group in order to construct their photometric metallicity distributions and to investigate the potential presence of population gradients. We select all the dwarf spheroidals with available Hubble Space Telescope/Advanced Camera for Surveys archival observations, nine in total. We interpolate isochrones so as to assign a photometric metallicity to each star within a selection box in the color-magnitude diagram of each dwarf galaxy. We assume that the dwarf spheroidals contain mainly an old stellar population. In order to search for metallicity gradients, we examine the spatial distribution of two stellar populations that we separate according to their metallicities. As a result, we present the photometric metallicity distribution functions, the cumulative histograms and smoothed density maps of the metal-poor and metal-rich stars as well as of the intermediate-age stars. From our photometric data we find that all the dwarf spheroidals show a wide range in metallicities, with mean values that are typical for old and metal-poor systems, with the exception of one dwarf spheroidal, namely IKN. Some of our dwarf spheroidals exhibit characteristics of transition-type dwarfs. Compared to the Local Group transition type dwarfs, the M81 group ones appear to have mean metallicity values slightly more metal-rich at a given luminosity. All the dwarf spheroidals considered here appear to exhibit either population gradients or spatial variations in the centroids of their metal-poor and metal-rich population. In addition, there are luminous AGB stars detected in all of them with spatial distributions suggesting that they are well mixed with the old stars.

Abstract Copyright:

Journal keyword(s): galaxies: dwarf - galaxies: stellar content - galaxies: structure - galaxies: interactions - galaxies: groups: individual: M81 group

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 - 2019
#notes
1 NGC 185 Sy2 00 38 57.970 +48 20 14.56   9.10 9.2     ~ 711 1
2 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1406 1
3 UGCA 133 G 07 34 11.5 +66 52 47 16.40 15.48 14.80 14.76   ~ 63 0
4 NGC 2403 AGN 07 36 51.396 +65 36 09.17 9.31 8.84 8.38 8.19   ~ 1570 1
5 NAME F8D1 G 09 44 47.1 +67 26 19   14.60 13.85     ~ 55 0
6 NAME F6D1 GiG 09 45 10.0 +68 45 54   17.5       ~ 38 0
7 NAME F12D1 G 09 50 10.0 +67 30 24   15.6       ~ 43 1
8 NAME M 81-82 Group GrG 09 55 +69.1           ~ 615 0
9 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3888 5
10 LEDA 28731 G 09 57 03.0 +68 35 31   15.17       ~ 93 1
11 UGC 5336 G 09 57 32.1 +69 02 46 15.19 15.15 14.10 14.12   ~ 280 4
12 LEDA 2807133 GiG 10 00 16.0 +63 11 05           ~ 36 1
13 LEDA 29231 G 10 04 40.3 +68 15 20   17.43 16.72     ~ 62 0
14 UGC 5428 G 10 05 06.2 +66 33 31 17.89 16.82 16.09 15.73   ~ 88 1
15 UGC 5442 G 10 07 01.70 +67 49 38.4 17.09 15.73 15.07 14.81   ~ 71 1
16 NAME IKN G 10 08 05.9 +68 23 57           ~ 58 0
17 LEDA 4689216 GiG 10 21 25.2 +71 06 58           ~ 43 0
18 LEDA 30664 G 10 26 28.0 +67 39 35   15.8       ~ 66 1
19 LEDA 31286 G 10 34 31.9 +66 00 42   16.7       ~ 44 1
20 NAME Centaurus A Sy2 13 25 27.61509104 -43 01 08.8056025   8.18 6.84 6.66   ~ 3886 3
21 NAME Andromeda VII GiG 23 26 31.7 +50 40 33   13.6 11.8     ~ 167 1
22 NAME Peg dSph GiG 23 51 46.4 +24 35 11   14.5 13.2     ~ 207 2
23 NAME Local Group GrG ~ ~           ~ 6660 0

    Equat.    Gal    SGal    Ecl

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2019.10.21-08:22:12

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