2015A&A...581A..84T


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.04CEST02:51:18

2015A&A...581A..84T - Astronomy and Astrophysics, volume 581A, 84-84 (2015/9-1)

Optical-near-IR analysis of globular clusters in the IKN dwarf spheroidal: a complex star formation history.

TUDORICA A., GEORGIEV I.Y. and CHIES-SANTOS A.L.

Abstract (from CDS):

Age, metallicity, and spatial distribution of globular clusters (GCs) provide a powerful tool for reconstructing major star-formation episodes in galaxies. IKN is a faint dwarf spheroidal (dSph) in the M 81group of galaxies. It contains five old GCs, which makes it the galaxy with the highest known specific frequency (SN=126). We estimate the photometric age, metallicity, and spatial distribution of the poorly studied IKN GCs. We search SDSS for GC candidates beyond the HST/ACS field of view, which covers half of IKN. To break the age-metallicity degeneracy in the V-I colour, we used WHT/LIRIS KS-band photometry and derived photometric ages and metallicities by comparison with SSP models in the V,I,Ks colour space. IKN GCs' VIKs colours are consistent with old ages (≥8Gyr) and a metallicity distribution with a higher mean than is typical for such a dSph ([Fe/H]≃-1.4–0.2+0.6dex). Their photometric mass range (0.5<MGC<4x105M) implies an unusually high mass ratio between GCs and field stars, of 10.6%. Mixture model analysis of the RGB field stars' metallicity suggests that 72% of the stars may have formed together with the GCs. Using the most massive GC-SFR relation, we calculated a star formation rate (SFR) of ∼10M/yr during its formation epoch. We note that the more massive GCs are closer to the galaxy photometric centre. IKN GCs also appear spatially aligned along a line close to the major axis of the IKN and nearly orthogonal to the plane of spatial distribution of galaxies in the M 81 group. We identify one new IKN GC candidate based on colour and the PSF analysis of the SDSS data. The evidence of i) broad and high metallicity distribution of the field IKN RGB stars and its GCs, ii) high fraction, and iii) spatial alignment of IKN GCs supports a scenario for tidally triggered, complex IKN's star formation history in the context of interactions with galaxies in the M 81 group.

Abstract Copyright:

Journal keyword(s): galaxies: individual: IKN - globular clusters: general

Nomenclature: Table 4: [TGC2015] N N=2 (Nos 6, 7).

Simbad objects: 23

goto Full paper

goto View the reference in ADS

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 - 2020
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 10902 1
2 NAME Fornax Dwarf Spheroidal G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1473 1
3 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 14826 1
4 NAME M 81-82 Group GrG 09 55 +69.1           ~ 634 0
5 M 81 Sy2 09 55 33.17306143 +69 03 55.0609270   7.89 6.94     ~ 3962 5
6 M 82 IG 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 5331 6
7 NGC 3077 GiP 10 03 19.0965510921 +68 44 01.556166166 11.23 10.85 10.14 9.74   ~ 691 0
8 [GPH2009] IKN-04 Gl? 10 08 04.7817700893 +68 24 53.100713145           ~ 2 0
9 [TGC2015] 6 Gl? 10 08 05.160 +68 25 29.13           ~ 1 0
10 [GPH2009] IKN-03 Gl? 10 08 05.26 +68 24 33.8           ~ 3 0
11 [GPH2009] IKN-05 Gl? 10 08 05.4998537340 +68 24 57.379798352           ~ 3 0
12 NAME IKN G 10 08 05.9 +68 23 57           ~ 61 0
13 [GPH2009] IKN-01 Gl? 10 08 07.14 +68 23 36.6           ~ 2 0
14 [TGC2015] 7 Gl? 10 08 08.850 +68 28 36.72           ~ 1 0
15 [GPH2009] IKN-02 Gl? 10 08 10.79 +68 24 05.6           ~ 2 0
16 IC 2547 G 10 10 04.4794033616 +36 30 08.705016828   15.7       ~ 12 0
17 NAME Hydra I Cluster ClG 10 36 36.0 -27 31 04           ~ 774 1
18 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6207 3
19 M 60 GiP 12 43 40.008 +11 33 09.40   10.3       ~ 1250 0
20 ACO 3526 ClG 12 48 51.8 -41 18 21           ~ 971 2
21 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4208 2
22 NGC 6822 G 19 44 56.199 -14 47 51.29   18 8.1     ~ 1428 0
23 NAME Local Group GrG ~ ~           ~ 6970 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2015A&A...581A..84T and select 'bookmark this link' or equivalent in the popup menu


2020.07.04-02:51:18

© Université de Strasbourg/CNRS

    • Contact