2012ApJ...744..157M

Query : 2012ApJ...744..157M

2012ApJ...744..157M - Astrophys. J., 744, 157 (2012/January-2)

The ACS LCID project. VII. The blue stragglers population in the isolated dSph galaxies Cetus and Tucana.

MONELLI M., CASSISI S., MAPELLI M., BERNARD E.J., APARICIO A., SKILLMAN E.D., STETSON P.B., GALLART C., HIDALGO S.L., MAYER L. and TOLSTOY E.

Abstract (from CDS):

We present the first investigation of the Blue Straggler star (BSS) population in two isolated dwarf spheroidal galaxies of the Local Group, Cetus and Tucana. Deep Hubble Space Telescope/Advanced Camera for Surveys photometry allowed us to identify samples of 940 and 1214 candidates, respectively. The analysis of the star formation histories of the two galaxies suggests that both host a population of BSSs. Specifically, if the BSS candidates are interpreted as young main sequence stars, they do not conform to their galaxy's age-metallicity relationship. The analysis of the luminosity function and the radial distributions supports this conclusion, and suggests a non-collisional mechanism for the BSS formation, from the evolution of primordial binaries. This scenario is also supported by the results of new dynamical simulations presented here. Both galaxies coincide with the relationship between the BSS frequency and the absolute visual magnitude MV found by Momany et al. If this relationship is confirmed by larger sample, then it could be a valuable tool to discriminate between the presence of BSSs and galaxies hosting truly young populations.

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Journal keyword(s): blue stragglers - galaxies: individual (Cetus dSph, Tucana dSph) - galaxies: evolution - Galaxy: stellar content - Local Group

Simbad objects: 12

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Number of rows : 12
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 NAME Cetus Dwarf Galaxy G 00 26 10.8 -11 03 14     13.2     ~ 257 0
2 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
3 NAME Pisces I G 01 03 55.0 +21 53 06   16.18 14.3     ~ 404 0
4 IC 1613 GiC 01 04 48.4071 +02 07 10.185   10.42 10.01 9.77   ~ 1316 2
5 NAME Phoenix Dwarf Galaxy Sy1 01 51 06.3 -44 26 41   13.48 13.2 12.69   ~ 575 2
6 MCG-06-07-001 G 02 39 59.3 -34 26 57   9.02 7.4     ~ 1894 1
7 Z 153-10 G 09 59 26.46 +30 44 47.0 14.08 13.54 13.26 13.33   ~ 652 0
8 M 3 GlC 13 42 11.62 +28 22 38.2     6.39     ~ 2593 0
9 Z 318-18 G 15 09 08.0 +67 13 21   13.60 10.6     ~ 1459 0
10 Z 300-12 G 17 20 14.335 +57 55 16.39   12.40 10.6     ~ 1428 1
11 NAME Tuc Galaxy G 22 41 49.6 -64 25 10   15.7 15.2     ~ 324 0
12 NAME Local Group GrG ~ ~           ~ 9325 0

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