2021MNRAS.508.1064M

Query : 2021MNRAS.508.1064M

2021MNRAS.508.1064M - Mon. Not. R. Astron. Soc., 508, 1064-1083 (2021/November-3)

Variable stars in Local Group galaxies - V. The fast and early evolution of the low-mass Eridanus II dSph galaxy.

MARTINEZ-VAZQUEZ C.E., MONELLI M., CASSISI S., TAIBI S., GALLART C., VIVAS A.K., WALKER A.R., MARTIN-RAVELO P., ZENTENO A., BATTAGLIA G., BONO G., CALAMIDA A., CAROLLO D., CICUENDEZ L., FIORENTINO G., MARCONI M., SALVADORI S., BALBINOT E., BERNARD E.J., DALL'ORA M. and STETSON P.B.

Abstract (from CDS):

We present a detailed study of the variable star population of Eridanus II (Eri II), an ultra-faint dwarf galaxy that lies close to the Milky Way virial radius. We analyse multi-epoch g, r, i ground-based data from Goodman and the Dark Energy Camera, plus F475W, F606W, F814W space data from the Advanced Camera for Surveys. We report the detection of 67 RR Lyrae (RRL) stars and 2 Anomalous Cepheids, most of them new discoveries. With the RRL stars, we measure the distance modulus of Eri II, µ0 = 22.84 ± 0.05 mag (D☉ = 370 ± 9 kpc), and derive a metallicity spread of 0.3 dex (0.2 dex intrinsic). The colour distribution of the horizontal branch (HB) and the period distribution of the RRL stars can be nicely reproduced by a combination of two stellar models of [Fe/H] = (-2.62, -2.14). The overall low metallicity is consistent with the red giant branch bump location, 0.65 mag brighter than the HB. These results are in agreement with previous spectroscopic studies. The more metal-rich RRL and the RRab stars have greater central concentration than the more metal-poor RRL and the RRc stars that are mainly located outside ∼1 rh. This is similar to what is found in larger dwarf galaxies such as Sculptor, and in agreement with an outside-in galaxy formation scenario. This is remarkable in such a faint dwarf galaxy with an apparently single and extremely short (<1 Gyr) star formation burst. Finally, we have derived new and independent structural parameters for Eri II and its star cluster using our new data that are in very good agreement with previous estimates.

Abstract Copyright: © 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society

Journal keyword(s): stars: variables: RR Lyrae - galaxies: evolution - galaxies: individual: Eri II - Local Group - galaxies: stellar content

Status at CDS : Examining the need for a new acronym. // All or part of tables of objects will be ingested in SIMBAD with priority 1.

Simbad objects: 29

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Number of rows : 29
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 ESO 410-5 LSB 00 15 31.21 -32 10 49.9   15.32 14.9 14.58   ~ 120 1
2 NAME Andromeda XXV G 00 30 08.9 +46 51 07     14.8     ~ 120 0
3 NGC 147 GiG 00 33 12.120 +48 30 31.46   12.0 9.5     ~ 720 1
4 NGC 185 Sy2 00 38 57.9400026024 +48 20 15.035874648   9.10 9.2     ~ 840 1
5 M 31 AGN 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 13622 1
6 NAME Andromeda XI G 00 46 20.0 +33 48 05     17.5     ~ 130 0
7 NAME Andromeda XIII G 00 51 51.0 +33 00 16     18.1     ~ 128 0
8 NAME Pisces V G 00 59 29.8 +32 22 36     14.4     ~ 149 0
9 NAME Scl Group GrG 01 00 06 -33 44.2           ~ 526 0
10 NAME Sculptor Dwarf Galaxy G 01 00 09.4 -33 42 32   9.79 8.6 8.81   ~ 1498 4
11 IC 1613 GiC 01 04 48.4071 +02 07 10.185   10.42 10.01 9.77   ~ 1316 2
12 NAME Andromeda XV G 01 14 18.7 +38 07 03     14.6     ~ 123 0
13 NAME Andromeda XXIII G 01 29 21.8 +38 43 08     14.2     ~ 88 0
14 NAME Eridanus II G 03 44 21.1 -43 32 00           ~ 216 0
15 NAME Eridanus II Cluster Cl* 03 44 22.20 -43 31 59.2           ~ 10 0
16 NAME Ret GlC 04 36 10.15 -58 51 34.8   14.00 14.25 13.50   ~ 177 1
17 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 19090 0
18 NAME Car III Dwarf Galaxy G 07 38 31.2 -57 53 59           ~ 81 0
19 NAME Leo T G 09 34 53.4 +17 03 05     15.1     ~ 434 0
20 NAME Antlia II Dwarf Galaxy G 09 35 32.8 -36 46 02           ~ 109 0
21 Z 153-10 G 09 59 26.46 +30 44 47.0 14.08 13.54 13.26 13.33   ~ 652 0
22 Z 64-73 G 10 08 28.12 +12 18 23.4   11.3 10.0     ~ 1284 1
23 NAME Willman 1 G 10 49 21.0 +51 03 00     15.2     ~ 345 0
24 Z 126-111 G 11 13 28.13 +22 09 10.1   12.9 12.0     ~ 899 0
25 NAME Crater II Dwarf Galaxy G 11 49 14 -18 24.8           ~ 176 0
26 M 22 GlC 18 36 23.94 -23 54 17.1           ~ 1459 0
27 NAME Lacerta I G 22 58 16.3 +41 17 28           ~ 53 0
28 NAME Andromeda VII GiG 23 26 31.0 +50 40 33   13.6 11.8     ~ 222 1
29 NAME Local Group GrG ~ ~           ~ 9325 0

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