2017MNRAS.466..556M


Query : 2017MNRAS.466..556M

2017MNRAS.466..556M - Mon. Not. R. Astron. Soc., 466, 556-563 (2017/March-3)

Unusual void galaxy DDO 68: implications of the HST-resolved photometry.

MAKAROV D.I., MAKAROVA L.N., PUSTILNIK S.A. and BORISOV S.B.

Abstract (from CDS):

DDO 68 (UGC 5340) is an unusual dwarf galaxy with extremely low gas metallicity [12 + log (O/H) = 7.14] residing in the nearby Lynx-Cancer void. Despite its apparent isolation, it shows both optical and H I morphological evidence for strong tidal disturbance. Here, we study the resolved stellar populations of DDO 68 using deep images from the HST archive. We determined a distance of 12.75 ± 0.41 Mpc using the tip of the red giant branch (TRGB). The star formation history reconstruction reveals that about 60 per cent of stars formed during the initial period of star formation, about 12-14 Gyr ago. During the next 10 Gyr, DDO 68 was in the quenched state, with only slight traces of star formation. The onset of the most recent burst of star formation occurred about 300 Myr ago. We find that young populations with ages of several million to a few hundred million years are widely spread across various parts of DDO 68, indicating an intense star formation episode with a high mean rate of 0.15 M yr–1. A major fraction of the visible stars in the whole system (∼80 per cent) have low metallicities: Z = Z/50-Z/20. The properties of the northern periphery of DDO 68 can be explained by an ongoing burst of star formation induced by the minor merger of a small, gas-rich, extremely metal-poor galaxy with a more typical dwarf galaxy. The current TRGB-based distance of DDO 68 implies a total negative peculiar velocity of ≃500 km s–1.

Abstract Copyright: © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: dwarf - galaxies: evolution - galaxies: individual: DDO 68 (UGC 5340) - galaxies: interactions - galaxies: stellar content - galaxies: stellar content

Simbad objects: 18

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Number of rows : 18
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 UGC 772 LSB 01 13 40.450 +00 52 39.16   17       ~ 57 0
2 [PBT2001] SBSG 0335-052 W G 03 37 38.40 -05 02 37.5   19.14     18.85 ~ 100 1
3 SDSS J070623.43+302051.3 G 07 06 23.433 +30 20 51.37           ~ 4 0
4 NAME J0723+36 system GrG 07 23 07.40 +36 22 41.0           ~ 4 0
5 AGC 194054 LSB 09 26 10.3 +33 43 15           ~ 21 0
6 Mrk 116 PaG 09 34 02.1 +55 14 25           ~ 1026 1
7 LEDA 27591 SBG 09 40 12.843 +29 35 30.30   16 16.08     ~ 42 0
8 NAME Leoncino Dwarf Galaxy bCG 09 43 32.356 +33 26 57.65           ~ 30 0
9 UGC 5209 LSB 09 45 04.196 +32 14 16.03   19       ~ 56 0
10 UGC 5272 G 09 50 22.769 +31 29 17.80   14.48   14.10   ~ 171 0
11 [CJM2014] DDO 68 C G 09 56 41.00 +29 00 54.0           ~ 5 0
12 UGC 5340 G 09 56 46.047 +28 49 43.77 14.82 14.74 14.59 14.55   ~ 193 1
13 SDSS J100036.54+303209.7 G 10 00 36.545 +30 32 09.78           ~ 10 0
14 UGC 5427 G 10 04 40.949 +29 21 51.54   15.2       ~ 53 0
15 NAME Leo P BiC 10 21 45.123 +18 05 16.89           ~ 168 0
16 HS 1053+3624 G 10 56 40.349 +36 08 27.95   17.90       ~ 11 0
17 NAME Local Void vid 18 38 +18.0           ~ 166 0
18 NAME Local Group GrG ~ ~           ~ 7359 0

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2021.09.26-08:20:09

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