Mon. Not. R. Astron. Soc., 463, 1284-1290 (2016/December-1)
Faint dwarf galaxies in Hickson Compact Group 90.
ORDENES-BRICENO Y., TAYLOR M.A., PUZIA T.H., MUNOZ R.P., EIGENTHALER P., GEORGIEV I.Y., GOUDFROOIJ P., HILKER M., LANCON A., MAMON G., MIESKE S., MILLER B.W., PENG E.W. and SANCHEZ-JANSSEN R.
Abstract (from CDS):
We report the discovery of a very diverse set of five low-surface brightness (LSB) dwarf galaxy candidates in Hickson Compact Group 90 (HCG 90) detected in deep U- and I-band images obtained with Very Large Telescope/Visible Multi-Object Spectrograph. These are the first LSB dwarf galaxy candidates found in a compact group of galaxies. We measure spheroid half-light radii in the range 0.7 ≲ reff/kpc ≲ 1.5 with luminosities of -11.65 ≤ MU ≤ -9.42 and -12.79 ≤ MI ≤ -10.58 mag, corresponding to a colour range of (U - I)0 ~= 1.1-2.2 mag and surface brightness levels of µU ~= 28.1 mag arc/sec2 and µI ~= 27.4 mag/arcsec2. Their colours and luminosities are consistent with a diverse set of stellar population properties. Assuming solar and 0.02 Z☉ metallicities we obtain stellar masses in the range M*|Z☉_ ~= 10^5.7 - 6.3^ M☉ and M_*|0.02 Z☉_ ∼ 106.3–8M☉. Three dwarfs are older than 1 Gyr, while the other two significantly bluer dwarfs are younger than ∼ 2 Gyr at any mass/metallicity combination. Altogether, the new LSB dwarf galaxy candidates share properties with dwarf galaxies found throughout the Local Volume and in nearby galaxy clusters such as Fornax. We find a pair of candidates with ∼ 2 kpc projected separation, which may represent one of the closest dwarf galaxy pairs found. We also find a nucleated dwarf candidate, with a nucleus size of reff ~= 46-63 pc and magnitude M_U, 0_ = -7.42 mag and (U - I)0 = 1.51 mag, which is consistent with a nuclear stellar disc with a stellar mass in the range 10^4.9 - 6.5^ M☉.
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
galaxies: dwarf - galaxies: elliptical and lenticular, cD - galaxies: groups: individual: HCG 90 - galaxies: nuclei - galaxies: spiral - galaxies: spiral
Table 1: [OTP2016] HCG 90-DWN (Nos DW1-DW5).
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