2016A&A...590A..20V


C.D.S. - SIMBAD4 rel 1.7 - 2020.01.27CET10:02:11

2016A&A...590A..20V - Astronomy and Astrophysics, volume 590A, 20-20 (2016/6-1)

The abundance and spatial distribution of ultra-diffuse galaxies in nearby galaxy clusters.

VAN DER BURG R.F.J., MUZZIN A. and HOEKSTRA H.

Abstract (from CDS):

Recent observations have highlighted a significant population of faint but large (reff>1.5kpc) galaxies in the Coma cluster. The origin of these ultra diffuse galaxies (UDGs) remains puzzling, as the interpretation of these observational results has been hindered by the (partly) subjective selection of UDGs, and the limited study of only the Coma (and some examples in the Virgo-) cluster. In this paper we extend the study of UDGs using eight clusters in the redshift range 0.044<z<0.063 with deep g- and r-band imaging data taken with MegaCam at the CFHT. We describe an automatic selection pipeline for quantitative identification, and tested for completeness using image simulations of these galaxies. We find that the abundance of the UDGs we can detect increases with cluster mass, reaching ∼200 in typical haloes of M200≃1015M. For the ensemble cluster we measure the size distribution of UDGs, their colour-magnitude distribution, and their completeness-corrected radial density distribution within the clusters. The morphologically-selected cluster UDGs have colours consistent with the cluster red sequence, and have a steep size distribution that, at a given surface brightness, declines as n[dex–1]∝reff–3.4±0.2. Their radial distribution is significantly steeper than NFW in the outskirts, and is significantly shallower in the inner parts. We find them to follow the same radial distribution as the more massive quiescent galaxies in the clusters, except within the core region of r<= 0.15xR200 (or<=300kpc). Within this region the number density of UDGs drops and is consistent with zero. These diffuse galaxies can only resist tidal forces down to this cluster-centric distance if they are highly centrally dark-matter dominated. The observation that the radial distribution of more compact dwarf galaxies (reff<1.0kpc) with similar luminosities follows the same distribution as the UDGs, but exist down to a smaller distance of 100kpc from the cluster centres, may indicate that they have similarly massive sub-haloes as the UDGs. Although a number of scenarios can give rise to the UDG population, our results point to differences in the formation history as the most plausible explanation.

Abstract Copyright: © ESO, 2016

Journal keyword(s): galaxies: dwarf - galaxies: formation - galaxies: evolution - galaxies: clusters: general

Simbad objects: 11

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Number of rows : 11

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 ACO 85 ClG 00 41 37.8 -09 20 33           ~ 774 0
2 ACO 119 ClG 00 56 16.8 -01 15 00           ~ 510 2
3 ACO 133 ClG 01 02 39.0 -21 57 15           ~ 328 1
4 ACO 553 ClG 06 12 25.8 +48 37 26           ~ 42 0
5 ACO 780 ClG 09 18 30 -12 15.7           ~ 422 0
6 NAME Vir I ClG 12 26 32.1 +12 43 24   10.00 8.49     ~ 5701 0
7 ACO 1656 ClG 12 59 48.7 +27 58 50           ~ 4132 2
8 ACO 1781 ClG 13 45 32.70 +29 31 49.6           ~ 61 0
9 ACO 1795 ClG 13 49 00.5 +26 35 07           ~ 1143 0
10 ACO 1991 ClG 14 54 30.2 +18 37 51           ~ 301 1
11 NAME NGC 5920 Group ClG 15 21 50.7 +07 42 18     15.13     ~ 281 0

    Equat.    Gal    SGal    Ecl

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2020.01.27-10:02:11

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