http://arxiv.org/abs/1603.03494
Taking advantage of the Sloan Digital Sky Survey Stripe82, we have explored the spatial distribution of ultra diffuse galaxies (UDGs) within an area of 8×8 Mpc^2 centered around the galaxy cluster Abell 168 (z=0.045). This intermediate massive cluster (sigma=550 km/s) is surrounded by a complex large scale structure, rich in filaments and groups. This allows us to probe the large scale distribution of UDGs and address the question whether the infalling structures fed the cluster with new UDGs. We find that UDGs are located within the large scale structures that comprise the Abell 168 overdensity. Approximately 42% of the UDGs analysed inhabit the cluster region: ~7+-3% in the core and ~35+-7% in the outskirts whereas the remaining UDGs are found outside the main overdensity: ~19+-5% in groups and ~40% in filaments. UDGs structural properties gradually change from the lowest to the densest regions with a decrease of their stellar mass by a factor of ~1.5, an increase of their Sersic index n by a factor of ~1.25 and a decrease in their axis ratio (b/a) by a factor of ~1.13. This transformation supports the idea that UDGs probably form outside clusters and are later on accreted towards the cluster’s central regions, where they are finally destroyed by disruption. Finally, the spatial distribution of the UDGs is very similar to the one found for dwarf galaxies but significantly different from the distribution of galaxies like the Milky Way, suggesting that UDGs could be bona fide dwarfs and not failed L* galaxies.
J. Roman and I. Trujillo
Mon, 14 Mar 16
2/47
Comments: 14 pages, 12 figures, submitted, comments are welcome
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