The tree clustering technique and the physical reality of galaxy groups

Sabry, M.; Issa, Islam; Abdel-Rahman, H. I.; Shaker, A. A.

doi:10.1016/j.nrjag.2012.12.002

Cited by 2 publications

(4 citation statements)

References 19 publications

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“…We define the outlier galaxy as the galaxy that has different color than the other galaxy members in a given group according to (Sabry et al 2012) criterion. Our method is applied to detect these outlier galaxies in the studied sample of groups.…”

Section: Methods and Criteriamentioning

confidence: 99%

“…The distance measure used is the "Euclidean distance coefficient" (EDC), denoted here by (𝑒 𝑖𝑗 ) as expressed in Eq. ( 1) following (Mohamed & Fouad 2017;Sabry et al 2012).…”

Section: Methods and Criteriamentioning

confidence: 99%

“…This study aims to identify interloper galaxies of small groups of five members (quintets) based on their color dissimilarities to the other members of the galaxy group by using a distance measure technique following (Mohamed & Fouad 2017;Sabry et al 2012) with a specific selection criteria.…”

Section: Introductionmentioning

confidence: 99%

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Colour similarity study among small galaxy groups members

Fouad

Awad

Shaker

et al. 2019

NRIAG Journal of Astronomy and Geophysics

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A B S T R A C TWe applied a membership test based on the color similarity of group members to detect the discordant galaxies in small groups (quintets) that had been determined by the Friends-of-Friends (FoF) algorithm. Our method depends on the similarity of the color indices (u-g) and (g-r) of the group members. The chosen sample of quintets was extracted from "Fluxand volume-limited groups for SDSS galaxies" catalog which is a spectroscopic sample of galaxies originally taken from the Sloan Digital Sky Survey -Data Release 10 (SDSS-DR10). The sample included 282 quintets with a total number of 1410 galaxies. The similarity measure used in this study is the Euclidean distance. The calculations showed that 73.4% of the group samples (207 out of 282 quintet groups) have galaxies with similar colors (u-g) and (g-r). Each of the remainder groups (75 systems) has an interloper galaxy with different colors than the other members, and hence they became quadrants. We found that group members tend to be more luminous than outliers. We conclude that using the similarities in the color indices between group members gives better identification of group membership.

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Section: Methods and Criteriamentioning

confidence: 99%

“…The distance measure used is the "Euclidean distance coefficient" (EDC), denoted here by (𝑒 𝑖𝑗 ) as expressed in Eq. ( 1) following (Mohamed & Fouad 2017;Sabry et al 2012).…”

Section: Methods and Criteriamentioning

confidence: 99%