On the properties of compact groups identified in different photometric bands

Abstract

Historically, compact group catalogues vary not only in their identification algorithms and selection functions, but also in their photometric bands. Differences between compact group catalogues have been reported. However, it is difficult to assess the impact of the photometric band in these differences given the variety of identification algorithms. We used the mock lightcone built by Henriques et al. (2012) to identify and compare compact groups in three different photometric bands: $K$, $r$, and $u$. We applied the same selection functions in the three bands, and found that compact groups in the u-band look the smallest in projection, the difference between the two brightest galaxies is the largest in the K-band, while compact groups in the r-band present the lowest compactness. We also investigated the differences between samples when galaxies are selected only in one particular band (pure compact groups) and those that exist regardless the band in which galaxies were observed (common compact groups). We found that the differences between the total samples are magnified, but also some others arise: pure-r compact groups are the largest in projection; pure-u compact groups have the brightest first ranked galaxies, and the most similar two first ranked galaxies; pure-K compact groups have the highest compactness and the most different two first ranked galaxies; and common compact groups show the largest percentage of physically dense groups. Therefore, without a careful selection and identification of the samples, the characteristic features of group properties in a particular photometric band could be overshadowed.

arXiv comment9 pages, 3 figures, 5 tables. Accepted for publication in MNRAS

References in corpus (15)

• The Sloan Digital Sky Survey: Technical Summary
• Simulating the joint evolution of quasars, galaxies and their large-scale distribution
• From dwarf spheroidals to cDs: Simulating the galaxy population in a LCDM cosmology
• Spectral Irradiance Calibration in the Infrared. XIV: the Absolute Calibration of 2MASS
• Galaxy And Mass Assembly (GAMA): mass-size relations of z$<$0.1 galaxies subdivided by Sérsic index, colour and morphology
• The recycling of gas and metals in galaxy formation: predictions of a dynamical feedback model
• Confronting theoretical models with the observed evolution of the galaxy population out to z=4
• Compact groups in theory and practice - III. Compact groups of galaxies in the Sixth Data Release of the Sloan Digital Sky Survey
• Compact groups in the UZC galaxy sample
• The Galaxy Evolution Explorer (GALEX). Its legacy of UV surveys, and science highlights
• The host galaxies and black-hole:galaxy mass ratios of luminous quasars at z~4
• Compact Groups of Galaxies selected by stellar mass: The 2MASS Compact Group Catalogue
• Compact groups from the Millennium Simulations: I. Their Nature and the completeness of the Hickson sample
• Compact Groups of Galaxies in the Las Campanas Redshift Survey
• Star-Forming Compact Groups (SFCGs): An ultraviolet search for a local sample

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• Compact groups from semi-analytical models of galaxy formation -- I: a comparative study of frequency and nature
• Compact groups from semi-analytical models of galaxy formation -- III: purity and completeness of Hickson-like catalogues
• Compact groups from semi-analytical models of galaxy formation -- II: Different assembly channels
• Hickson-like compact groups inhabiting different environments
• The Occurrence of Compact Groups of Galaxies Through Cosmic Time
• Structure and large scale environment of galaxy pairs in the S-PLUS DR4
• Compact groups of galaxies in GAMA -- Probing the densest minor systems at intermediate redshifts
• Compact groups from semi-analytical models of galaxy formation -- VI: Evolution of the two first-ranked galaxies