Colours of isolated galaxies selected from the Two-Micron All-Sky Survey
arXiv:1311.4391 · doi:10.1093/mnras/stt2225
Abstract
The properties of isolated galaxies are mainly driven by intrinsic evolution and not by the external influence of their environments. Therefore the isolated galaxy sample may be considered as a reference sample to study different environmental effects. We made detailed comparisons between the near-infrared (2MASS) and optical (SDSS) colours of the 2MASS XSC selected sample of isolated 2MIG galaxies and with other objects from the wide range of denser environments (field, groups/clusters, triplets and pairs). We found that early type galaxies show similar (J-H)rest and (g-r)rest colours practically in all types of environments. Exception is for the massive early type galaxies located in compact pairs with high velocity difference (dV~180 km/s), which are significantly redder and brighter than isolated galaxies. We assume that these pairs are located in the centres of more populated groups and clusters. In general, galaxies in groups and pairs of spiral and late morphological types have redder near-infrared colours (J-H)rest than 2MIG isolated galaxies. The (g-r)rest colours of galaxies in groups and pairs with high velocity difference are also significantly redder than corresponding colours of 2MIG galaxies. On the contrary, the members of most compact pairs (dV~50 km/s, R~30 kpc) show the same (g-r)rest colour and even tend to be bluer than 2MIG galaxies. In summary, our results show that the colours of galaxies are strongly depend on the external factors.
10 pages, 7 figures, 4 tables
References in corpus (19)
- Galaxy Zoo: the dependence of morphology and colour on environment
- The Properties of Galaxies in Voids
- The AMIGA sample of isolated galaxies. V. Quantification of the isolation
- Extended Hot Halos Around Isolated Galaxies Observed in the ROSAT All-Sky Survey
- The Dependence of Galaxy Morphology and Structure on Environment and Stellar Mass
- Photometric Properties of Void Galaxies in the Sloan Digital Sky Survey DR7 Data Release
- The AMIGA sample of isolated galaxies III. IRAS data and infrared diagnostics
- Where do "red and dead" early-type void galaxies come from?
- Catalog of Isolated Galaxies Selected from the 2MASS Survey
- Photometric characterization of a well defined sample of isolated galaxies in the context of the AMIGA project
- Galaxy properties from Voids to Clusters in the SDSS-DR4
- The AMIGA sample of isolated galaxies. XI. Optical characterisation of nuclear activity
- Catalog of Nearby Isolated Galaxies in the Volume z<0.01
- High-order 3D Voronoi tessellation for identifying Isolated galaxies, Pairs and Triplets
- The AMIGA sample of isolated galaxies. VII. Far-infrared and radio continuum study of nuclear activity
- Low-Density Structures in the Local Universe. II. Nearby Cosmic Voids
- Groups of two galaxies in SDSS: implications of colours on star formation quenching time-scales
- Low Density Structures in the Local Universe. I. Diffuse Agglomerates of Galaxies
- Interacting Galaxies in Sparsely Populated Groups