LINER galaxy properties and the local environment

COLDWELL, G.; ALONSO, SOL; DUPLANCIC, F.; MESA V.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2018 vol. 476 p. 2457 - 2464

0035-8711

We analyse the properties of a sample of 5560 LINER galaxies selected from SDSS-DR12, at low redshift, for a complete range of local density environments. The host LINER galaxies were studied and compared with a well-defined control sample of 5553 non-LINER galaxies matched in redshift, luminosity, morphology and local density. By studying the distributions of galaxy colours and stellar age population we find that LINERs are redder and older than the control sample in the wide range ofdensities. In addition, LINERs are older than the control sample, at a given galaxy colour, indicating that some external process could have accelerated the evolution of the stellar population.The analysis of the host properties shows that the control sample exhibits a strong relation between the colours, ages and the local density, while more than 90% of the LINERs are redder and older than the mean values, independently of the neighbourhood density. Furthermore, a detailed study in three local density ranges shows that, while control sample galaxies are redder and older as a function of its stellar mass anddensity, LINER galaxies mismatch the known morphology-density relation shown by galaxies without low-ionization features. The results give support to the contribution of hot and old stars as viable mechanisms for the low ionization emission although the presence of nuclear activity is not discarded.