Occurrence of LINER galaxies within the galaxy group environment

GEORGINA V. COLDWELL; LUIS PEREIRA; SOL ALONSO; EMILIO DONOSO ; FERNANDA DUPLANCIC

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017 vol. 467 p. 3338 - 3346

0035-8711

We study the properties of a sample of 3967 low-ionization nuclearemission-line region (LINER) galaxies selected from SDSS-DR7, withrespect to their proximity to galaxy groups. The host galaxies of LINERshave been analysed and compared with a well-defined control sample of3841 non-LINER galaxies matched in redshift, luminosity, colour,morphology, age and stellar mass content. We find no difference betweenLINER and control galaxies in terms of the colour and age of stellarpopulation as a function of the virial mass and distance to thegeometric centre of the group. However, we find that LINERs are morelikely to populate low-density environments in spite of theirmorphology, which is typical of high-density regions such as rich galaxyclusters. For rich (poor) galaxy groups, the occurrence of LINERs isapproximately two times lower (higher) than the occurrence of matched,non-LINER galaxies. Moreover, LINER hosts do not seem to follow theexpected morphology-density relation in groups of high virial mass. Thehigh frequency of LINERs in low-density regions could be due to thecombination of a sufficient gas reservoir to power the low-ionizationemission and/or enhanced galaxy interaction rates benefiting the gasflow towards their central regions.