Blue colours of BL Lac host galaxies
Astrophysics
2009-11-10 v1
Abstract
Near-infrared and optical imaging of BL Lac host galaxies is used to investigate their colour properties. We find that the R-H colour and colour gradient distributions of the BL Lac hosts are much wider than those for normal ellipticals, and many objects have very blue hosts and/or steep colour gradients. The blue colours are most likely caused by recent star formation. The lack of obvious signs of interaction may, however, require a significant time delay between the interaction event with associated star formation episodes and the onset of the nuclear activity.
Keywords
Cite
@article{arxiv.astro-ph/0404372,
title = {Blue colours of BL Lac host galaxies},
author = {J. K. Kotilainen and R. Falomo},
journal= {arXiv preprint arXiv:astro-ph/0404372},
year = {2009}
}
Comments
2 pages, 1 figure, to appear in the proceedings of "The Interplay among Black Holes, Stars and ISM in Galactic Nuclei", IAU 222, eds. T. Storchi Bergmann, L.C. Ho, and H.R. Schmitt