NGC 4261 and NGC 4697: rejuvenated elliptical galaxies
Abstract
Chandra images present evidence for a non-uniform spatial distribution of discrete X-ray sources in the elliptical galaxy NGC 4261. This non-uniform distribution is inconsistent with the optical morphology of NGC 4261 at greater than a 99.9% confidence level. Similar evidence is seen in one more elliptical galaxy (NGC 4697; 98% confidence level) out of five cases we investigated. NGC 4261 and NGC 4697 have old stellar populations (9-15 Gyrs) and fine structure parameters of 1 and 0 respectively, suggesting no recent merging activity. On the basis of simulations of galaxy interactions, we propose that the X-ray sources responsible for the non-uniform distribution are associated with young stellar populations, related to the rejuvenating fall-back of material in tidal tails onto a relaxed merger remnant, or shock induced star-formation along the tidal tails.
Cite
@article{arxiv.astro-ph/0310567,
title = {NGC 4261 and NGC 4697: rejuvenated elliptical galaxies},
author = {A. Zezas and L. Hernquist and G. Fabbiano and J. Miller},
journal= {arXiv preprint arXiv:astro-ph/0310567},
year = {2009}
}
Comments
Accepted for publication in Ap.J. Letters