HST/WFC3 Observations of an Off-Nuclear Superbubble in Arp 220
Abstract
We present a high spatial resolution optical and infrared study of the circumnuclear region in Arp 220, a late-stage galaxy merger. Narrowband imaging using HST/WFC3 has resolved the previously observed peak in H+[NII] emission into a bubble-shaped feature. This feature measures 1.6" in diameter, or 600 pc, and is only 1" northwest of the western nucleus. The bubble is aligned with the western nucleus and the large-scale outflow axis seen in X-rays. We explore several possibilities for the bubble origin, including a jet or outflow from a hidden active galactic nucleus (AGN), outflows from high levels of star formation within the few hundred pc nuclear gas disk, or an ultraluminous X-ray source. An obscured AGN or high levels of star formation within the inner 100 pc of the nuclei are favored based on the alignment of the bubble and energetics arguments.
Keywords
Cite
@article{arxiv.1506.03073,
title = {HST/WFC3 Observations of an Off-Nuclear Superbubble in Arp 220},
author = {Kelly E. Lockhart and Lisa J. Kewley and Jessica R. Lu and Mark G. Allen and David Rupke and Daniela Calzetti and Richard I. Davies and Michael A. Dopita and Hauke Engel and Timothy M. Heckman and Claus Leitherer and David B. Sanders},
journal= {arXiv preprint arXiv:1506.03073},
year = {2015}
}
Comments
Accepted for publication in ApJ. 12 pages, 10 figures