An extended cold gas absorber in a central cluster galaxy

Smith, Russell J.; Edge, Alastair C.

Abstract

We present the serendipitous discovery of an extended cold gas structure projected close to the brightest cluster galaxy (BCG) of the z = 0.045 cluster Abell 3716, from archival integral field spectroscopy. The gas is revealed through narrow Na D line absorption, seen against the stellar light of the BCG, which can be traced for ∼25 kpc, with a width of 2–4 kpc. The gas is offset to higher velocity than the BCG (by ∼100 km s−1), showing that it is infalling rather than outflowing; the intrinsic linewidth is ∼80 km s−1 (FWHM). Very weak H α line emission is detected from the structure, and a weak dust absorption feature is suggested from optical imaging, but no stellar counterpart has been identified. We discuss some possible interpretations for the absorber: as a projected low-surface-brightness galaxy, as a stream of gas that was stripped from an infalling cluster galaxy or as a ‘retired’ cool-core nebula filament.

Citation

Smith, R. J., & Edge, A. C. (2017). An extended cold gas absorber in a central cluster galaxy. Monthly Notices of the Royal Astronomical Society: Letters, 471(1), L66-L70. https://doi.org/10.1093/mnrasl/slx107

• Journal Article Type: Article
• Acceptance Date: Jun 23, 2017
• Online Publication Date: Jul 6, 2017
• Publication Date: Oct 11, 2017
• Deposit Date: Jul 27, 2017
• Publicly Available Date: Aug 2, 2017
• Journal: Monthly Notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 471
• Issue: 1
• Pages: L66-L70
• DOI: https://doi.org/10.1093/mnrasl/slx107
• Public URL: https://durham-repository.worktribe.com/output/1353466
• Related Public URLs: https://arxiv.org/abs/1706.08533