Document Type

Article

Publication Date

7-14-2008

Publication Title

Astronomical Journal

DOI

10.1086/591124

ISSN

1538-3881

Abstract

We report the discovery of a ~500 kpc H I extension southwest of the Virgo Cluster H I-rich pair NGC 4532/DDO 137, detected as part of the Arecibo Legacy Fast ALFA (ALFALFA) Survey. The feature is the longest and most massive H I tail structure so far found in the Virgo Cluster and, at 1.8 Mpc from M87, the most distant from the main concentration of the intracluster medium. The structure is spatially and spectrally separated into two ridges and is defined by diffuse emission and discrete clumps of mass (2.5–6.8) × 107 M☉. All emission is blueshifted with respect to the NGC 4532/DDO 137 pair emission. Including diffuse emission, the structure has a total mass of up to 7 × 108 M☉, equivalent to ~10% of the system's H I mass. Optical R-band imaging finds no counterparts to a level of 26.5 mag arcsec−2. The characteristics of the structure appear most consistent with a tidal origin.

Comments

This version of the paper was obtained from arXIV.org. In order for the work to be deposited in arXIV.org, the author must have copyright or it must be available under the Creative Commons Attribution license, Creative Commons Attribution-Noncommercial-ShareAlike license, or Create Commons Public Domain Declaration. The publisher's final edited version of this article will be available at The Astrophysical Journal.

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