Jesper Rasmussen, Xue-Ning Bai, John S. Mulchaey, J. H. van Gorkom, Tesla E. Jeltema, Ann I. Zabludoff, Eric Wilcots, Paul Martini, Duane Lee, Timothy P. Roberts
The role of environmentally induced gas stripping in driving galaxy evolution
in groups remains poorly understood. Here we present extensive Chandra and Very
Large Array mosaic observations of the hot and cold interstellar medium within
the members of the nearby, X-ray bright NGC 2563 group, a prime target for
studies of the role of gas stripping and interactions in relatively small host
halos. Our observations cover nearly all group members within a projected
radius of 1.15 Mpc (~1.4 R_vir) of the group center, down to a limiting X-ray
luminosity and HI mass of 3e39 erg/s and 2e8 M_sun, respectively. The X-ray
data are consistent with efficient ram pressure stripping of the hot gas halos
of early-type galaxies near the group core, but no X-ray tails are seen and the
limited statistics preclude strong conclusions. The HI results suggest moderate
HI mass loss from the group members when compared to similar field galaxies.
Six of the 20 HI-detected group members show HI evidence of ongoing
interactions with other galaxies or with the intragroup medium. Suggestive
evidence is further seen for galaxies with close neighbors in position-velocity
space to show relatively low HI content, consistent with tidal removal of HI.
The results thus indicate removal of both hot and cold gas from the group
members via a combination of ram pressure stripping and tidal interactions. We
also find that 16 of the 20 HI detections occur on one side of the group,
reflecting an unusual morphological segregation whose origin remains unclear.
View original:
http://arxiv.org/abs/1201.1291
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