RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy

Details RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy

2008-06-02

arxiv.org/abs/0806.0376v1

Astrophys.J.685:138-146,2008

Astronomy and Astrophysics

Astrophysics

23 pages, 6 figures, accepted for publication in ApJ

Scientific paper

10.1086/590550

Using deep Chandra and optical spectroscopic observations, we investigate an intriguing, young massive group, RXJ1648.7+6109, at z=0.376, and we combine these observations with previous measurements to fit the scaling relations of intermediate-redshift groups and poor clusters. RXJ1648 appears to be in an early stage of formation; while it follows X-ray scaling relations, its X-ray emission is highly elongated and it lacks a central, dominant BCG. Instead, RXJ1648 contains a central string of seven bright galaxies, which have a smaller velocity dispersion, are on average brighter, and have less star formation (lower EW([OII]) and EW(H_delta)) than other group galaxies. The 4-5 brightest galaxies in this string should sink to the center and merge through dynamical friction by z=0, forming a BCG consistent with a system of RXJ1648's mass even if 5-50% of the light is lost to an intracluster light component (ICL). The L_X-T_X relation for intermediate-redshift groups/poor clusters is very similar to the low-redshift cluster relation and consistent with the low-redshift group relation. In contrast, the L_X-sigma_v and sigma_v-T_X relations reveal that intermediate-redshift groups/poor clusters have significantly lower velocity dispersions for their X-ray properties compared to low-redshift systems, however the intermediate-redshift relations are currently limited to a small range in luminosity.

Affiliated with

Also associated with

No associations

Rating

RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and RXJ1648.7+6109: Witnessing the Formation of a Massive Group/Poor Cluster and its Brightest Galaxy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-194510