We present and analyze a rich data set including Subaru/SuprimeCam, HST/Advanced Camera for Surveys and Wide Field Camera 3, Keck/DEIMOS, Chandra/ACIS-I, and JVLA/C and D array for the merging cluster of galaxies ZwCl 0008.8+5215. With a joint Subaru+HST weak gravitational lensing analysis, we identify two dominant subclusters and estimate the masses to be M200 = 5.7+2.8 -1.8 × 1014 M⊙ and 1.2 +1.4 -0.6 × 1014 M⊙. We estimate the projected separation between the two subclusters to be 924+243-206kpc. We perform a clustering analysis of spectroscopically confirmed cluster member galaxies and estimate the line-of-sight velocity difference between the two subclusters to be 92 ± 164 kms-1. We further motivate, discuss, and analyze the merger scenario through an analysis of the 42 ks of Chandra/ACIS-I and JVLA/C and D array polarization data. The X-ray surface brightness profile reveals a merging gas-core reminiscent of the Bullet Cluster. The global X-ray luminosity in the 0.5-7.0 keV band is and the global X-ray temperature is 4.90 ±0.13 keV. The radio relics are polarized up to 40%, and along with the masses, velocities, and positions of the two subclusters, we input these quantities into a Monte Carlo dynamical analysis and estimate the merger velocity at pericenter to be 1800+400-300 kms-1 . This is a lower-mass version of the Bullet Cluster and therefore may prove useful in testing alternative models of dark matter (DM). We do not find significant offsets between DM and galaxies, but the uncertainties are large with the current lensing data. Furthermore, in the east, the BCG is offset from other luminous cluster galaxies, which poses a puzzle for defining DM-galaxy offsets.
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under grant No. 1518246. This material is based upon work supported by STSci grant HST-GO-13343.001-A. Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number GO5-14130X issued by the Chandra X-ray Observatory Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science