Multi-wavelength Analysis of the Merging Galaxy Cluster A115. (arXiv:1812.08797v1 [astro-ph.CO])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kim_M/0/1/0/all/0/1">Mincheol Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Jee_M/0/1/0/all/0/1">M. James Jee</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Finner_K/0/1/0/all/0/1">Kyle Finner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Golovich_N/0/1/0/all/0/1">Nathan Golovich</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Wittman_D/0/1/0/all/0/1">David M. Wittman</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Weeren_R/0/1/0/all/0/1">R. J. van Weeren</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dawson_W/0/1/0/all/0/1">W. A. Dawson</a>
A115 is a merging galaxy cluster at $zsim0.2$ with a number of remarkable
features including a giant ($sim2.5$ Mpc) radio relic, two asymmetric X-ray
peaks with trailing tails, and a peculiar line-of-sight velocity structure. We
present a multi-wavelength study of A115 using optical imaging data from
Subaru, X-ray data from $Chandra$, and spectroscopic data from the Keck/DEIMOS
and MMT/Hectospec instruments. Our weak-lensing analysis shows that the cluster
is comprised of two subclusters whose mass centroids are in excellent agreement
with the two BCG positions ($lesssim10$”). By modeling A115 with a
superposition of two Navarro-Frenk-White halos, we determine the masses of the
northern and southern subclusters to be $M_{200}=1.58_{-0.49}^{+0.56}times
10^{14} text{M}_{odot}$ and $3.15_{-0.71}^{+0.79}times 10^{14}
text{M}_{odot}$, respectively. Combining the two halos, we estimate the total
cluster mass to be $M_{200}=6.41_{-1.04}^{+1.08}times10^{14} text{M}_{odot}$
at $R_{200}=1.67_{-0.09}^{+0.10}$ Mpc. These weak-lensing masses are
significantly (a factor of 3-10) lower than what is implied by the X-ray and
optical spectroscopic data. We attribute the difference to the gravitational
and hydrodynamic disruption caused by the collision between the two
subclusters.
A115 is a merging galaxy cluster at $zsim0.2$ with a number of remarkable
features including a giant ($sim2.5$ Mpc) radio relic, two asymmetric X-ray
peaks with trailing tails, and a peculiar line-of-sight velocity structure. We
present a multi-wavelength study of A115 using optical imaging data from
Subaru, X-ray data from $Chandra$, and spectroscopic data from the Keck/DEIMOS
and MMT/Hectospec instruments. Our weak-lensing analysis shows that the cluster
is comprised of two subclusters whose mass centroids are in excellent agreement
with the two BCG positions ($lesssim10$”). By modeling A115 with a
superposition of two Navarro-Frenk-White halos, we determine the masses of the
northern and southern subclusters to be $M_{200}=1.58_{-0.49}^{+0.56}times
10^{14} text{M}_{odot}$ and $3.15_{-0.71}^{+0.79}times 10^{14}
text{M}_{odot}$, respectively. Combining the two halos, we estimate the total
cluster mass to be $M_{200}=6.41_{-1.04}^{+1.08}times10^{14} text{M}_{odot}$
at $R_{200}=1.67_{-0.09}^{+0.10}$ Mpc. These weak-lensing masses are
significantly (a factor of 3-10) lower than what is implied by the X-ray and
optical spectroscopic data. We attribute the difference to the gravitational
and hydrodynamic disruption caused by the collision between the two
subclusters.
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