Assembling a RELIC at Redshift 1: Spectroscopic Observations of Galaxies in the RELICS Cluster SPT-CLJ0615-5746. (arXiv:1905.00914v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Connor_T/0/1/0/all/0/1">Thomas Connor</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kelson_D/0/1/0/all/0/1">Daniel D. Kelson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Blanc_G/0/1/0/all/0/1">Guillermo A. Blanc</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boutsia_K/0/1/0/all/0/1">Konstantina Boutsia</a>
We present a catalog of spectroscopic redshifts for SPT-CLJ0615$-$5746, the
most distant cluster in the Reionization Lensing Cluster Survey (RELICS). Using
Nod & Shuffle multi-slit observations with LDSS-3 on Magellan, we identify
${sim}50$ cluster members and derive a cluster redshift of $z_c = 0.972$, with
a velocity dispersion of $sigma = 1235 pm 170 textrm{km} textrm{s}^{-1}$.
We calculate a cluster mass using a $sigma_{200}-M_{200}$ scaling relation of
$M_{200} = (9.4 pm 3.6) times 10^{14} M_odot$, in agreement with previous,
independent mass measurements of this cluster. In addition, we examine the
kinematic state of SPT-CLJ0615$-$5746, taking into consideration prior
investigations of this system. With an elongated profile in lensing mass and
X-ray emission, a non-Gaussian velocity dispersion that increases with
clustercentric radius, and a brightest cluster galaxy not at rest with the bulk
of the system, there are multiple cluster properties that, while not
individually compelling, combine to paint a picture that SPT-CLJ0615$-$5746 is
currently being assembled.
We present a catalog of spectroscopic redshifts for SPT-CLJ0615$-$5746, the
most distant cluster in the Reionization Lensing Cluster Survey (RELICS). Using
Nod & Shuffle multi-slit observations with LDSS-3 on Magellan, we identify
${sim}50$ cluster members and derive a cluster redshift of $z_c = 0.972$, with
a velocity dispersion of $sigma = 1235 pm 170 textrm{km} textrm{s}^{-1}$.
We calculate a cluster mass using a $sigma_{200}-M_{200}$ scaling relation of
$M_{200} = (9.4 pm 3.6) times 10^{14} M_odot$, in agreement with previous,
independent mass measurements of this cluster. In addition, we examine the
kinematic state of SPT-CLJ0615$-$5746, taking into consideration prior
investigations of this system. With an elongated profile in lensing mass and
X-ray emission, a non-Gaussian velocity dispersion that increases with
clustercentric radius, and a brightest cluster galaxy not at rest with the bulk
of the system, there are multiple cluster properties that, while not
individually compelling, combine to paint a picture that SPT-CLJ0615$-$5746 is
currently being assembled.
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