SPT-CL J2032-5627: a new Southern double relic cluster observed with ASKAP. (arXiv:2008.00660v1 [astro-ph.GA])

SPT-CL J2032-5627: a new Southern double relic cluster observed with ASKAP. (arXiv:2008.00660v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Duchesne_S/0/1/0/all/0/1">S. W. Duchesne</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Johnston_Hollitt_M/0/1/0/all/0/1">M. Johnston-Hollitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bartalucci_I/0/1/0/all/0/1">I. Bartalucci</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hodgson_T/0/1/0/all/0/1">T. Hodgson</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Pratt_G/0/1/0/all/0/1">G. W. Pratt</a>

We present a radio and X-ray analysis of the galaxy cluster SPT-CL
J2032-5627. Investigation of public data from the Australian Square Kilometre
Array Pathfinder (ASKAP) at 943 MHz shows two previously undetected radio
relics at either side of the cluster. For both relic sources we utilise
archival Australia Telescope Compact Array (ATCA) data at 5.5 GHz in
conjunction with the new ASKAP data to determine that both have steep
integrated radio spectra ($alpha_mathrm{SE} = -1.33 pm 0.10$ and
$alpha_mathrm{NW,full} = -1.16 pm 0.12$ for the southeast and northwest
relic sources, respectively). No shock is seen in XMM-Newton observations,
however, the southeast relic is preceded by a cold front in the X-ray emitting
intra-cluster medium. We suggest the lack of detectable shock may be due to
instrumental limitations, comparing the situation to the southeast relic in
Abell 3667. We compare the relics to the population of double relic sources and
find they are located below the current power-mass ($P$-$M$) scaling relation.
We present an analysis of the low-surface brightness sensitivity of ASKAP and
the ATCA, the excellent sensitivity of both allow the ability to find
heretofore undetected diffuse sources, suggesting these low-power radio relics
will become more prevalent in upcoming large-area radio surveys such as the
Evolutionary Map of the Universe (EMU).

We present a radio and X-ray analysis of the galaxy cluster SPT-CL
J2032-5627. Investigation of public data from the Australian Square Kilometre
Array Pathfinder (ASKAP) at 943 MHz shows two previously undetected radio
relics at either side of the cluster. For both relic sources we utilise
archival Australia Telescope Compact Array (ATCA) data at 5.5 GHz in
conjunction with the new ASKAP data to determine that both have steep
integrated radio spectra ($alpha_mathrm{SE} = -1.33 pm 0.10$ and
$alpha_mathrm{NW,full} = -1.16 pm 0.12$ for the southeast and northwest
relic sources, respectively). No shock is seen in XMM-Newton observations,
however, the southeast relic is preceded by a cold front in the X-ray emitting
intra-cluster medium. We suggest the lack of detectable shock may be due to
instrumental limitations, comparing the situation to the southeast relic in
Abell 3667. We compare the relics to the population of double relic sources and
find they are located below the current power-mass ($P$-$M$) scaling relation.
We present an analysis of the low-surface brightness sensitivity of ASKAP and
the ATCA, the excellent sensitivity of both allow the ability to find
heretofore undetected diffuse sources, suggesting these low-power radio relics
will become more prevalent in upcoming large-area radio surveys such as the
Evolutionary Map of the Universe (EMU).

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