We present results from Chandra , XMM- Newton , and ROSAT observations of the Planck SZ-detected cluster A3716 ( PLCKG345.40-39.34 – G345 ) .
We show that G345 is , in fact , two subclusters separated on the sky by 400 kpc .
We measure the subclusters ’ gas temperatures ( \sim 2–3 keV ) , total ( \sim 1–2 \times 10 ^ { 14 } ~ { } M _ { \odot } ) and gas ( \sim 1–2 \times 10 ^ { 13 } ~ { } M _ { \odot } ) masses , gas mass fraction within r _ { 500 } , entropy profiles , and X-ray luminosities ( \sim 10 ^ { 43 } ~ { } erg~ { } s ^ { -1 } ) .
Using the gas density and temperature profiles for both subclusters , we show that there is good ( 0.8 \sigma ) agreement between the expected Sunyaev-Zel ’ dovich signal predicted from the X-ray data and that measured from the Planck mission , and better agreement within 0.6 \sigma when we re-computed the Planck value assuming a two component cluster model , with relative amplitudes fixed based on the X-ray data .
Dynamical analysis shows that the two galaxy subclusters are very likely ( > 97 \% probability ) gravitationally bound , and in the most likely scenario , the subclusters will undergo core passage in 500 \pm 200 Myr .
The northern subcluster is centrally peaked and has a low entropy core , while the southern subcluster has a high central entropy .
The high central entropy in the southern subcluster can be explained either by the mergers of several groups , as suggested by the presence of five giant ellipticals or by AGN energy injection , as suggested by the presence of a strong radio source in one of its massive elliptical galaxies , or by a combination of both processes .