Context : The mechanisms giving rise to diffuse radio emission in galaxy clusters , and in particular their connection with cluster mergers , are still debated .

Aims : We seek to explore the internal dynamics of the radio halo cluster Abell 545 .
This cluster is also peculiar for hosting in its center a very bright , red , diffuse intracluster light due to an old , stellar population , so bright to be named as “ star pile ” .

Methods : Our analysis is mainly based on redshift data for 110 galaxies .
We identify 95 cluster members and analyze the cluster internal dynamics by combining galaxy velocities and positions .
We also use both photometric and X-ray data .

Results : We estimate the cluster redshift , \left < z \right > = 0.1580 , a large line-of-sight ( LOS ) velocity dispersion \sigma _ { V } \sim 1200 km s ^ { -1 } , and ICM temperature kT _ { X } \sim 8 keV .
Our optical and X-ray analyses detect substructures .
Optical data reveal three main galaxy clumps ( one at the center hosting the peak of X-ray emission ; one at NNW , and one at NE ) ; and possibly a fourth clump at South .
There is not a dominant galaxy and the four brightest galaxies avoid the cluster core – \gtrsim 0.4 h _ { 70 } ^ { -1 } Mpc distant from the cluster center – and are \gtrsim 1500 km s ^ { -1 } far from the mean cluster velocity .
The analysis of the X-ray surface brightness distribution provides us evidence of a disturbed dynamical phase with a likely signature of a shock .
Located in the star pile region there is the brightest galaxy of the cluster core ( CBCG ) and a very compact elliptical galaxy .
We show that the star pile , which has a previously determined redshift , has a similar redshift to that of the CBCG .
Both the star pile and the CBCG are at rest in the cluster rest frame .
The elongation of the star pile and its relative position with respect to the CBCG indicate the same direction pointed out by the NE clump .

Conclusions : The emerging picture of Abell 545 is that of a massive , M ( R < 1.6 h _ { 70 } ^ { -1 } \mathrm { Mpc } ) = ( 1.1 – 1.8 ) \times 10 ^ { 15 } h _ { 70 } ^ { -1 } M _ { \odot } , very complex cluster with merging occurring along two directions .
Abell 545 gives another proof in the favor of the connection between cluster merger and extended , diffuse radio emission .
The star pile , likely due to the process of a brightest galaxy forming in the cluster core .
Abell 545 represents a textbook cluster where to study the simultaneous formation of a galaxy system and its brightest galaxy .