The galaxy cluster Abell 1644 ( \bar { z } = 0.047 ) is known for its remarkable spiral-like X-ray emission .
It was previously identified as a bimodal system , comprising the subclusters , A1644S and A1644N , each one centred on a giant elliptical galaxy .
In this work , we present a comprehensive study of this system , including new weak lensing and dynamical data and analysis plus a tailor-made hydrodynamical simulation .
The lensing and galaxy density maps showed a structure in the North that could not be seen on the X-ray images .
We , therefore , rename the previously known northern halo as A1644N1 and the new one as A1644N2 .
Our lensing data suggest that those have fairly similar masses : M _ { 200 } ^ { N 1 } = 0.90 _ { -0.85 } ^ { +0.45 } \times 10 ^ { 14 } and M _ { 200 } ^ { N 2 } = 0.76 _ { -0.75 } ^ { +0.37 } \times 10 ^ { 14 } M _ { \odot } , whereas the southern structure is the main one : M _ { 200 } ^ { S } = 1.90 _ { -1.28 } ^ { +0.89 } \times 10 ^ { 14 } M _ { \odot } .
Based on the simulations , fed by the observational data , we propose a scenario where the remarkable X-ray characteristics in the system are the result of a collision between A1644S and A1644N2 that happened \sim 1.6 Gyr ago .
Currently , those systems should be heading to a new encounter , after reaching their maximum separation .