We present a strong lensing mass model of Abell 1689 which resolves substructures \sim 25 kpc across ( including about ten individual galaxy subhalos ) within the central \sim 400 kpc diameter .
We achieve this resolution by perfectly reproducing the observed ( strongly lensed ) input positions of 168 multiple images of 55 knots residing within 135 images of 42 galaxies .
Our model makes no assumptions about light tracing mass , yet we reproduce the brightest visible structures with some slight deviations .
A1689 remains one of the strongest known lenses on the sky , with an Einstein radius of R _ { E } = 47.0 \arcsec \pm 1.2 \arcsec ( 143 ^ { +3 } _ { -4 } kpc ) for a lensed source at z _ { s } = 2 .
We find a single NFW or Sérsic profile yields a good fit simultaneously ( with only slight tension ) to both our strong lensing ( SL ) mass model and published weak lensing ( WL ) measurements at larger radius ( out to the virial radius ) .
According to this NFW fit , A1689 has a mass of M _ { vir } = 2.0 ^ { +0.5 } _ { -0.3 } \times 10 ^ { 15 } M _ { \odot } h _ { 70 } ^ { -1 } ( M _ { 200 } = 1.8 ^ { +0.4 } _ { -0.3 } \times 10 ^ { 15 } M _ { \odot } h _ { 70 } ^ { -1 } ) within the virial radius r _ { vir } = 3.0 \pm 0.2 ~ { } { Mpc } ~ { } h _ { 70 } ^ { -1 } ( r _ { 200 } = 2.4 ^ { +0.1 } _ { -0.2 } ~ { } { Mpc } ~ { } h _ { 70 } ^ { -1 } ) , and a central concentration c _ { vir } = 11.5 ^ { +1.5 } _ { -1.4 } ( c _ { 200 } = 9.2 \pm 1.2 ) .
Our SL model prefers slightly higher concentrations than previous SL models , bringing our SL+WL constraints in line with other recent derivations .
Our results support those of previous studies which find A1689 has either an anomalously large concentration or significant extra mass along the line of sight ( perhaps in part due to triaxiality ) .
If clusters are generally found to have higher concentrations than realized in simulations , this could indicate they formed earlier , perhaps as a result of early dark energy .