Context : The Galactic Center offers unique opportunities to study stellar and bow-shock polarization effects in a dusty environment .

Aims : The goals of this work are to provide near-infrared ( NIR ) polarimetry of the stellar sources in the central parsec at the resolution of an 8m telescope for the first time , along with new insights into the nature of the known bright bow-shock sources .

Methods : We use adaptive-optics assisted observations obtained at the ESO VLT in the H- and Ks-band , applying both high-precision photometric methods specifically developed for crowded fields and a newly established polarimetric calibration for NACO to produce polarization maps of the central 3 ” \times 19 ” , in addition to spatially resolved polarimetry and a flux variability analysis on the extended sources in this region .

Results : We find foreground polarization mainly parallel to the Galactic plane , with average values of ( 4.6 \pm 0.6 ) % at 26 ^ { \circ } \pm 6 ^ { \circ } ( Ks-band ) and ( 9.3 \pm 1.3 ) % at 20 ^ { \circ } \pm 6 ^ { \circ } ( H-band ) in the center of the field-of-view ( FOV ) .
Further away from the center , we find higher polarization degrees and steeper polarization angles : ( 7.5 \pm 1.0 ) % at 11 ^ { \circ } \pm 6 ^ { \circ } ( Ks-band ) and ( 12.1 \pm 2.1 ) % at 13 ^ { \circ } \pm 6 ^ { \circ } ( H-band ) . p _ { H } / p _ { Ks } peaks at 1.9 \pm 0.4 , corresponding to a power law index for the wavelength dependency of \alpha = 2.4 \pm 0.7 .
These values also vary over the FOV , with higher values in the center .
This is indicative of the influence of local effects on the total polarization , possibly dichroic extinction by Northern Arm dust .
The two extended sources IRS 21 and 1W show similar intrinsic polarization degrees of 6.1 resp .
7.8 % ( Ks ) and 6.9 ( H , only 1W ) at polarization angles coincident with previous NIR and mid-infrared ( MIR ) findings , both in total and spatially resolved .
The spatial polarization pattern of both sources points to scattering on aligned elongated dust grains as the major source of intrinsic polarization , and matches the known orientation of the magnetic field .
Our data also allow us to separate the bow shock of IRS 21 from the central source for the first time in the Ks-band , finding the apex north of the central source and determining a standoff distance of \sim 400 AU , which matches previous estimates .
This source also shows a \sim 50 % increase in flux in the NIR over several years .

Conclusions :