We report optical B-band observations with the Large Binocular Telescope LBT of the isolated neutron star RBS1774 .
The stacked image with total exposure 2 \aas@@fstack { h } 5 reveals a candidate optical counterpart at m _ { B } = 26.96 \pm 0.20 at position \alpha { ( 2000 ) } = 21 ^ { h } 43 ^ { m } 03 \aas@@fstack { s } 40 , \delta { ( 2000 ) } = +06 \degr 54 ^ { \prime } 17 \aas@@fstack { \prime \prime } 5 , within the joint Chandra and XMM-Newton error circles .
We analyse archival XMM-Newton observations and derive revised spectral and positional parameters .
The predicted optical flux from the extrapolated X-ray spectrum is likely twice as high as reported before .
The measured optical flux exceeds the extrapolated X-ray spectral flux by a factor \sim 40 ( 15 – 60 at 1 \sigma confidence ) .
We interpret our detection and the spectral energy distribution as further evidence of a temperature structure over the neutron star ’ s surface and present a pure thermal model reflecting both the SED and the pulsed fraction of the light curve .