Context : X-ray observations reveiled a group of radio-silent isolated neutron stars ( INSs ) at the centre of young supernova remnants ( SNRs ) , dubbed central compact objects or CCOs , with properties different from those of classical rotation-powered pulsars .
In at least three cases , evidence points towards CCOs being low-magnetized INSs , born with slow rotation periods , and possibly accreting from a debris disc of material formed out of the supernova event .
Understanding the origin of the diversity of the CCOs can shed light on supernova explosion and neutron star formation models .
Optical/infrared ( IR ) observations are crucial to test different CCO interpretations .

Aims : The aim of our work is to perform a deep optical investigation of the CCO RX J0822.0 - 4300 in the Puppis A SNR , one of the most poorly understood in the CCO family .

Methods : By using as a reference the Chandra X-ray coordinates of RX J0822.0 - 4300 we performed deep optical observations in the B , V and I bands with the Very Large Telescope ( VLT ) .

Results : We found no candidate optical counterpart within 3 \sigma of the computed Chandra X-ray position down to 5 \sigma limits of B \sim 27.2 , V \sim 26.9 , and I \sim 25.6 , the deepest obtained in the optical band for this source .

Conclusions : These limits confirm the non-detection of a companion brighter than an M5 dwarf .
At the same time , they do not constrain optical emission from the neutron star surface , while emission from the magnetosphere would require a spectral break in the optical/IR .