Deep Very Large TelescopeV‐Band Imaging of the Field of az= 10 Candidate Galaxy: Below the Lyman Limit?

We present a deep 16.8 ks V-band image of the field of a candidate z=10galaxy magnified by the foreground (z=0.25) cluster A1835. The image wasobtained with FORS1 on VLT-Kueyen to test whether the V-band lies below theLyman limit for this very high redshift candidate. A detection wouldunambiguously rule out that the source is at z=10. The 3sigma detection limitof the image in the area of the z=10 candidate is V_AB=28.0 mag in a 2 arcsecdiameter aperture (about 3 times the seeing FWHM of 0.7 arcsec). No source atthe position of the candidate galaxy is detected down to this limit. Formally,this is consistent with the V-band probing below the Lyman limit in therest-frame of a z=10 source. However, given the recent non-detection of theobject in a deep H-band exposure with NIRI on Gemini North down to H_AB=26.0mag (3sigma in a 1.4 arcsec aperture) and concerns about the detection of thereported associated emission line, it may be possible that this source isspurious. We discuss several astrophysical possibilities to explain thepuzzling nature of this source and find none of them compelling.Comment: accepted for publication in Ap