Evolution of the anti-truncated stellar profiles of S0 galaxies since z=0.6 in the SHARDS survey

Abstract

Lenticular galaxies (S0s) are more likely to host anti-truncated (Type III) stellar discs than galaxies of later Hubble types. Previous work on Type-III S0s at z = 0 revealed that the characteristic parameters of the breaks obey tight scaling relations (Borlaff et al. 2014). These relation are similar in both S0’s and spirals, in optical and NIR, and for barred and non-barred galaxies (Eliche-Moral et al. 2015). We have analysed 3DHST images (Brammer et al. 2012) of S0 galaxies from the SHARDS survey (Pérez-González et al. 2013) in order to investigate if E/S0 and S0 galaxies with anti-truncated stellar profiles up to z ~ 0.6 follow similar scaling relations compared to the local sample. We find that the characteristic photometric parameters of Type-III S0s at 0.4 < z < 0.6 obey analogous scaling relations to those observed in their local counterparts, lying on top of the extrapolations of the local trends towards brighter magnitudes in several photometric diagrams and sharing similar trends and values in the h_i – R_brkIII, h_o – R_brkIII and h_i – h_o diagrams. We have measured the offsets in magnitudes between two subsets of the z ~ 0.5 and z = 0 samples with similar masses (log ₁₀M/M_⊙ ~ 10.7). The median offsets are: Δμ_brkIII = − 2.23^+0.46_−0.62, Δμ_{0, i} = − 2.61^+0.31_−0.26 and Δμ_{0, o} = − 2.31^+0.57_−0.78 mag arcsec^-2. We find that PSF corrections in our images do not significantly affect the scaling relations obtained in our 0.2 < z < 0.6 sample. In conclusion, the existence of similar scaling relations in Type-III S0 discs since z ~ 0.6 implies that the structures of the inner and outer discs in anti-truncated S0s have been similarly linked in the last ~ 6 Gyr, posing strong constraints to the processes proposed to explain their formation.