Detalles de publicación
PP 017059
Evolution of the anti-truncated stellar profiles of S0 galaxies since z=0.6 in the SHARDS survey: I - Sample and Methods
1. IAC, 2. Dept. Astrofísica y CC. U. Complutense de Madrid, 3. Dept. Astrofísica ULL 4. CSIC 5. Centre Astrophysics & Supercomputing, U. Swinburne (Australia), 6.U.California, Berkeley, 7. Observatoire de Genève, Suiza 8. IFCA-CSIC.
Context. The controversy about the origin of the structure of early-type S0–E/S0 galaxies may be due to the difficulty of comparing
surface brightness profiles with different depths, photometric corrections and PSF effects (almost always ignored).
Aims. We aim to quantify the properties of Type-III (anti-truncated) discs in a sample of S0 galaxies at 0.2 < z < 0.6. In this paper,
we present the sample selection and describe in detail the methods to robustly trace the structure in their outskirts and correct for PSF
effects.
Methods. We have selected and classified a sample of 150 quiescent galaxies at 0.2 < z < 0.6 in the GOODS-N field. We perform
a quantitative structural analysis of 44 S0–E/S0 galaxies. We have corrected their surface brightness profiles for PSF distortions
and analysed the biases in the structural and photometric parameters when the PSF correction is not applied. Additionally, we have
developed Elbow, an automatic statistical method to determine whether a possible break is significant - or not - and its type and made
it publicly available.
Results. We found 14 anti-truncated S0–E/S0 galaxies in the range 0.2 < z < 0.6 (∼ 30% of the final sample). This fraction is similar
to the those reported in the local Universe. In our sample, ∼ 25% of the Type-III breaks observed in PSF-uncorrected profiles are
artifacts, and their profiles turn into a Type I after PSF correction. PSF effects also soften Type-II profiles. We found that the profiles
of Type-I S0 and E/S0 galaxies of our sample are compatible with the inner profiles of the Type-III, in contrast with the outer profiles.
Conclusions. We have obtained the first robust and reliable sample of 14 anti-truncated S0–E/S0 galaxies beyond the local Universe,
in the range 0.2 < z < 0.6. PSF effects significantly affect the shape of the surface brightness profiles in galaxy discs even in the case
of the narrow PSF of HST/ACS images, so future studies on the subject should make an effort to correct them
surface brightness profiles with different depths, photometric corrections and PSF effects (almost always ignored).
Aims. We aim to quantify the properties of Type-III (anti-truncated) discs in a sample of S0 galaxies at 0.2 < z < 0.6. In this paper,
we present the sample selection and describe in detail the methods to robustly trace the structure in their outskirts and correct for PSF
effects.
Methods. We have selected and classified a sample of 150 quiescent galaxies at 0.2 < z < 0.6 in the GOODS-N field. We perform
a quantitative structural analysis of 44 S0–E/S0 galaxies. We have corrected their surface brightness profiles for PSF distortions
and analysed the biases in the structural and photometric parameters when the PSF correction is not applied. Additionally, we have
developed Elbow, an automatic statistical method to determine whether a possible break is significant - or not - and its type and made
it publicly available.
Results. We found 14 anti-truncated S0–E/S0 galaxies in the range 0.2 < z < 0.6 (∼ 30% of the final sample). This fraction is similar
to the those reported in the local Universe. In our sample, ∼ 25% of the Type-III breaks observed in PSF-uncorrected profiles are
artifacts, and their profiles turn into a Type I after PSF correction. PSF effects also soften Type-II profiles. We found that the profiles
of Type-I S0 and E/S0 galaxies of our sample are compatible with the inner profiles of the Type-III, in contrast with the outer profiles.
Conclusions. We have obtained the first robust and reliable sample of 14 anti-truncated S0–E/S0 galaxies beyond the local Universe,
in the range 0.2 < z < 0.6. PSF effects significantly affect the shape of the surface brightness profiles in galaxy discs even in the case
of the narrow PSF of HST/ACS images, so future studies on the subject should make an effort to correct them