Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Lessons learned from the two largest Galaxy morphological classification catalogues built by convolutional neural networks
AU - Dark Energy Survey Collaboration
AU - Cheng, T. -Y.
AU - Domínguez Sánchez, H.
AU - Vega-Ferrero, J.
AU - Conselice, C. J.
AU - Siudek, M.
AU - Aragón-Salamanca, A.
AU - Bernardi, M.
AU - Cooke, R.
AU - Ferreira, L.
AU - Huertas-Company, M.
AU - Krywult, J.
AU - Palmese, A.
AU - Pieres, A.
AU - Plazas Malagón, A. A.
AU - Carnero Rosell, A.
AU - Gruen, D.
AU - Thomas, D.
AU - Bacon, D.
AU - Brooks, D.
AU - James, D. J.
AU - Hollowood, D. L.
AU - Friedel, D.
AU - Suchyta, E.
AU - Sanchez, E.
AU - Menanteau, F.
AU - Paz-Chinchón, F.
AU - Gutierrez, G.
AU - Tarle, G.
AU - Sevilla-Noarbe, I.
AU - Ferrero, I.
AU - Annis, J.
AU - Frieman, J.
AU - García-Bellido, J.
AU - Mena-Fernández, J.
AU - Honscheid, K.
AU - Kuehn, K.
AU - da Costa, L. N.
AU - Gatti, M.
AU - Raveri, M.
AU - Pereira, M. E. S.
AU - Rodriguez-Monroy, M.
AU - Smith, M.
AU - Carrasco Kind, M.
AU - Aguena, M.
AU - Swanson, M. E. C.
AU - Weaverdyck, N.
AU - Doel, P.
AU - Miquel, R.
AU - Ogando, R. L. C.
AU - Gruendl, R. A.
PY - 2023/1/31
Y1 - 2023/1/31
N2 - We compare the two largest galaxy morphology catalogues, which separate early- and late-type galaxies at intermediate redshift. The two catalogues were built by applying supervised deep learning (convolutional neural networks, CNNs) to the Dark Energy Survey data down to a magnitude limit of ~21 mag. The methodologies used for the construction of the catalogues include differences such as the cutout sizes, the labels used for training, and the input to the CNN - monochromatic images versus gri-band normalized images. In addition, one catalogue is trained using bright galaxies observed with DES (i < 18), while the other is trained with bright galaxies (r < 17.5) and 'emulated' galaxies up to r-band magnitude 22.5. Despite the different approaches, the agreement between the two catalogues is excellent up to i < 19, demonstrating that CNN predictions are reliable for samples at least one magnitude fainter than the training sample limit. It also shows that morphological classifications based on monochromatic images are comparable to those based on gri-band images, at least in the bright regime. At fainter magnitudes, i > 19, the overall agreement is good (~95 per cent), but is mostly driven by the large spiral fraction in the two catalogues. In contrast, the agreement within the elliptical population is not as good, especially at faint magnitudes. By studying the mismatched cases, we are able to identify lenticular galaxies (at least up to i < 19), which are difficult to distinguish using standard classification approaches. The synergy of both catalogues provides an unique opportunity to select a population of unusual galaxies....
AB - We compare the two largest galaxy morphology catalogues, which separate early- and late-type galaxies at intermediate redshift. The two catalogues were built by applying supervised deep learning (convolutional neural networks, CNNs) to the Dark Energy Survey data down to a magnitude limit of ~21 mag. The methodologies used for the construction of the catalogues include differences such as the cutout sizes, the labels used for training, and the input to the CNN - monochromatic images versus gri-band normalized images. In addition, one catalogue is trained using bright galaxies observed with DES (i < 18), while the other is trained with bright galaxies (r < 17.5) and 'emulated' galaxies up to r-band magnitude 22.5. Despite the different approaches, the agreement between the two catalogues is excellent up to i < 19, demonstrating that CNN predictions are reliable for samples at least one magnitude fainter than the training sample limit. It also shows that morphological classifications based on monochromatic images are comparable to those based on gri-band images, at least in the bright regime. At fainter magnitudes, i > 19, the overall agreement is good (~95 per cent), but is mostly driven by the large spiral fraction in the two catalogues. In contrast, the agreement within the elliptical population is not as good, especially at faint magnitudes. By studying the mismatched cases, we are able to identify lenticular galaxies (at least up to i < 19), which are difficult to distinguish using standard classification approaches. The synergy of both catalogues provides an unique opportunity to select a population of unusual galaxies....
U2 - 10.1093/mnras/stac3228
DO - 10.1093/mnras/stac3228
M3 - Journal article
VL - 518
SP - 2794
EP - 2809
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -