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Images - II. A surprisingly low fraction of undisturbed rotating spiral disks at z similar to 0.6 The morpho-kinematical relation 6 Gyr ago

TitreImages - II. A surprisingly low fraction of undisturbed rotating spiral disks at z similar to 0.6 The morpho-kinematical relation 6 Gyr ago
Type de publicationJournal Article
Year of Publication2008
AuteursNeichel, B, Hammer, F, Puech, M, Flores, H, Lehnert, M, Rawat, A, Yang, Y, Delgado, R, Amram, P, Balkowski, C, Cesarsky, C, Dannerbauer, H, Fuentes-Carrera, I, Guiderdoni, B, Kembhavi, A, Liang, YC, Nesvadba, N, Ostlin, G, Pozzetti, L, Ravikumar, CD, Alighieri, SD, Vergani, D, Vernet, J, Wozniak, H
JournalAstronomy & Astrophysics
Volume484
Pagination159-U59
Date PublishedJun
ISBN Number0004-6361
Numéro d'accèsWOS:000256309400016
Résumé

We present a first combined analysis of the morphological and dynamical properties for the intermediate-mass Galaxy Evolution Sequence ( IMAGES) sample. It is a representative sample of 52 z similar to 0.6 galaxies with M(stell) from 1.5 to 15 x 10(10) M(circle dot) that possesses 3D resolved kinematics and HST deep imaging in at least two broad band filters. We aim at evaluating the evolution of rotating spirals robustly since z similar to 0.6, as well as at testing the different schemes for classifying galaxies morphologically. We used all the information provided by multi-band images, color maps, and 2D light fitting to assign a morphological class to each object. We divided our sample into spiral disks, peculiar objects, compact objects, and mergers. Using our morphological classification scheme, 4/5 of the identified spirals are rotating disks, and more than 4/5 of identified peculiar galaxies show complex kinematics, while automatic classification methods such as concentration-asymmetry and GINI-M20 severely overestimate the fraction of relaxed disk galaxies. Using this methodology, we find that the fraction of undisturbed rotating spirals has increased by a factor similar to 2 during the past 6 Gyr, a much higher fraction than was found previously based on morphologies alone. These rotating spiral disks are forming stars very rapidly, even doubling their stellar masses over the past 6 Gyr, while most of their stars were formed a few Gyr earlier, which reveals a large gas supply. Because they are the likely progenitors of local spirals, we can conjecture how their properties are evolving. Their disks show some evidence of inside-out growth, and the gas supply/accretion is not random since the disk needs to be stable in order to match the local disk properties.

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