Images - II. A surprisingly low fraction of undisturbed rotating spiral disks at z similar to 0.6 The morpho-kinematical relation 6 Gyr ago
Title | Images - II. A surprisingly low fraction of undisturbed rotating spiral disks at z similar to 0.6 The morpho-kinematical relation 6 Gyr ago |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Neichel, 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 |
Journal | Astronomy & Astrophysics |
Volume | 484 |
Pagination | 159-U59 |
Date Published | Jun |
ISBN Number | 0004-6361 |
Accession Number | WOS:000256309400016 |
Abstract | 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. |