Formation of S0 galaxies through mergers. Bulge-disc structural coupling resulting from major mergers
arXiv:1409.5126 · doi:10.1051/0004-6361/201424303
Abstract
Observations reveal a strong structural coupling between bulge and disc in S0 galaxies, which seems difficult to explain if they have formed from supposedly catastrophic events such as major mergers. We face this question by quantifying the bulge-disc coupling in dissipative simulations of major and minor mergers that result in realistic S0s. We have studied the dissipative N-body binary merger simulations from the GalMer database that give rise to realistic, relaxed E/S0 and S0 remnants (67 major and 29 minor mergers). We simulate surface brightness profiles of these S0-like remnants in the K-band, mimicking typical observational conditions, to perform bulge-disc decompositions analogous to those carried out in real S0s. The global bulge-disc structure of these remnants has been compared with real data, and they distribute in the B/T - r_e - h_d parameter space consistently with real bright S0s, where B/T is the bulge-to-total luminosity ratio, r_e is the bulge effective radius, and h_d is the disc scalelength. Major mergers can rebuild a bulge-disc coupling in the remnants after having destroyed the structures of the progenitors, whereas minor mergers directly preserve them. Remnants exhibit B/T and r_e/h_d spanning a wide range of values, and their distribution is consistent with observations. Many remnants have bulge Sersic indices ranging 1<n<2, flat appearance, and contain residual star formation in embedded discs, a result which agrees with the presence of pseudobulges in real S0s. Contrary to the popular view, mergers (and in particular, major events) can result in S0 remnants with realistically coupled bulge-disc structures in less than ~3 Gyr. In conclusion, the bulge-disc coupling and the presence of pseudobulges in real S0s cannot be used as an argument against the possible major-merger origin of these galaxies.
23 pages, accepted for publication in Astronomy and Astrophysics (version after minor language corrections)
References in corpus (19)
- Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
- From rings to bulges: evidence for rapid secular galaxy evolution at z~2 from integral field spectroscopy in the SINS survey
- Galaxy Zoo: the dependence of morphology and colour on environment
- Structural Properties of Pseudo-Bulges, Classical Bulges and Elliptical Galaxies: an SDSS Perspective
- Star formation efficiency in galaxy interactions and mergers: a statistical study
- On the frequency, intensity and duration of starburst episodes triggered by galaxy interactions and mergers
- Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks
- 2-Dimensional Kinematics of Simulated Disc Merger Remnants
- Ram-pressure stripped molecular gas in the Virgo spiral galaxy NGC 4522
- The Near-infrared S0 Survey III: Morphology of 15 Southern Early-type Disk Galaxies
- Galaxy Evolution in Hickson Compact Groups: The Role of Ram Pressure Stripping and Strangulation
- Growth of galactic bulges by mergers. II. Low-density satellites
- Bars, ovals and lenses in early-type disk galaxies: probes of galaxy evolution
- The Stellar Populations of Stripped Spiral Galaxies in the Virgo Cluster
- Ram pressure stripping of the multiphase ISM in the Virgo cluster spiral galaxy NGC 4438
- Formation of S0 galaxies through mergers. V. Antitruncated stellar discs resulting from major mergers
- Measuring the fading of S0 galaxies using globular clusters
- A forming disk at z~0.6: Collapse of a gaseous disk or major merger remnant?
- The Evolution of Field Early-Type Galaxies in the FDF and WHDF