Formation of slowly rotating early-type galaxies via major mergers: a resolution study

被引：57

作者：

Bois, M. ^{[1
,2
,3
]}

Bournaud, F. ^{[4
,5
]}

Emsellem, E. ^{[1
,2
,3
]}

Alatalo, K. ^{[6
,7
]}

Blitz, L. ^{[6
,7
]}

Bureau, M. ^{[8
]}

Cappellari, M. ^{[8
]}

Davies, R. L. ^{[8
]}

Davis, T. A. ^{[8
]}

de Zeeuw, P. T. ^{[3
,9
]}

Duc, P. -A. ^{[4
,5
]}

Khochfar, S. ^{[10
]}

Krajnovic, D. ^{[3
]}

Kuntschner, H. ^{[11
]}

Lablanche, P. -Y. ^{[1
,2
]}

McDermid, R. M. ^{[12
]}

Morganti, R. ^{[13
]}

Naab, T. ^{[14
,15
]}

Oosterloo, T. ^{[13
]}

Sarzi, M. ^{[16
]}

Scott, N. ^{[8
]}

Serra, P. ^{[13
]}

Weijmans, A. ^{[17
]}

Young, L. M. ^{[18
]}

机构：

[1] Univ Lyon 1, Observ Lyon, Ctr Rech Astrophys Lyon, F-69230 St Genis Laval, France

[2] Ecole Natl Super Lyon, F-69230 St Genis Laval, France

[3] European So Observ, D-85748 Garching, Germany

[4] Univ Paris Diderot, CNRS, Lab AIM, CEA Saclay, F-91191 Gif Sur Yvette, France

[5] Univ Paris Diderot, CEA, IRFU, SAp, F-91191 Gif Sur Yvette, France

[6] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA

[7] Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA

[8] Univ Oxford, Oxford OX1 3RH, England

[9] Leiden Univ, NL-2300 RA Leiden, Netherlands

[10] Max Planck Inst Extraterr Phys, D-85748 Garching, Germany

[11] European So Observ, Space Telescope European Coordinating Facil, D-85748 Garching, Germany

[12] No Operat Ctr, Gemini Observ, Hilo, HI 96720 USA

[13] Netherlands Fdn Res Astron ASTRON, NL-7990 AA Dwingeloo, Netherlands

[14] Univ Sternwarte Munchen, D-81679 Munich, Germany

[15] Max Planck Inst Astrophys, D-85741 Garching, Germany

[16] Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL1 09AB, Herts, England

[17] Univ Toronto, Dunlap Inst Astron & Astrophys, Toronto, ON M5S 3H4, Canada

[18] New Mexico Inst Min & Technol, Dept Phys, Socorro, NM 87801 USA

来源：

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY | 2010年 / 406卷 / 04期

关键词：

galaxies: elliptical and lenticulars; cD; galaxies: formation; galaxies: interactions; galaxies: kinematics and dynamics; SAURON PROJECT; KINEMATIC PROPERTIES; STAR-FORMATION; EQUAL-MASS; GAS-RICH; REMNANTS; ORIGIN; TRANSFORMATIONS; SIMULATIONS; DISSIPATION;

D O I：

10.1111/j.1365-2966.2010.16885.x

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We study resolution effects in numerical simulations of gas-rich and gas-poor major mergers, and show that the formation of slowly rotating elliptical galaxies often requires a resolution that is beyond the present-day standards to be properly modelled. Our sample of equal-mass merger models encompasses various masses and spatial resolutions, ranging from about 200 pc and 105 particles per component (stars, gas and dark matter), i.e. a gas mass resolution of similar to 105 M-circle dot, typical of some recently published major merger simulations, to up to 32 pc and similar to 103 M-circle dot in simulations using 2.4 x 107 collisionless particles and 1.2 x 107 gas particles, among the highest resolutions reached so far for gas-rich major merger of massive disc galaxies. We find that the formation of fast-rotating early-type galaxies, that are flattened by a significant residual rotation, is overall correctly reproduced at all such resolutions. However, the formation of slow-rotating early-type galaxies, which have a low-residual angular momentum and are supported mostly by anisotropic velocity dispersions, is strongly resolution-dependent. The evacuation of angular momentum from the main stellar body is largely missed at standard resolution, and systems that should be slow rotators are then found to be fast rotators. The effect is most important for gas-rich mergers, but is also witnessed in mergers with an absent or modest gas component (0-10 per cent in mass). The effect is robust with respect to our initial conditions and interaction orbits, and originates in the physical treatment of the relaxation process during the coalescence of the galaxies. Our findings show that a high-enough resolution is required to accurately model the global properties of merger remnants and the evolution of their angular momentum. The role of gas-rich mergers of spiral galaxies in the formation of slow-rotating ellipticals may therefore have been underestimated. Moreover, the effect of gas in a galaxy merger is not limited to helping the survival/rebuilding of rotating disc components: at high resolution, gas actively participates in the relaxation process and the formation of slowly rotating stellar systems.

引用

页码：2405 / 2420

页数：16

共 45 条

[1] Transformations of galaxies .2. Gasdynamics in merging disk galaxies [J].