Kinematic imprint of clumpy disk formation on halo objects

Abstract

Context: Clumpy disk galaxies in the distant universe, at redshift of z>1, have been observed to host several giant clumps in their disks. They are thought to correspond to early formative stages of disk galaxies. On the other hand, halo objects, such as old globular clusters and halo stars, are likely to consist of the oldest stars in a galaxy (age>10 Gyr), therefore the clumpy disk formation can be presumed to take place in a pre-existing halo system. Aims: Giant clumps are orbiting in the same direction in a premature disk and so massive that they may be expected to interact gravitationally with halo objects and exercise influence on kinematic state of the halo. Accordingly, I scrutinize the possibility that the clumps leave a kinematic imprint of the clumpy disk formation on a halo system. Methods: I perform a restricted N-body calculation with a toy-model to study the kinematic influence on a halo by orbital motions of clumps, examine dependence of the results on masses (mass-loss), number and orbital radii of the clumps. Results: I will show that halo objects can catch clump motions and acquire disky rotation in a dynamical friction time-scale of the clumps, ~0.5 Gyr. The influence of clumps is limited within a region around the disk, the halo system shows vertical gradients of net rotation velocity and orbital eccentricity. The significance of the kinematic influence strongly depends on the clump masses, the lower limit of postulated clump mass would be 5x10^8 solar masses. The result depends also on whether the clumps are subjected to rapid mass-loss or not, which is an open question under debate in recent studies. The existence of such massive clumps is not unrealistic, I therefore suggest that there could remain the imprints of past clumpy disk formation in current galactic halos.

8 pages, 10 figures, accepted for publication in A&A, minor corrections made

References in corpus (17)

• Cold streams in early massive hot haloes as the main mode of galaxy formation
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• From rings to bulges: evidence for rapid secular galaxy evolution at z~2 from integral field spectroscopy in the SINS survey
• Two Stellar Components in the Halo of the Milky Way
• The rapid formation a large rotating disk galaxy three billion years after the Big Bang
• Rapid formation of exponential disks and bulges at high redshift from the dynamical evolution of clump cluster and chain galaxies
• Bulge Formation by the Coalescence of Giant Clumps in Primordial Disk Galaxies
• Evidence for a clumpy, rotating gas disk in a submillimeter galaxy at z=4
• Clumpy Galaxies in GOODS and GEMS: Massive Analogs of Local Dwarf Irregulars
• A Survey of Galaxy Kinematics to z ~ 1 in the TKRS/GOODS-N Field. I. Rotation and Dispersion Properties
• Unstable disks at high redshift: Evidence for smooth accretion in galaxy formation
• Hubble Space Telescope H-alpha imaging of star-forming galaxies at z = 1-1.5: evolution in the size and luminosity of giant HII regions
• Halo Star Streams in the Solar Neighborhood
• Shocked Superwinds from the z~2 Clumpy Star-forming Galaxy, ZC406690
• Nuclear Black Hole Formation in Clumpy Galaxies at High Redshift
• Keck spectroscopy of globular clusters in the spiral galaxy NGC 2683
• Kinematic imprint of clumpy disk formation on halo objects

Cited by in corpus (6)

• Non-linear violent disc instability with high Toomre's Q in high-redshift clumpy disc galaxies
• Properties of thick discs formed in clumpy galaxies
• Spiral-arm instability - II: magnetic destabilisation
• The SLUGGS survey: chromo-dynamical modelling of the lenticular galaxy NGC 1023
• Chromodynamical Analysis of Lenticular Galaxies using Globular Clusters and Planetary Nebulae
• Kinematic imprint of clumpy disk formation on halo objects