ON SIZES, KINEMATICS, M/L GRADIENTS, AND LIGHT PROFILES OF MASSIVE COMPACT GALAXIES AT z {approx} 2
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
- Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States)
- Leiden University, Leiden Observatory, P.O. Box 9513, NL-2300 RA, Leiden (Netherlands)
- Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States)
- Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States)
We present a detailed analysis of the structure and resolved stellar populations of simulated merger remnants, and compare them to observations of compact quiescent galaxies at z {approx} 2. We find that major merging is a viable mechanism to produce systems of {approx}10{sup 11} M{sub sun} and {approx}1 kpc size, provided the gas fraction at the time of final coalescence is high ({approx}40%) and provided that the progenitors are compact star-forming galaxies, as expected at high redshift. Their integrated spectral energy distributions and velocity dispersions are in good agreement with the observations, and their position in the (v{sub maj}/{sigma}, {epsilon}) diagram traces the upper envelope of the distribution of lower redshift early-type galaxies. The simulated merger remnants show time- and sightline-dependent M/L ratio gradients that result from a superposition of radially dependent stellar age, stellar metallicity, and extinction. The median ratio of the effective radius in rest-frame V-band light to that in mass surface density is {approx}2 during the quiescent remnant phase. This is typically expressed by a negative color gradient (i.e., red core), which we expect to correlate with the integrated color of the system. Finally, the simulations differ from the observations in their surface brightness profile shape. The simulated remnants are typically best fit by high (n >> 4) Sersic indices, whereas observed quiescent galaxies at z {approx} 2 tend to be less cuspy ((n) {approx} 2.3). Limiting early star formation in the progenitors may be required to prevent the simulated merger remnants from having extended wings.
- OSTI ID:
- 21464589
- Journal Information:
- Astrophysical Journal, Vol. 722, Issue 2; Other Information: DOI: 10.1088/0004-637X/722/2/1666; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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