THE EPOCH OF DISK SETTLING: z {approx} 1 TO NOW

Journal Article · Sat Oct 20 00:00:00 EDT 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/758/2/106· OSTI ID:22086517

Kassin, Susan A; Gardner, Jonathan P ^[1]; Weiner, Benjamin J; Willmer, C N. A. ^[2]; Faber, S M; Guhathakurta, Puragra; Koo, David C ^[3]; Coil, Alison L ^[4]; Cooper, Michael C ^[5]; Devriendt, Julien ^[6]; Dutton, Aaron A ^[7]; Metevier, A J ^[8]; Noeske, Kai G ^[9]

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1. Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)
2. Steward Observatory, University of Arizona, Tucson, AZ (United States)
3. UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States)
4. Department of Physics, University of California, Santa Barbara, CA 93106 (United States)
5. Center for Galaxy Evolution, Department of Physics and Astronomy, University of California, Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697 (United States)
6. Department of Physics, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)
7. Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)
8. Department of Physics and Astronomy, Sonoma State University, 1801 East Cotati Avenue, Rohnert Park, CA 94928 (United States)
9. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

We present evidence from a sample of 544 galaxies from the DEEP2 Survey for evolution of the internal kinematics of blue galaxies with stellar masses ranging 8.0 < log M {sub *}(M {sub Sun }) < 10.7 over 0.2 < z < 1.2. DEEP2 provides galaxy spectra and Hubble imaging from which we measure emission-line kinematics and galaxy inclinations, respectively. Our large sample allows us to overcome scatter intrinsic to galaxy properties in order to examine trends in kinematics. We find that at a fixed stellar mass, galaxies systematically decrease in disordered motions and increase in rotation velocity and potential well depth with time. Massive galaxies are the most well ordered at all times examined, with higher rotation velocities and less disordered motions than less massive galaxies. We quantify disordered motions with an integrated gas velocity dispersion corrected for beam smearing ({sigma} {sub g}). It is unlike the typical pressure-supported velocity dispersion measured for early type galaxies and galaxy bulges. Because both seeing and the width of our spectral slits comprise a significant fraction of the galaxy sizes, {sigma} {sub g} integrates over velocity gradients on large scales which can correspond to non-ordered gas kinematics. We compile measurements of galaxy kinematics from the literature over 1.2 < z < 3.8 and do not find any trends with redshift, likely for the most part, because these data sets are biased toward the most highly star-forming systems. In summary, over the last {approx}8 billion years since z = 1.2, blue galaxies evolve from disordered to ordered systems as they settle to become the rotation-dominated disk galaxies observed in the universe today, with the most massive galaxies being the most evolved at any time.

• OSTI ID: 22086517
• Journal Information: Astrophysical Journal, Vol. 758, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTRONOMY
ASTROPHYSICS
ENERGY SPECTRA
GALACTIC EVOLUTION
GALAXIES
INCLINATION
MASS
PHOTON EMISSION
POTENTIALS
RED SHIFT
ROTATION
STARS
UNIVERSE
VELOCITY