THE PROPERTIES OF THE STAR-FORMING INTERSTELLAR MEDIUM AT z = 0.8-2.2 FROM HiZELS: STAR FORMATION AND CLUMP SCALING LAWS IN GAS-RICH, TURBULENT DISKS

Journal Article · Sat Dec 01 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/2/130· OSTI ID:22086210

Swinbank, A M; Smail, Ian; Theuns, T ^[1]; Sobral, D ^[2]; Best, P N ^[3]

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1. Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
2. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
3. SUPA, Institute for Astronomy, University of Edinburgh, Edinburgh EH19 3HJ (United Kingdom)

We present adaptive optics assisted integral field spectroscopy of nine H{alpha}-selected galaxies at z = 0.84-2.23 drawn from the HiZELS narrowband survey. Our observations map the kinematics of these star-forming galaxies on {approx}kpc scales. We demonstrate that within the interstellar medium of these galaxies, the velocity dispersion of the star-forming gas ({sigma}) follows a scaling relation {sigma}{proportional_to}{Sigma}{sup 1/n} {sub SFR} + constant (where {Sigma}{sub SFR} is the star formation surface density and the constant includes the stellar surface density). Assuming the disks are marginally stable (Toomre Q = 1), this follows from the Kennicutt-Schmidt relation ({Sigma}{sub SFR} = A{Sigma} {sup n} {sub gas}), and we derive best-fit parameters of n = 1.34 {+-} 0.15 and A = 3.4{sup +2.5} {sub -1.6} Multiplication-Sign 10{sup -4} M {sub Sun} yr{sup -1} kpc{sup -2}, consistent with the local relation, and implying cold molecular gas masses of M {sub gas} = 10{sup 9-10} M {sub Sun} and molecular gas fractions of M {sub gas}/(M {sub gas} + M {sub *}) = 0.3 {+-} 0.1, with a range of 10%-75%. We also identify 11 {approx}kpc-scale star-forming regions (clumps) within our sample and show that their sizes are comparable to the wavelength of the fastest growing mode. The luminosities and velocity dispersions of these clumps follow the same scaling relations as local H II regions, although their star formation densities are a factor {approx}15 {+-} 5 Multiplication-Sign higher than typically found locally. We discuss how the clump properties are related to the disk, and show that their high masses and luminosities are a consequence of the high disk surface density.

• OSTI ID: 22086210
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 760; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION SPECTROSCOPY
ASTRONOMY
ASTROPHYSICS
DENSITY
EMISSION SPECTROSCOPY
GALACTIC EVOLUTION
GALAXIES
LUMINOSITY
RED SHIFT
SCALING LAWS
STAR EVOLUTION
STARS
SURFACES