Resolved gas kinematics in a sample of low-redshift high star-formation rate galaxies

Abstract

We have used integral field spectroscopy of a sample of six nearby (z~0.01-0.04) high star-formation rate (SFR~10-40 solar masses per year) galaxies to investigate the relationship between local velocity dispersion and star formation rate on sub-galactic scales. The low redshift mitigates, to some extent, the effect of beam smearing which artificially inflates the measured dispersion as it combines regions with different line-of-sight velocities into a single spatial pixel. We compare the parametric maps of the velocity dispersion with the Halpha flux (a proxy for local star-formation rate), and the velocity gradient (a proxy for the local effect of beam smearing). We find, even for these very nearby galaxies, the Halpha velocity dispersion correlates more strongly with velocity gradient than with Halpha flux - implying that beam smearing is still having a significant effect on the velocity dispersion measurements. We obtain a first-order non parametric correction for the unweighted and flux weighted mean velocity dispersion by fitting a 2D linear regression model to the spaxel-by-spaxel data where the velocity gradient and the Halpha flux are the independent variables and the velocity dispersion is the dependent variable; and then extrapolating to zero velocity gradient. The corrected velocity dispersions are a factor of ~1.3-4.5 and ~1.3-2.7 lower than the uncorrected flux-weighted and unweighted mean line-of-sight velocity dispersion values, respectively. These corrections are larger than has been previously cited using disc models of the velocity and velocity dispersion field to correct for beam smearing. The corrected flux-weighted velocity dispersion values are sigma_m~20-50 km/s.

arXiv comment12 pages, 4 figures

References in corpus (37)

• Galactic Stellar and Substellar Initial Mass Function
• On the variation of the Initial Mass Function
• The Seventh Data Release of the Sloan Digital Sky Survey
• The Global Schmidt Law in Star Forming Galaxies
• Cosmic Star Formation History
• The physical properties of star forming galaxies in the low redshift universe
• Stellar Masses and Star Formation Histories for 10^5 Galaxies from the Sloan Digital Sky Survey
• The SINS survey: SINFONI Integral Field Spectroscopy of z ~ 2 Star-forming Galaxies
• The SINS survey of z~2 galaxy kinematics: properties of the giant star forming clumps
• The KMOS^3D Survey: design, first results, and the evolution of galaxy kinematics from 0.7<z<2.7
• The rapid formation a large rotating disk galaxy three billion years after the Big Bang
• Star formation rate indicators in the Sloan Digital Sky Survey
• The Kiloparsec-Scale Kinematics of High-Redshift Star-Forming Galaxies
• The SINS survey: modeling the dynamics of z~2 galaxies and the high-z Tully-Fisher relation
• The Wide Field Spectrograph (WiFeS): Performance and Data Reduction
• ISM properties in hydrodynamic galaxy simulations: Turbulence cascades, cloud formation, role of gravity and feedback
• Clumpy Galaxies in GOODS and GEMS: Massive Analogs of Local Dwarf Irregulars
• Evidence for strong dynamical evolution in disk galaxies through the last 11 Gyr. GHASP VIII: A local reference sample of rotating disk galaxies for high redshift studies
• Resolved Spectroscopy of Gravitationally-Lensed Galaxies: Recovering Coherent Velocity Fields in Sub-Luminous z~2-3 Galaxies
• GHASP : An Halpha kinematic survey of spiral and irregular galaxies - VI. New Halpha data cubes for 108 galaxies
• PyWiFeS: A Rapid Data Reduction Pipeline for the Wide Field Spectrograph (WiFeS)
• DYNAMO I: A Sample of Ha-Luminous Galaxies with Resolved Kinematics
• Integral Field Spectroscopy of High-Redshift Star Forming Galaxies with Laser Guided Adaptive Optics: Evidence for Dispersion-Dominated Kinematics
• How well can we Measure the Intrinsic Velocity Dispersion of Distant Disk Galaxies?
• High star formation rates as the origin of turbulence in early and modern disk galaxies
• Dynamics of Galactic Disks and Mergers at z~1.6: Spatially Resolved Spectroscopy with Keck Laser Guide Star Adaptive Optics
• The SINS/zC-SINF Survey of z~2 Galaxy Kinematics: The Nature of Dispersion Dominated Galaxies
• Accretion-Driven Turbulence and the Transition to Global Instability in Young Galaxy Disks
• GHASP : An Halpha kinematic survey of 203 spiral and irregular galaxies - VII. Revisiting the analysis of Halpha data cubes for 97 galaxies
• The WiggleZ Dark Energy Survey: High Resolution Kinematics of Luminous Star-Forming Galaxies
• IMAGES I. Strong evolution of galaxy kinematics since z=1
• MASSIV: Mass Assemby Survey with SINFONI in VVDS. I. Survey description and global properties of the 0.9 < z < 1.8 galaxy sample
• MASSIV: Mass Assembly Survey with SINFONI in VVDS. IV. Fundamental relations of star-forming galaxies at 1<z< 1.6
• The structure of gravitationally unstable gas-rich disk galaxies
• 2D Kinematics and Physical Properties of z~3 Star-Forming Galaxies
• A dynamical mass estimator for high z galaxies based on spectroastrometry
• Spatially Resolved Spectroscopy of Starburst and Post-Starburst Galaxies in The Rich z~0.55 Cluster CL0016+16

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