Measuring Galaxy Velocity Dispersions with Hectospec

Abstract

We describe a robust technique based on the ULySS IDL code for measuring velocity dispersions of galaxies observed with the MMT's fiber-fed spectrograph, Hectospec. This procedure is applicable to all Hectospec spectra having a signal-to-noise >5 and weak emission lines. We estimate the internal error in the Hectospec velocity dispersion measurements by comparing duplicate measurements of 171 galaxies. For a sample of 984 galaxies with a median z=0.10, we compare velocity dispersions measured by Hectospec through a 1.5 arcsec diameter optical fiber with those measured by the Sloan Digital Sky Survey (SDSS) and Baryon Oscillation Spectral Survey (BOSS) through 3 arcsec and 2 arcsec diameter optical fibers, respectively. The systematic differences between the Hectospec and the SDSS/BOSS measurements are <7% for velocity dispersions between 100 and 300 km/s, the differences are no larger than the differences among the three BOSS velocity dispersion reductions. We analyze the scatter about the fundamental plane and find no significant redshift dependent systematics in our velocity dispersion measurements to z~0.6. This analysis also confirms our estimation of the measurement errors. In one hour in good conditions, we demonstrate that we achieve 30 km/s velocity dispersion errors for galaxies with an SDSS r fiber magnitude of 21.

8 figures

References in corpus (22)

• Parametric Recovery of Line-of-Sight Velocity Distributions from Absorption-Line Spectra of Galaxies via Penalized Likelihood
• MILES: A Medium resolution INT Library of Empirical Spectra
• The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
• The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the fundamental plane of elliptical and lenticular galaxies
• The First Data Release of the Sloan Digital Sky Survey
• An updated MILES stellar library and stellar population models
• Spectral Classification and Redshift Measurement for the SDSS-III Baryon Oscillation Spectroscopic Survey
• ULySS: A Full Spectrum Fitting Package
• Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph
• Evolutionary synthesis of galaxies at high spectral resolution with the code PEGASE-HR
• Stellar velocity dispersions and emission line properties of SDSS-III/BOSS galaxies
• Measuring the Ultimate Mass of Galaxy Clusters: Redshifts and Mass Profiles from the Hectospec Cluster Survey (HeCS)
• SDSSJ150634.27+013331.6: the second compact elliptical galaxy in the NGC5846 group
• The atmospheric parameters and spectral interpolator for the stars of MILES
• First Results On Shear-Selected Clusters From the Deep Lens Survey: Optical Imaging, Spectroscopy, and X-ray Followup
• The luminosity and stellar mass Fundamental Plane of early-type galaxies
• The Deep Lens Survey
• Spectrophotometry with Hectospec, the MMT's Fiber-Fed Spectrograph
• SHELS: Testing Weak Lensing Maps with Redshift Surveys
• The Faint End of the Luminosity Function and Low Surface Brightness Galaxies
• Mapping the Universe: The 2010 Russell Lecture
• Dust-Obscured Galaxies in the Local Universe

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• Separating Galaxies from the Cluster Dark Matter Halo in Abell 611
• The Stellar Mass Fundamental Plane and Compact Quiescent Galaxies at z < 0.6
• A Complete Spectroscopic Census of Abell 2029: A Tale of Three Histories
• The Coevolution of Massive Quiescent Galaxies and Their Dark Matter Halos over the Last 6 Billion Years
• The Velocity Dispersion Function for Quiescent Galaxies in Nine Strong-Lensing Clusters
• Velocity distribution of elliptical galaxies in the framework of Non-local Gravity model
• Estimating Statistical Uncertainties of Internal Kinematics of Galaxies and Star Clusters Derived Using Full Spectrum Fitting
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