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The Structure of Rapidly Rotating Late-Type Spiral Galaxies. I. Photometry, H I, and Optical Kinematics
We present I-band photometry, long-slit optical spectroscopy, and newaperture synthesis H I observations for eight late-type spiral galaxieswith rotation velocities in the range 243 kms-1<~Vrot<~308 km s-1. The samplewill be used to study the structure and angular momentum of disks at thehigh-mass end of the spiral galaxy population; here we discuss the basicproperties of these ``fast rotators'' and derive hybrid optical/H Irotation curves for each. Despite the presence of H I warps and low-masscompanions in many systems, their kinematics are regular and there isexcellent agreement between optical and H I tracers near the opticalradius ropt. At high inclinations at which projection effectsare negligible, the sample galaxies exhibit flat, featureless rotationcurves out to their last measured points at1.7ropt-3.5ropt. The intermediate-inclinationsystems are also consistent with a constant rotation amplitude forr>~0.5ropt. We therefore find no evidence for decliningrotation curves at the high-mass end of the late-type spiral galaxypopulation. Combining our data with the compilation of spiral galaxieswith reliable outer H I kinematics from the work of Casertano and vanGorkom, we find no convincing trends between logarithmic outer rotationcurve slopes and rotation amplitudes or surface brightnesses forgalaxies with Vrot>~220 km s-1. Correlationsbetween these slopes and morphological types or disk scale lengths arealso marginal in this regime.
| Kinematical observations of ordinary spiral galaxies - A bibliographical compilation
Data extracted from 280 papers reporting observations of the kinematicsof 245 nonbarred spiral galaxies are presented. Information is providedon the type of observations (instruments, spectral lines used, etc.) andthe derived geometrical and kinematical parameters of the galaxies(major axis position angle, inclination, heliocentric systemic velocity,maximum extension of the kinematical measurements, etc.). In addition,whenever possible, a 'mean' rotation curve has been considered, fromwhich the maximum rotational velocity of the galaxy and a parameterdescribing the essential shape of the rotation curve within r25 havebeen derived. Histograms illustrating the distribution of morphologicaltypes, inclinations, extensions of the kinematical measurements, andmaximum rotational velocities account for the statistical properties ofthis sample of spiral galaxies.
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