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The Kinematics of the Planetary Nebula Population in M94

N. G. Douglas·J. Gerssen·K. Kuijken·M. R. Merrifield
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Abstract

The planetary nebula populations of relatively nearby galaxies can be easily observed and provide both a distance estimate and a tool with which dynamical information can be obtained. Usually the requisite radial velocities are obtained by multi-object spectroscopy once the planetary nebulae have been located by direct imaging. Here we report on a technique for measuring planetary nebula kinematics using the double-beam ISIS spectrograph at the William Herschel Telescope in a novel slitless mode, which enables the detection and radial velocity measurements to be combined into a single step. The results on our first target, the Sab galaxy NGC 4736, allow the velocity dispersion of the stellar population in a disk galaxy to be traced out to four scale lengths for the first time and are consistent with a simple isothermal sheet model.

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N. G. Douglas, J. Gerssen, K. Kuijken, M. R. Merrifield. 2000-03-20. The Kinematics of the Planetary Nebula Population in M94. https://arxiv.org/abs/astro-ph/0003281

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