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Date and Time of the Query: 2019-05-24 T10:02:57 PDT
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For refcode 1991AJ....101..456P:
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Copyright by American Astronomical Society. Reproduced by permission
1991AJ....101..456P H I STUDIES OF THE SCULPTOR GROUP GALAXIES. V. NGC 253 DANIEL PUCHE Very Large Array, National Radio Astronomy Observatory, P. O. Box 0, Socorro, New Mexico 87801 CLAUDE CARIGNAN Departement de Physique and Observatoire du Mont Megantic, Universite de Montreal, C. P. 6128, Succ. "A", Montreal, Quebec, H3C 317 Canada JACQUELINE H. VAN GORKOM Department of Astronomy, Columbia University, Box 52, Pupin Hall, 538 West 120th Street, New York, New York 10027 Received 18 June 1990; revised 1 October 1990 ABSTRACT A study of the H I properties and mass distribution of the Sculptor group galaxy NGC 253, from VLA observations, is presented. The detected H I disk is fairly small with a diameter 0.8D_HO_. The rotation curve, derived from the velocity field using a full tilted ring model, is still rising at the last observed point. The maximum observed rotation velocity is V_rot_~ 224 km s^1^ at a radius of ~8.5 kpc. From this analysis, a systematic velocity of 245 km s^1^, a mean inclination i~72^deg^, and a mean position angle P. A.~229^deg^ are derived. The study of the mass distribution shows that a two-component (luminous and dark) mass model is needed to explain the observed rotation curve over the whole radius range. An exponential disk and an isothermal sphere are fitted to the rotation curve. The maximum (M/LB)_*_ found is highly dependent on the value of the internal absorption used. It varies from (M/LB)_*_~ 4 to (M/LB)_*_~ 13 if different absorption corrections are applied to the luminosity profile. The halo parameters are a core radius r_c_~27 kpc and a central density P_0_~ 0.015 M_sun_pc^3^.
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