On the Keplerian Rotation Curves of Galaxies} %
Abstract
We propose a criterion for examining whether or not the uncertainty of the outer rotation curves is sufficiently small to distinguish a Keplerian rotation curve from flat ones. We have applied this criterion to both Keplerian and nonKeplerian rotation curves so far obtained, and investigated their relative fraction. We also studied the minimum extent of the dark halos indicated by nonKeplerian rotation curves using the criterion. We have found that one cannot rule out the possibility that a significant fraction of rotation curves become Keplerian within 10times the disk scale length. If the Keplerian rotation curves so far observed trace the mass truncation, several galaxies may have rather small halos, the extent of which is not larger than twice that of the optical disk.} %
 Publication:

Publications of the Astronomical Society of Japan
 Pub Date:
 October 1997
 DOI:
 10.1093/pasj/49.5.539
 arXiv:
 arXiv:astroph/9709217
 Bibcode:
 1997PASJ...49..539H
 Keywords:

 DARK MATTER;
 GALAXIES: SPIRAL;
 ROTATION;
 Astrophysics
 EPrint:
 Latex, 6 pages and 3 figures, to appear in PASJ Vol.49 No.5