MEASURING SPIRAL ARM TORQUES - RESULTS FOR M100
Megjelenés dátuma: 1995
MTMT: 1115191
WoS ID: A1995RR92700015
Scopus ID: 0042777138
DOI: 10.1086/117590
Absztrakt:
Spiral arms, if they are massive, exert gravitational torques on stars
that transport angular momentum radially within galactic disks. These
torques depend not on the pattern speed or permanence of the arms but
only on the nonaxisymmetric mass distribution. Hence the torques can be
measured directly from photometry. We demonstrate this using gri CCD
data for M100 (NGC 4321). Since we find consistency among the three
bands, we believe that dust and young stars in the arms do not
seriously bias our results. if the present epoch is representative, the
time scale for redistribution of angular momentum in M100 is 5-10 Gyr.
(C) 1995 American Astronomical Society.