The rotational velocity of a galaxy at a distance of 0.15 arcseconds from the centre is ~597 km/s. The galaxy is 20 Mpc away from us and the mass contained within 0.15 arcseconds from the center is 7.8 × 108 Mo. Verify (within small approximation) that this mass estimate is consistent with a Keplerian dynamics motion of the mass within the specified distance from the centre. NOTE: you can assume the mass provided comes from independent observations not related to dynamics considerations.

The rotational velocity of a galaxy at a distance of 0.15 arcseconds from the centre is ~597 km/s. The galaxy is 20 Mpc away from us and the mass contained within 0.15 arcseconds from the center is 7.8 × 108 Mo. Verify (within small approximation) that this mass estimate is consistent with a Keplerian dynamics motion of the mass within the specified distance from the centre. NOTE: you can assume the mass provided comes from independent observations not related to dynamics considerations.

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