March 23 (Reuters) - The S&P 500 and the Dow edged lower at open on Tuesday as energy and travel stocks slipped, while investors awaited remarks from Fed Chair Jerome Powell and Treasury Secretary Janet Yellen for clues on the health of the economy. The Dow Jones Industrial Average fell 39.7 points, or 0.12%, at the open to 32691.5. The S&P 500 fell 3.0 points, or 0.08%, at the open to 3937.6, while the Nasdaq Composite rose 3.9 points, or 0.03%, to 13381.435 at the opening bell. (Reporting by Devik Jain in Bengaluru; Editing by Anil D’Silva)