Deep Ccd Surface Photometry Of Nearby Spiral Galaxies

Author : Eric Miller
Publisher :
ISBN 13 :
Total Pages : 212 pages
Book Rating : 4.:/5 (864 download)

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Download or read book Deep R-band Surface Photometry of NGC891 written by Eric Miller and published by . This book was released on 1996 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how galaxies evolve is a challenge for astronomers, given the very long timescales for such evolution to occur. Fortunately, the structure of a galaxy encodes a fossil record of its evolution. In particular, by decomposing this structure into a number of independent components, we can compare the results to theoretical predictions and begin to trace the history of mass accretion and star formation that have shaped the stellar systems we see today. In this thesis, I present deep optical R-band surface photometry of the nearby edge-on spiral galaxy NGC891. This galaxy bears many similarities to the Milky Way, and thus exploring its structure can improve our understanding of our own Galaxy's evolution. Using a method developed by collaborators to carefully exposure-correct the image data and remove contributions of foreground stars, I am able to detect diffuse stellar light from NGC891 to a level 8 magnitudes (or 1500 times) fainter than the night sky background. Using one-dimensional surface brightness profiles extracted perpendicular to the galactic disk, I detect two vertically extended stellar disk components: a "thin disk" with scale height 0.6 kpc; and a "thick disk" with scale height of 1.7 kpc. The thin disk is considerably more extended than the corresponding component in the Milky Way, perhaps because of heating from the more massive molecular cloud layer in NGC891. The origin of the extended thick disk is not completely understood at this time and requires further two-dimensional modeling. Such modeling will also help constrain the presence of an extended stellar halo, which is not detected in this work.