We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
Published online by Cambridge University Press: 10 November 2010
Galactic bulges probably formed in starbursts such as those studied during this conference. We study the population contents and spatial structure of bulges to learn on the star formation history of these systems. From broadband optical CCD images we derive mean colours and colour gradients for a complete sample of ∼ 40 bulges of edge-on galaxies. After excluding objects with dust, the colours trace age and metallicity of the stellar populations. Metallicities inferred from the colours seldom reach solar values. This result is consistent with recent metallicity estimates for the Milky Way (MW) Bulge derived from spectroscopy of K giants. Colour profiles have negative slopes, i.e. colours become bluer outward. The derived gradients are similar to those observed in elliptical galaxies. Gradients of more luminous bulges are steeper than those of smaller bulges.
Introduction
Our notions on the stellar content of spiral bulges are largely derived from studies of a few nearby cases, notably our own MW Bulge. We know that the spectra of bulges often resemble more the strong-lined spectra of elliptical nuclei than those of metal-poor halo stars (Whitford 1978). It is also known that the MW Bulge, at Baade's window (BW) at least, contains stars of very high metallicity (Rich 1988).
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.
