Skip to main content Accessibility help
×
Home
Hostname: page-component-59b7f5684b-b2xwp Total loading time: 0.276 Render date: 2022-09-27T04:46:56.982Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "useRatesEcommerce": false, "displayNetworkTab": true, "displayNetworkMapGraph": false, "useSa": true } hasContentIssue true

The dual nature of the Milky Way stellar halo

Published online by Cambridge University Press:  12 August 2011

Anna Curir
Affiliation:
INAF-Astronomical Observatory of Torino, strada Osservatorio 20, 10025 Pino Torinese (Torino)Italy email: curir@oato.inaf.it
Giuseppe Murante
Affiliation:
INAF-Astronomical Observatory of Torino, strada Osservatorio 20, 10025 Pino Torinese (Torino)Italy email: curir@oato.inaf.it
Eva Poglio
Affiliation:
Dept. of Physics, Turin University, Italy email: epoglio@studenti.ph.unito.it
Álvaro Villalobos
Affiliation:
INAF - Astronomical Observatory of Trieste, via Tiepolo 11, Trieste, Italy email: villalobos@oats.inaf.it
Rights & Permissions[Opens in a new window]

Abstract

HTML view is not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The theory of the Milky Way formation, in the framework of the ΛCDM model, predicts galactic stellar halos to be built from multiple accretion events starting from the first structure to collapse in the Universe.

Evidences in the past few decades have indicated that the Galactic halo consists of two overlapping structural components, an inner and an outer halo. We provide a set of numerical N-body simulations aimed to study the formation of the outer Milky Way (MW) stellar halo through accretion events between a (bulgeless) MW-like system and a satellite galaxy. After these minor mergers take place, in several orbital configurations, we analyze the signal left by satellite stars in the rotation velocity distribution. The aim is to explore the orbital conditions of the mergers where a signal of retrograde rotation in the outer part of the halo can be obtained, in order to give a possible explanation of the observed rotational properties of the MW stellar halo.

Our results show that the dynamical friction has a fundamental role in assembling the final velocity distributions originated by different orbits and that retrograde satellites moving on low inclination orbits deposit more stars in the outer halo regions and therefore can produce the counter-rotating behavior observed in the outer MW halo.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2011

References

Carollo, D., Beers, T. C., Sun Lee, Y., Chiba, M. E.Norris, J. E., Wilhelm, R., Sivarani, T., Marsteller, B., Munn, J. A., Bailer-Jones, C. A. L., Re Fiorentin, P. & York, D. G. 2007, Nature, 450, 1020CrossRefGoogle Scholar
Murante, G., Poglio, E., Curir, A. & Villalobos, A. 2010, ApJ (Letters), 716, L115CrossRefGoogle Scholar
Chandrasekar, S. 1943, ApJ, 97, 255CrossRefGoogle Scholar
Binney and Tremaine 1987, in: Galactic Dynamics (Princeton, NJ: Princeton University Press), p. 427Google Scholar
Navarro, J. F., Frenk, C. S. & White, S. D. M. 1997, ApJ, 190, 493CrossRefGoogle Scholar
Hernquist, L. 1990, ApJ, 356, 359CrossRefGoogle Scholar
Springel, V. 2005, ApJ, 364, 1105Google Scholar
Read, J. I., Lake, G., Agertz, O. & Debattista, V. P. 2008, MNRAS 389, 1041CrossRefGoogle Scholar
Bullock, J., Dekel, A., Kolatt, T., Kravtsov, A. V., Klypin, A. & Porciani, C. and Primack, J. 2001, ApJ, 555, 240CrossRefGoogle Scholar
Sales, L. V., Helmi, A., Starkenburg, E., MorrisonH., L. H., L., Engle, E., Harding, P., Mateo, M., OlszewskiE., W. E., W. & Sivarani, T. 2008, MNRAS 389, 1391CrossRefGoogle Scholar
Brunino, R., Trujillo, I., Pearce, F. R. & Thomas, P. A. 2007, MNRAS 375, 184CrossRefGoogle Scholar
You have Access

Save article to Kindle

To save this article to your Kindle, first ensure coreplatform@cambridge.org 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.

The dual nature of the Milky Way stellar halo
Available formats
×

Save article to Dropbox

To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.

The dual nature of the Milky Way stellar halo
Available formats
×

Save article to Google Drive

To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.

The dual nature of the Milky Way stellar halo
Available formats
×
×

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *