Details

Autor(en) / Beteiligte

• Miceli, Antonino
• Rest, Armin
• Stubbs, Christopher W
• Hawley, Suzanne L
• Cook, Kem H
• Magnier, Eugene A
• Krisciunas, Kevin
• Bowell, Edward
• Koehn, Bruce

Titel

Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey

Ist Teil von

• The Astrophysical journal, 2008-05, Vol.678 (2), p.865-887

Ort / Verlag

Chicago, IL: IOP Publishing

Erscheinungsjahr

2008

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• We present 838 ab-type RR Lyrae stars from the Lowell Observatory Near Earth Objects Survey Phase I (LONEOS-I). These objects cover 1430 deg super(2) and span distances ranging from 3 to 30 kpc from the Galactic center. Object selection is based on phased, photometric data with 28-50 epochs. We use this large sample to explore the bulk properties of the stellar halo, including the spatial distribution. The period-amplitude distribution of this sample shows that the majority of these RR Lyrae stars resemble Oosterhoff type I, but there is a significant fraction (26%) which have longer periods and appear to be Oosterhoff type II. We find that the radial distributions of these two populations have significantly different profiles ([image] and [image]). This suggests that the stellar halo was formed by at least two distinct accretion processes and supports dual-halo models.