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

Abstract

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{sup 2} and span distances ranging from 3-30kpc 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 ({rho}{sub OoI} {approx} R{sup -2.26{+-}0.07} and {rho}{sub OoII} {approx} R{sup -2.88{+-}0.11}). This suggests that the stellar halo was formed by at least two distinct accretion processes and supports dual-halo models.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
940509
Report Number(s):
UCRL-JRNL-228444
Journal ID: ISSN 0004-637X; ASJOAB; TRN: US200824%%72
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal, vol. 678, no. 2, May 1, 2008, pp. 865-887; Journal Volume: 678; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS; DISTRIBUTION; SPATIAL DISTRIBUTION; STARS

Citation Formats

Miceli, A, Rest, A, Stubbs, C W, Hawley, S L, Cook, K H, Magnier, E A, Krisciunas, K, Bowell, E, and Koehn, B. Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey. United States: N. p., 2007. Web.
Miceli, A, Rest, A, Stubbs, C W, Hawley, S L, Cook, K H, Magnier, E A, Krisciunas, K, Bowell, E, & Koehn, B. Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey. United States.
Miceli, A, Rest, A, Stubbs, C W, Hawley, S L, Cook, K H, Magnier, E A, Krisciunas, K, Bowell, E, and Koehn, B. Fri . "Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey". United States. doi:. https://www.osti.gov/servlets/purl/940509.
@article{osti_940509,
title = {Evidence for Distinct Components of the Galactic Stellar Halo from 838 RR Lyrae Stars Discovered in the LONEOS-I Survey},
author = {Miceli, A and Rest, A and Stubbs, C W and Hawley, S L and Cook, K H and Magnier, E A and Krisciunas, K and Bowell, E and Koehn, B},
abstractNote = {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{sup 2} and span distances ranging from 3-30kpc 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 ({rho}{sub OoI} {approx} R{sup -2.26{+-}0.07} and {rho}{sub OoII} {approx} R{sup -2.88{+-}0.11}). This suggests that the stellar halo was formed by at least two distinct accretion processes and supports dual-halo models.},
doi = {},
journal = {Astrophysical Journal, vol. 678, no. 2, May 1, 2008, pp. 865-887},
number = 2,
volume = 678,
place = {United States},
year = {Fri Feb 23 00:00:00 EST 2007},
month = {Fri Feb 23 00:00:00 EST 2007}
}