J/ApJ/678/865 LONEOS-I RR Lyrae stars (Miceli+, 2008)
Evidence for distinct components of the galactic stellar halo from 838 RR Lyrae
stars discovered in the LONEOS-I survey.
Miceli A., Rest A., Stubbs C.W., Hawley S.L., Cook K.H., Magnier E.A.,
Krisciunas K., Bowell E., Koehn B.
<Astrophys. J., 678, 865-887 (2008)>
=2008ApJ...678..865M 2008ApJ...678..865M
ADC_Keywords: Stars, halo ; Stars, variable ; Photometry
Keywords: galaxies: halos - galaxies: individual (Milky Way) -
galaxies: structure
Abstract:
We present 838 ab-type RR Lyrae stars from the Lowell Observatory Near
Earth Objects Survey Phase I (LONEOS-I). These objects cover 1430deg2
and span distances ranging from 3 to 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 (ρOoI∼R-2.26±0.07 and
ρOoII∼R-2.88±0.11). This suggests that the stellar halo was
formed by at least two distinct accretion processes and supports
dual-halo models.
Description:
The LONEOS-I photometric variability database discussed in this paper
consists of photometric data obtained between 1998 and 2000. Situated
on the Anderson Mesa outside Flagstaff, Arizona, LONEOS is carried out
with a 0.6m Schmidt telescope. It covers a large fraction of the sky,
much of it imaged in multiple epochs (see Fig. 1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 42 838 Properties of 838 LONEOS-I RR Lyrae sample
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See also:
J/AJ/132/714 : QUEST RR Lyrae survey. II. Halo overdensities (Vivas+, 2006)
J/AJ/132/1202 : RR Lyrae in Northern Sky Variability Survey (Kinemuchi+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 21 F10.6 deg DEdeg Declination in decimal degrees (J2000)
23- 27 F5.2 mag <Vmag> Mean LONEOS V band magnitude (1)
29- 36 F8.6 d Per Period
38- 42 F5.3 mag Amp Amplitude (2)
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Note (1): Tied to the VSDSS system (VSDSS = r + 0.44(g-r) - 0.02)
Note (2): Measured from minimum to maximum brightness as defined by
the RR Lyrae template that best fit the lightcurve.
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Nomenclature note: objects are designed by
<[MRS2008] DDD.dddddd+DD.ddddddd> in Simbad.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Sep-2010