J/ApJ/721/L28 Red clump stars in Galactic Bulge from OGLE-III (Nataf+, 2010)
The split red clump of the Galactic Bulge from OGLE-III.
Nataf D.M., Udalski A., Gould A., Fouque P., Stanek K.Z.
<Astrophys. J., 721, L28-L32 (2010)>
=2010ApJ...721L..28N 2010ApJ...721L..28N
ADC_Keywords: Milky Way ; Stars, horizontal branch ; Photometry, VRI
Keywords: Galaxy: bulge - Galaxy: structure - stars: horizontal-branch
Abstract:
The red clump (RC) is found to be split into two components along
several sightlines toward the Galactic bulge. This split is detected
with high significance toward the areas (-3.5<l<1,b←5) and
(l,b)=(0,+5.2), i.e., along the bulge minor axis and at least 5 deg
off the plane. The fainter (hereafter "main") component is the one
that more closely follows the distance-longitude relation of the bulge
RC. The main component is ∼0.5mag fainter than the secondary component
and with an overall approximately equal population. For sightlines
further from the plane, the difference in brightness increases, and
more stars are found in the secondary component than in the main
component. The two components have very nearly equal (V-I) color.
Description:
OGLE-III (Udalski et al. 2003AcA....53..291U 2003AcA....53..291U, 2008AcA....58...69U 2008AcA....58...69U,
Szymanski et al. 2011AcA....61...83S 2011AcA....61...83S) observations were obtained from
the 1.3m Warsaw Telescope, located at the Las Campanas Observatory in
Chile. We use observations from a mosaic of 267 fields directed toward
the Galactic bulge, which are almost entirely within the range
-10<l<10 and 2<|b|<7 (see Figure 1). An investigation of the red clump
(RC) across the entire OGLE-III Galactic bulge data set is in progress
(D. M. Nataf et al. 2012arXiv1208.1263N 2012arXiv1208.1263N).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 5085 Red clump (RC) stars which have been tabulated
from 21 high-confidence sightlines
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See also:
J/AcA/52/217 : OGLE II. VI photometry of Galactic Bulge (Udalski+, 2002)
ftp://ftp.astrouw.edu.pl/ogle/ogle3/maps/blg/ : OGLE-III Photometric Maps of
the Galactic bulge
http://ogle.astrouw.edu.pl/~ogle/ : OGLE home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 --- Field [127.4/357.8] Subfield (FFF.F)
7- 12 I6 --- Seq OGLE-III sequence number (NNNNNN)
14- 22 A9 --- Status Status (Main or Secondary) (1)
24- 25 I2 h RAh [17/18] Hour of right ascension (J2000)
27- 28 I2 min RAm Minute of right ascension (J2000)
30- 34 F5.2 s RAs Second of right ascension (J2000)
36 A1 --- DE- [-] Sign of declination (J2000)
37- 38 I2 deg DEd [25/35] Degree of declination (J2000)
40- 41 I2 arcmin DEm Arcminute of declination (J2000)
43- 46 F4.1 arcsec DEs Arcsecond of declination (J2000)
48- 52 F5.3 mag V-I [1.27/2.27] V-I color index (1)
54- 59 F6.3 mag Imag [14.50/16.19] I-band magnitude (1)
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Note (1): Selected stars had a (V-I) within 0.15mag that of the fit, and
were assigned "Main" (Faint) or "Secondary" (Bright) status if their
I-band brightness was within 0.15mag of the fit value. V-I and I might
be off by ∼0.02mag in some cases as it is based on OGLE-III photometry
before final release.
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Nomenclature Notes:
Stars are named in Simbad, from the field number
(FFF.F) and the sequence number (NNNNNN).
Acknowledgements:
David M. Nataf <nataf(at)astronomy.ohio-state.edu>
(End) Emmanuelle Perret [CDS] 10-Jul-2012