J/ApJ/780/59 The Araucaria project: eclipsing binaries in SMC (Graczyk+, 2014)
The Araucaria project. The distance to the Small Magellanic Cloud from late-type
eclipsing binaries.
Graczyk D., Pietrzynski G., Thompson I.B., Gieren W., Pilecki B.,
Konorski P., Udalski A., Soszynski I., Villanova S., Gorski M.,
Suchomska K., Karczmarek P., Kudritzki R.-P., Bresolin F., Gallenne A.
<Astrophys. J., 780, 59 (2014)>
=2014ApJ...780...59G 2014ApJ...780...59G
ADC_Keywords: Magellanic Clouds ; Binaries, eclipsing ; Stars, late-type ;
Photometry ; Radial velocities
Keywords: binaries: eclipsing - galaxies: individual: SMC - stars: late-type
Abstract:
We present a distance determination to the Small Magellanic Cloud
(SMC) based on an analysis of four detached, long-period, late-type
eclipsing binaries discovered by the Optical Gravitational Lensing
Experiment (OGLE) survey. The components of the binaries show
negligible intrinsic variability. A consistent set of stellar
parameters was derived with low statistical and systematic
uncertainty. The absolute dimensions of the stars are calculated with
a precision of better than 3%. The surface brightness-infrared color
relation was used to derive the distance to each binary. The four
systems clump around a distance modulus of (m - M) = 18.99 with a
dispersion of only 0.05 mag. Combining these results with the distance
published by Graczyk et al. for the eclipsing binary OGLE SMC113.3
4007, we obtain a mean distance modulus to the SMC of 18.965±0.025
(stat.)±0.048 (syst.) mag. This corresponds to a distance of
62.1±1.9 kpc, where the error includes both uncertainties. Taking
into account other recent published determinations of the SMC distance
we calculated the distance modulus difference between the SMC and the
Large Magellanic Cloud equal to 0.458±0.068 mag. Finally, we
advocate µSMC= 18.95±0.07 as a new "canonical" value of the
distance modulus to this galaxy.
Description:
With the exception of SMC130.5 4296, our targets were discovered by
Udalski et al. 1998 (cat. J/AcA/48/563) and confirmed to be eclipsing
binaries by Wyrzykowski et al. 2004 (cat. J/AcA/54/1).
Optical photometry in the Johnson-Cousins filters was obtained with
the Warsaw 1.3m telescope at Las Campanas Observatory in the course of
the second, third and fourth phase of the Optical Gravitational
Lensing Experiment (OGLE) project (Udalski et al.,
1997AcA....47..319U 1997AcA....47..319U; Udalski, 2003AcA....53..291U 2003AcA....53..291U; Soszynski et al.
2012, cat. J/AcA/62/219). We secured 5314 I-band measurements and 391
V-band measurements for five eclipsing binaries.
Near-infrared photometry was collected with the ESO NTT telescope on
La Silla, equipped with the SOFI camera (PI: Pietrzynski). The setup
of the instrument, reduction, and calibration of the data onto the
UKIRT system were essentially the same as described in Pietrzynski et
al. (2009ApJ...697..862P 2009ApJ...697..862P). We transformed our photometry onto the
Johnson system.
High resolution echelle spectra were collected with the Clay 6.5m
telescope at Las Campanas, equipped with the MIKE spectrograph and
with the 3.6m telescope in La Silla, equipped with the HARPS
spectrograph. We used a 5*0.7arcsec slit with MIKE giving a resolution
of about 40000. In the case of HARPS, we used the EGGS mode giving a
resolution of about R∼80000. The typical signal-to-noise ratio (S/N)
at ∼5300Å was about 20 and 6 for the MIKE-Red part and HARPS
spectra, respectively, and about 12 at ∼4700Å for the MIKE-Blue
part spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 77 4 The target stars
table2.dat 32 5720 The photometry of target systems
table3.dat 55 147 The radial velocities measurements
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See also:
II/322 : OGLE-III. Magellanic Clouds stellar proper motions (Poleski+, 2012)
J/AcA/62/219 : OGLE: Gaia South Ecliptic Pole Field (Soszynski+, 2012)
J/AJ/138/1661 : The Araucaria Project: RR Lyrae in SMC (Szewczyk+, 2009)
J/AcA/54/1 : OGLE II SMC eclipsing binaries (Wyrzykowski+, 2004)
J/AcA/48/563 : BVI photometry of OGLE SMC eclipsing binaries (Udalski+, 1998)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Field OGLE-SMC field (SMCNNN.N)
10- 14 I5 --- OGLE Identifier of target eclipsing binary system
16- 21 A6 --- Name Shortened name of target eclipsing binary system
(column added at CDS)
23- 24 I2 h RAh Hour of Right Ascension (J2000)
26- 27 I2 min RAm Minute of Right Ascension (J2000)
29- 33 F5.2 s RAs Second of Right Ascension (J2000)
35 A1 --- DE- Sign of the Declination (J2000)
36- 37 I2 deg DEd Degree of Declination (J2000)
39- 40 I2 arcmin DEm Arcminute of Declination (J2000)
42- 45 F4.1 arcsec DEs Arcsecond of Declination (J2000)
47- 52 F6.3 mag Vmag The V-band magnitude
54- 58 F5.3 mag V-I The (V-I) color index
60- 64 F5.3 mag V-K The (V-K) color index
66- 70 F5.3 mag J-K The (J-K) color index
72- 77 F6.2 d Per Orbital period
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Shortened name of target eclipsing binary system
8 A1 --- Band [VIK] Photometric band of observation
10- 19 F10.5 d HJD Heliocentric Julian Date (HJD-2450000)
21- 26 F6.3 mag mag Observed magnitude in Band
28- 32 F5.3 mag e_mag Error in mag
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Shortened name of target eclipsing binary system
8- 17 F10.5 d HJD Heliocentric Julian Date (HJD-2450000)
19- 25 F7.3 km/s RV1 Radial velocity of a primary component
27- 31 F5.3 km/s e_RV1 Formal error in RV1
33- 39 F7.3 km/s RV2 Radial velocity of a secondary component
41- 45 F5.3 km/s e_RV2 Formal error in RV2
47- 55 A9 --- Inst Identification of the spectrograph used (HARPS,
MIKE-Blue, or MIKE-Red) (1)
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Note (1): The instruments used are :
HARPS = HARPS spectrograph (on the 3.6m telescope in La Silla);
MIKE-Blue = MIKE spectrograph on the Clay 6.5m telescope at Las Campanas
(S/N at ∼4700Å was about 12);
MIKE-Red = MIKE spectrograph on the Clay 6.5m telescope at Las Campanas
(S/N at ∼5300Å was about 20).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 28-Jan-2015