J/A+A/537/A116 Variables in Centaurus field F170 (Pietrukowicz+, 2012)
Variability and stellar populations with deep optical-IR images of the Milky Way
disc: matching VVV with VLT/VIMOS data.
Pietrukowicz P., Minniti D., Alonso-Garcia, J., Hempel M.
<Astron. Astrophys. 537, A116 (2012)>
=2012A&A...537A.116P 2012A&A...537A.116P
ADC_Keywords: Stars, variable ; Binaries, eclipsing ; Stars, nearby ; Photometry
Keywords: Hertzsprung-Russell and C-M diagrams - binaries: eclipsing -
Galaxy: structure - Galaxy: disk - stars: variables: delta Scuti
Abstract:
We have used deep V-band and JHKs-band observations to investigate
variability and stellar populations near the Galactic plane in
Centaurus, and compare the observations with the Galactic model of
Besancon. By applying image subtraction technique to a series of over
580 V-band frames taken with the ESO VLT/VIMOS instrument during two
contiguous nights in April 2005 we have detected 333 variables among
84,734 stars in the brightness range 12.7<V<26.0mag. Infrared
data collected in March 2010 with the new ESO VISTA telescope allowed
us to construct deep combined optical-IR colour-magnitude and
colour-colour diagrams. All detected variables but four transit
candidates are reported for the first time. The majority of the
variables are eclipsing/ellipsoidal binaries and delta Scuti-type
pulsators. The occurrence rate of eclipsing/ellipsoidal variables
reached ∼0.28% of all stars. This is very close to the highest
fraction of binary systems detected using ground-based data so far
(0.30%), but still about four times smaller than the average
occurrence rate recently obtained from the Kepler space mission after
44 days of operation. Comparison of the observed Ks vs. V-Ks diagram
with a diagram based on the Besancon model shows significant effects
of both distance and reddening in the investigated direction of the
sky. We demonstrate that the best model indicates presence of
absorbing clouds at distances 11-13kpc from the Sun in the minor
Carina-Sagittarius Arm.
Description:
VJHKs photometry of stars in two VIMOS disc fields: F167 and F170.
Data table with 333 variables detected in the field F170 in Centaurus.
The optical observations were taken with the 8.2-m Unit Telescope 3 +
VIMOS imager with a scale of 0.205"/pix at ESO Very Large Telescope at
Paranal Observatory. Date of the observations: Apr 11-12, 2005. The
infrared observations were obtained with the 4.1-m VISTA telescope +
VIRCAM with a scale of 0.34"/pix also at Paranal Observatory.
Date of the observations: Mar-Apr 2010.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
f167phot.dat 121 89694 Photometry of all stars detected in F167
f170phot.dat 121 84734 Photometry of all stars detected in F170
f170var.dat 78 333 Data on detected variables
phot/* . 333 Individual time-series photometry of the variables
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Byte-by-byte Description of file: f167phot.dat f170phot.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq [1/89694] Star identification number
8- 17 F10.6 deg RAdeg Right ascension J2000 (degrees)
19- 28 F10.6 deg DEdeg Declination J2000 (degrees)
31- 36 F6.3 mag Vmag V magnitude
38- 42 F5.3 mag e_Vmag V magnitude error
44- 49 F6.3 mag Jmag ?=99.999 J magnitude (G1)
51- 55 F5.3 mag e_Jmag ?=9.999 J magnitude error (G1)
57- 62 F6.3 mag Hmag ?=99.999 H amplitude (G1)
64- 68 F5.3 mag e_Hmag ?=9.999 H amplitude error (G1)
70- 75 F6.3 mag Ksmag ?=99.999 Ks magnitude (G1)
77- 81 F5.3 mag e_Ksmag ?=9.999 Ks magnitude error (G1)
84- 89 F6.3 mag V-K ?=99.999 V-K color index (G1)
91- 95 F5.3 mag e_V-K ?=9.999 V-K color index error (G1)
97-102 F6.3 mag V-J ?=99.999 V-J color index (G1)
104-108 F5.3 mag e_V-J ?=9.999 V-J color index error (G1)
110-115 F6.3 mag J-K ?=99.999 J-K color index (G1)
117-121 F5.3 mag e_J-K ?=9.999 J-K color index error (G1)
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Byte-by-byte Description of file: f170var.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- VName Variable identification number (VNNN)
6- 7 I2 h RAh Right ascension J2000 (hours)
9- 10 I2 min RAm Right ascension J2000 (minutes)
12- 16 F5.2 s RAs Right ascension J2000 (seconds)
18 A1 --- DE- Declination J2000 (sign)
19- 20 I2 deg DEd Declination J2000 (degrees)
22- 23 I2 arcmin DEm Declination J2000 (minutes)
25- 28 F4.1 arcsec DEs Declination J2000 (seconds)
30- 35 F6.4 d Per ?=9.9999 Period (G1)
37- 41 F5.2 mag Vmag V magnitude
43- 48 F6.3 mag Jmag ?=99.999 J magnitude (G1)
50- 55 F6.3 mag Hmag ?=99.999 H amplitude (G1)
57- 62 F6.3 mag Ksmag ?=99.999 Ks magnitude (G1)
64- 66 A3 --- VType Variable type (2)
68- 78 A11 --- OName Other name, if exists
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Note (2): The following abbreviations are used for different types of variables:
ecl = eclipsing/ellipsoidal
del = delta Scuti type
pul = other pulsating variable
lon = long-time scale variable
flr = flaring object
tra = transiting object
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Byte-by-byte Description of file: phot/*
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Bytes Format Units Label Explanations
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2- 13 F12.6 d MJD Modified Julian Date
16- 21 F6.3 mag Vmag V magnitude
24- 28 F5.3 mag e_Vmag V magnitude error
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Global notes:
Note (G1): Magic numbers 9.999 and 99.999 mean no estimation.
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Acknowledgements:
Pawel Pietrukowicz,
Warsaw University Observatory, Poland, pietruk(at)astrouw.edu.pl
(End) Pawel Pietrukowicz [Warsaw, Poland], Patricia Vannier [CDS] 17-Oct-2011