J/MNRAS/454/507 Short-period var. stars OmegaWhite survey (Macfarlane+, 2015)
The OmegaWhite survey for short-period variable stars.
I. Overview and first results.
Macfarlane S.A., Toma R., Ramsay G., Groot P.J., Woudt P.A., Drew J.E.,
Barentsen G., Eisloffel J.
<Mon. Not. R. Astron. Soc., 454, 507-530 (2015)>
=2015MNRAS.454..507M 2015MNRAS.454..507M (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Milky Way ; Stars, variable ; Photometry
Keywords: methods: data analysis - methods: observational -
techniques: photometric - surveys - binaries: close - Galaxy: bulge
Abstract:
We present the goals, strategy and first results of the OmegaWhite
survey: a wide-field high-cadence g-band synoptic survey which aims to
unveil the Galactic population of short-period variable stars (with
periods <80min), including ultracompact binary star systems and
stellar pulsators. The ultimate goal of OmegaWhite is to cover
400deg2 along the Galactic plane reaching a depth of g=21.5mag
(10σ), using OmegaCam on the VLT Survey Telescope (VST). The
fields are selected to overlap with surveys such as the Galactic Bulge
Survey and the VST Photometric Hα Survey of the Southern
Galactic Plane for multiband colour information. Each field is
observed using 38 exposures of 39s each, with a median cadence of
∼2.7min for a total duration of two hours. Within an initial 26deg2,
we have extracted the light curves of 1.6 million stars, and have
identified 613 variable candidates which satisfy our selection
criteria. Furthermore, we present the light curves and statistical
properties of 20 sources which have the highest likelihood of being
variable stars. One of these candidates exhibits the colours and
light-curve properties typically associated with ultracompact AM CVn
binaries, although its spectrum exhibits weak Balmer absorption lines
and is thus not likely to be such a binary system. We also present
follow-up spectroscopy of five other variable candidates, which
identifies them as likely low-amplitude δ Sct pulsating stars.
Description:
OmegaWhite observations are taken in g band using the wide-field
instrument OmegaCAM on the VST. The VST is a 2.65-m wide-field survey
telescope situated at the ESO Paranal Observatory in Northern Chile.
The sole instrument on the telescope, OmegaCAM is a 16kx16k imaging
camera, covering one square degree with 32 CCDs (each 2kx4k) at a
plate scale of 0.216arcsec/pix.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea2.dat 82 613 Parameters of the 613 variable candidates
(selected using n=15)
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See also:
J/MNRAS/429/385 : Short-period variables near Galactic Centre (Matsunaga+ 2013)
Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [OW]
4- 22 A19 --- OW OW designation (JHHMMSS.ss+DDMMSS.s)
24- 25 I2 h RAh Right ascension (J2000)
27- 28 I2 min RAm Right ascension (J2000)
30- 34 F5.2 s RAs Right ascension (J2000)
36 A1 --- DE- Declination sign (J2000)
37- 38 I2 deg DEd Declination (J2000)
40- 41 I2 arcmin DEm Declination (J2000)
43- 46 F4.1 arcsec DEs Declination (J2000)
48- 53 F6.2 min PLS Lomb-Scargle period of the highest peak in
the periodogram
55- 59 F5.2 [-] log10(FAP) False alarm probability (FAP) of the highest
peak in the periodogram
61- 65 F5.2 mag OWgmag OW calibrated g-band magnitude
67- 71 F5.3 mag e_OWgmag rms uncertainty on OWgmag
73- 76 F4.2 mag g-r ? VPHAS+ g-r colour index
78- 82 F5.2 mag u-g ? VPHAS+ u-g colour index
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Jun-2016