J/A+A/450/873 Araucaria: NGC 6822 bright variables VI phot. (Mennickent+, 2006)
The Araucaria project.
Bright variable stars in NGC 6822 from a wide-field imaging survey.
Mennickent R.E., Gieren W., Soszynski I., Pietrzynski G.
<Astron. Astrophys. 450, 873 (2006)>
=2006A&A...450..873M 2006A&A...450..873M
ADC_Keywords: Stars, variable ; Photometry, CCD
Keywords: galaxies: stellar content - binaries: eclipsing -
stars: variables: general - Cepheids - Local Group - binaries: general
Abstract:
We have performed a search for variable stars in the dwarf irregular
galaxy NGC 6822 using wide-field multi-epoch VI photometry down to a
limiting magnitude of ∼22. A part from the Cepheid variables in this
galaxy already reported in an earlier paper by Pietrzynski et al.
(2004AJ....128.2815P 2004AJ....128.2815P), we have found 1019 "non-periodic" variable
stars, 50 periodically variable stars with periods ranging from 0.12
to 66 days and 146 probably periodic variables. Twelve of these stars
are eclipsing binaries and fifteen are likely new, low-amplitude
Cepheids.
Description:
VI Photometry of NGC 6822 from a wide-field imaging survey
(Pietrzynski et al., 2004AJ....128.2815P 2004AJ....128.2815P). Monitoring at the Warsaw
1.3m telescope at Las Campanas Observatory during 77 nights, spread
over nearly one year, with the aid of mosaic images (35x35 squared
arcminutes).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 120 50 Periodically variable stars towards NGC 6822
table2.dat 63 146 Candidates for periodic stars towards NGC 6822
table3.dat 66 1019 *"Non-periodic" variable stars towards NGC 6822
tables.tex 132 1543 LaTeX version of the tables
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Note on table3.dat : Many of these variables may turn out to be periodic once
the time baseline of the observations will be extended.
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See also:
J/AJ/123/789 : Araucaria: NGC 300 Cepheid variables (Pietrzynski+, 2002)
J/MNRAS/350/679 : Araucaria: BV phot. of NGC 300 variables (Mennickent+, 2004)
J/AJ/128/1167 : Araucaria: NGC 300 Cepheid Variables. II (Gieren+, 2004)
J/AJ/121/2020 : CTIO and WFPC2 photometry in NGC 6822 (Bianchi+, 2001)
J/AJ/128/2815 : Araucaria: NGC 6822 Cepheid variables (Pietrzynski+, 2004)
J/A+A/431/1189 : BV photometry of NGC 6822 variables (Baldacci+, 2005)
J/ApJ/647/1056 : Araucaria: NGC 6822 Cepheid variables (Gieren+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- Seq Identification number (NNNNN-N)
9- 10 I2 h RAh Right ascension (J2000.0)
12- 13 I2 min RAm Right ascension (J2000.0)
15- 19 F5.2 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 31 F4.1 arcsec DEs Declination (J2000.0)
33- 36 F4.2 mag AmpI Amplitude in the I band
38- 45 F8.5 d Per Period
47- 54 F8.5 d E_Per Error in Per (upper limit)
56- 62 F7.5 d e_Per Error in Per (lower limit)
63- 64 A2 --- n_Per [e MA] Note on Per (1)
67- 72 F6.4 d Per2 ? Second value of possible period (Per or Per2)
74- 79 F6.4 d e_Per2 ? rms uncertainty on Per2
81- 85 F5.2 mag IMAG Absolute I magnitude
87- 91 F5.2 mag (V-I)0 ?=- Dereddened V-I colour index
93- 97 F5.2 mag Imag ?=- Mean I magnitude
99-103 F5.2 mag Vmag ?=- Mean V magnitude
105-113 F9.4 d T0 Time of maxima (or main minima, in the case of
eclipsing binaries) in Julian Date -2450000
115-120 F6.4 d e_T0 rms uncertainty on T0
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Note (1): Notes on periods as follows:
e = the stars is an eclipsing binary
MA = multiple aliases
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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- 7 A7 --- Seq Identification number (NNNNN-N)
9- 10 I2 h RAh Right ascension (J2000.0)
12- 13 I2 min RAm Right ascension (J2000.0)
15- 19 F5.2 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 31 F4.1 arcsec DEs Declination (J2000.0)
33- 35 I3 d T Time scale of variability in I-band
37- 40 F4.2 mag AmpI Amplitude in the I band
42- 46 F5.2 mag Imag0 Dereddened I magnitude
48- 51 F4.2 mag (V-I)0 ?=- Dereddened V-I colour index
53- 57 F5.2 mag Imag Mean I magnitude
59- 63 F5.2 mag Vmag ?=- Mean V magnitude
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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- 5 I5 --- Star Identification number of the star
7 I1 --- Field Field number
9- 10 I2 h RAh Right ascension (J2000.0)
12- 13 I2 min RAm Right ascension (J2000.0)
15- 19 F5.2 s RAs Right ascension (J2000.0)
21 A1 --- DE- Declination sign (J2000.0)
22- 23 I2 deg DEd Declination (J2000.0)
25- 26 I2 arcmin DEm Declination (J2000.0)
28- 31 F4.1 arcsec DEs Declination (J2000.0)
33- 36 F4.2 mag AmpI Amplitude in the I band
38- 42 F5.2 mag IMAG Absolute I magnitude
44- 48 F5.2 mag (V-I)0 ?=- Dereddened V-I colour index
50- 54 F5.2 mag Imag Mean I magnitude
56- 60 F5.2 mag Vmag ?=- Mean V magnitude
62- 66 F5.2 --- S/N Ratio between the amplitude of the highest peak
in the periodogram and the noise amplitude
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Historical notes:
* 11-Apr-2006: Original version
* 03-Jan-2008: Corrected version of table1 (for I and V magnitudes)
from the author
Acknowledgements:
Ronald Mennickent, rmennick(at)astro-udec.cl
(End) Patricia Vannier [CDS] 17-Jan-2006