J/AJ/140/1475 ARAUCARIA: NGC 7793 Cepheids (Pietrzynski+, 2010)
The ARAUCARIA project: first Cepheid distance to the Sculptor group galaxy
NGC 7793 from variables discovered in a wide-field imaging survey.
Pietrzynski G., Gieren W., Hamuy M., Pignata G., Soszynski I., Udalski A.,
Walker A., Fouque P., Bresolin F., Kudritzki R.-P., Garcia-Varela A.,
Szewczyk O., Szymanski M., Kubiak M., Wyrzykowski L.
<Astron. J., 140, 1475-1485 (2010)>
=2010AJ....140.1475P 2010AJ....140.1475P
ADC_Keywords: Galaxies, nearby ; Stars, variable ; Photometry, VRI
Keywords: distance scale - galaxies: distances and redshifts -
galaxies: individual (NGC 7793) - galaxies: stellar content -
stars: variables: Cepheids
Abstract:
For the first time, we have detected Cepheid variables in the Sculptor
Group spiral galaxy NGC 7793. From wide-field images obtained in the
optical V and I bands on 56 nights in 2003-2005, we have discovered 17
long-period (24-62 days) Cepheids whose periods and mean magnitudes
define tight period-luminosity relations. We use the (V-I) Wesenheit
index to determine a reddening-free true distance modulus to NGC 7793
of 27.68±0.05mag (internal error) ±0.08mag (systematic error).
Description:
All the data presented in this paper were collected with the Warsaw
1.3m telescope at Las Campanas Observatory. The observations were
obtained between 2003 July and 2005 December.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 69 17 Cepheids in NGC 7793
table1.dat 35 1254 Individual V and I Observations
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See also:
J/A+A/440/783 : OB associations in NGC 7793 (Pietrzynski+, 2005)
J/AJ/135/1993 : JHK magnitudes of Sculptor dSph RR Lyrae (Pietrzynski+, 2008)
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 Star name, cepNNN ([PGH2010] cepNNN in Simbad)
8- 9 I2 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 18 F5.2 s RAs Right ascension (J2000)
20 A1 --- DE- Declination sign (J2000)
21- 22 I2 deg DEd Declination (J2000)
24- 25 I2 arcmin DEm Declination (J2000)
27- 30 F4.1 arcsec DEs Declination (J2000)
32- 38 F7.4 d Per Period
40- 48 F9.4 d T0 Epoch of minimum (T0-2450000)
50- 55 F6.3 mag <Vmag> Mean V magnitude
57- 62 F6.3 mag <Imag> ?=- Mean I magnitude
64- 69 F6.3 mag <WImag> ?=- Mean Wesenheit WI magnitude,
defined as WI=I-1.55(V-I)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Star name, cepNNN
8 A1 --- Filter [VI] Filter used in observation
10- 22 F13.5 d HJD Heliocentric Julian Date
24- 29 F6.3 mag mag Observed magnitude in Filter
31- 35 F5.3 mag e_mag Uncertainty in mag
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 07-Jul-2012