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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
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:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        69       17   Cepheids in NGC 7793
table1.dat        35     1254   Individual V and I Observations


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

   Bytes Format Units   Label     Explanations

   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)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label     Explanations

   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


History:
    From electronic version of the journal
(End)                  Greg Schwarz [AAS], Patricia Vannier [CDS]    07-Jul-2012