J/ApJ/715/277       Insights into the Cepheid distance scale       (Bono+, 2010)
Insights into the Cepheid distance scale.
    Bono G., Caputo F., Marconi M., Musella I.
   <Astrophys. J., 715, 277-291 (2010)>
   =2010ApJ...715..277B 2010ApJ...715..277B
ADC_Keywords: Galaxies, nearby ; Abundances ; Stars, variable ; Stars, distances
Keywords: Galaxy: disk - Local Group - Magellanic Clouds - stars: distances -
          stars: oscillations - stars: variables: Cepheids
Abstract:
    We present a detailed investigation of the Cepheid distance scale by
    using both theory and observations. Through the use of pulsation
    models for fundamental mode Cepheids, we found that the slope of the
    period-luminosity (P-L) relation covering the entire period range
    (0.40≤logP≤2.0) becomes steeper when moving from optical to
    near-infrared (NIR) bands, and that the metallicity dependence of the
    slope decreases from the B- to the K band. The sign of the metallicity
    dependence for the slopes of the P-LV and P-LI relation is at odds
    with some recent empirical estimates. We determined new homogeneous
    estimates of V- and I-band slopes for 87 independent Cepheid data sets
    belonging to 48 external galaxies with nebular oxygen abundance
    7.5≤12+log(O/H)≤8.9. We investigated the dependence of the
    period-Wesenheit (P-W) relations on the metal content and we found
    that the slopes of optical and NIR P-W relations in external galaxies
    are similar to the slopes of Large Magellanic Cloud (LMC) Cepheids.
    They also agree with the theoretical predictions suggesting that the
    slopes of the P-W relations are independent of the metal content.
File Summary:
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 FileName   Lrecl  Records   Explanations
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ReadMe         80        .   This file
sample.dat     31       50   Galaxy sample
table7.dat     29       52   Galaxy metal abundances
table8.dat     53       87   Slopes b(V) and b(I) of observed P-L relations
                             estimated using Cepheids with 0.5≤logP≤2.0
table15.dat    81       87   Distance moduli µ0(WVI) for the galaxies
                             listed in Table 8
refs.dat      164       41   References
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See also:
 J/A+A/534/A94  : Milky Way Cepheids radial velocities (Storm+, 2011)
 J/A+A/534/A95  : LMC Cepheids radial velocities (Storm+, 2011)
 J/A+A/508/355  : Scaled solar tracks and isochrones (Bertelli+, 2009)
 J/ApJS/183/109 : Cepheids in 3 host galaxies (Riess+, 2009)
 J/ApJ/679/71   : Mid-IR period-luminosity relations (Freedman+, 2008)
 J/A+A/476/73   : Calibration of Cepheid Period/Luminosity relation (Fouque+,
                  2007)
 J/ApJ/647/1056 : ARAUCARIA project : NGC 6822 Cepheid variables (Gieren+, 2006)
 J/AJ/128/2239  : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)
 J/A+A/411/361  : VI photometry of extra-galactic Cepheids (Kanbur+, 2003)
 J/A+A/404/423  : BVI photometry of Galactic Cepheids (Tammann+, 2003)
 J/ApJS/142/71  : BVRI observations of LMC Cepheids (Sebo+, 2002)
 J/AcA/51/221   : OGLE-II. Cepheids in IC 1613 (Udalski+, 2001)
 J/A+AS/143/211 : Galactic Cepheids BVRI photometry (Berdnikov+, 2000)
 J/A+AS/141/371 : Low-mass stars evolutionary tracks + isochrones (Girardi+,
                  2000)
 http://www.ipac.caltech.edu/H0kp/ : HST Key Project on the extragalactic
                  distance scale home page
 http://sites.google.com/site/araucariaproject/ : Araucaria Project home page
Byte-by-byte Description of file: sample.dat
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   Bytes Format Units   Label     Explanations
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   1-  6  A6    ---     Name      Galaxy name
   9- 10  I2    h       RAh       ? SIMBAD hour of right ascension (J2000)
  12- 13  I2    min     RAm       ? SIMBAD minute of right ascension (J2000)
  15- 19  F5.2  s       RAs       ? SIMBAD second of right ascension (J2000)
      21  A1    ---     DE-       ? SIMBAD sign of declination (J2000)
  22- 23  I2    deg     DEd       ? SIMBAD degree of declination (J2000)
  25- 26  I2    arcmin  DEm       ? SIMBAD arcminute of declination (J2000)
  28- 31  F4.1  arcsec  DEs       ? SIMBAD arcsecond of declination (J2000)
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  6  A6    ---     Name      Galaxy name
       7  A1    ---   f_Name      Flag on name (G1)
   9- 13  A5    ---   r_Mold      Reference for Mold (see refs.dat file)
  15- 18  F4.2  [-]     Mold      Old metal abundance (12+log(O/H))
  20- 23  F4.2  [-]   e_Mold      Uncertainty in Mold
  25- 28  F4.2  [-]     Mnew      New metal abundance (12+log(O/H))
      29  A1    ---   f_Mnew      [*] estimated Mnew (1)
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Note (1):
    * = Estimated using the polynomial regression presented in Fig. 7
        (see text for more details).
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Byte-by-byte Description of file: table8.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  6  A6    ---     Name      Galaxy name
   7-  8  A2    ---   f_Name      Flag on Name (G1)
  10- 13  F4.2  [-]     Met       ? Metalicity
  15- 19  F5.2  ---     b(V)      V band slope in P-L relationship
  21- 24  F4.2  ---   e_b(V)      Uncertainty in b(V)
  26- 30  F5.2  ---     b(I)      ? I band slope in P-L relationship
  32- 35  F4.2  ---   e_b(I)      ? Uncertainty in b(I)
  37- 41  F5.2  ---     beta      ? Slope of observed P-WVI relationship
  43- 46  F4.2  ---   e_beta      ? Uncertainty in beta
  48- 53  A6    ---     Refs      Reference(s) (see refs.dat file)
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Byte-by-byte Description of file: table15.dat
--------------------------------------------------------------------------------
   Bytes Format Units   Label    Explanations
--------------------------------------------------------------------------------
   1-  6  A6    ---     Name     Galaxy name
   9- 11  A3    ---   n_Name     Flag on Name (G1)
  13- 18  A6    ---   r_m-M      Reference(s) on m-M (see refs.dat file)
  20- 24  F5.2  mag     LMCm-M   ? LMC distance modulus adopted in the original
                                 paper (r_m-M)
  26- 30  F5.2  mag     m-M      ? Distance modulus
  32- 35  F4.2  mag   e_m-M      ? Uncertainty in m-M
  37- 41  F5.2  mag     Fr01     ? Freedman et al. 2001ApJ...553...47F 2001ApJ...553...47F distance
                                 modulus
  43- 46  F4.2  mag   e_Fr01     ? Uncertainty in Fr01
  48- 52  F5.2  mag     Ka03     ? Kanbur et al. 2003, Cat. J/A+A/411/361,
                                 distance modulus
  54- 57  F4.2  mag   e_Ka03     ? Uncertainty in Ka03
  59- 63  F5.2  mag     STT06    ? Saha et al. 2006ApJS..165..108S 2006ApJS..165..108S distance
                                 modulus
      65  A1    ---   f_STT06    [c] c: distance modulus from Sandage & Tammann
                                 2008ApJ...686..779S 2008ApJ...686..779S
  67- 70  F4.2  mag   e_STT06    ? Uncertainty in STT06
  72- 76  F5.2  mag     Our      ? Distance modulus from this paper
  78- 81  F4.2  mag   e_Our      ? Uncertainty in Our
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Byte-by-byte Description of file: refs.dat
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   Bytes Format Units   Label     Explanations
--------------------------------------------------------------------------------
   1-  6  A6    ---     Ref       Reference code
   8- 26  A19   ---     BibCode   Bibcode
  28- 47  A20   ---     Aut       Author's name(s)
  49-164  A116  ---     Comm      Comment
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Global notes:
Note (G1):
    i = inner field Cepheids;
    o = outer field Cepheids;
    * = <20 Cepheids.
    a = Data from Freedman (1988ApJ...326..691F 1988ApJ...326..691F);
    b = Data from Freedman et al. (1991ApJ...372..455F 1991ApJ...372..455F).
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History:
    From electronic version of the journal
(End)                 Greg Schwarz [AAS], Emmanuelle Perret [CDS]    26-Apr-2012