J/ApJ/777/79 HST photometry of Cepheid candidates in M101 (Mager+, 2013)
The metallicity dependence of the cepheid P-L relation in M101.
Mager V.A., Madore B.F., Freedman W.L.
<Astrophys. J., 777, 79 (2013)>
=2013ApJ...777...79M 2013ApJ...777...79M
ADC_Keywords: Photometry, HST ; Abundances ; Stars, variable
Keywords: galaxies: distances and redshifts; galaxies: individual: M101;
stars: variables: Cepheids
Abstract:
The impact of metallicity on the Cepheid period-luminosity (P-L)
relation is investigated using Hubble Space Telescope Advanced Camera
for Surveys V and I images of M101. Variations in the reddening-free
Wesenheit parameter (W), which is employed as a proxy for luminosity,
are examined as a function of the radial distance from the center of
M101 (and thus metallicity). We determine that there is no dependence
of the slope on metallicity. However, the intercept is found to depend
on metallicity by γVI=-0.33±0.12mag.dex-1 and
γVI=-0.71±0.17mag.dex-1 using 2σ and 3σ
rejection criteria, respectively. Sigma-clipping impacts the derived
metallicity dependence, and the 2σ criterion applied likely
mitigates blending, particularly in the crowded inner regions of M101.
A metallicity-corrected distance for M101 is obtained from 619
Cepheids (µ=28.96±0.11), a result that agrees with the recently
determined SN Ia distance. The metallicity effects described can be
bypassed by working at near and mid-infrared wavelengths (e.g., the
Carnegie Hubble Program).
Description:
Two separate fields in M101 were observed with the HST/ACS Wide Field
Camera. Each field was visited on 12 occasions ranging from ∼1-5 days
apart; in both F814W and F555W.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 619 Measured quantities for candidate cepheids
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/AJ/146/114 : Massive stars in M101. I. HST BVI photometry (Grammer+, 2013)
J/ApJ/759/146 : Spitzer/IRAC photom. for 37 Galactic Cepheids (Monson+, 2012)
J/ApJ/743/176 : BVI photometry of Cepheids in M81 (Gerke+, 2011)
J/ApJ/743/76 : Spitzer photometry of LMC Cepheids (Scowcroft+, 2011)
J/ApJ/733/124 : Cepheids in M101 observed with HST (Shappee+, 2011)
J/ApJS/193/26 : The M33 synoptic stellar survey. I. (Pellerin+, 2011)
J/ApJ/715/277 : Insights into the Cepheid distance scale (Bono+, 2010)
J/AcA/60/17 : VI light curves of SMC classical Cepheids (Soszynski+, 2010)
J/ApJ/699/539 : Cepheids in SN-Ia host galaxies (Riess+, 2009)
J/AcA/58/163 : VI light curves of LMC classical Cepheids (Soszynski+, 2008)
J/AJ/128/2239 : JHKs photometry of 92 LMC Cepheids (Persson+, 2004)
J/AcA/51/221 : OGLE-II. Cepheids in IC 1613 (Udalski+, 2001)
J/ApJ/508/491 : M101 Cepheids (Stetson+, 1998)
J/ApJ/463/26 : VI photometry of 29 Cepheids in M101. (Kelson+ 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- --- [F]
2 I1 --- F HST field number (F1 or F2; see Figure 1)
4- 14 A11 --- ID Source identifier (chNNsNNNN)
16- 24 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
26- 34 F9.6 deg DEdeg Declination in decimal degrees (J2000)
36- 41 F6.3 mag Vmag [23.4/26.2] The average HST/ACS V band magnitude
43- 47 F5.3 mag e_Vmag [0.009/0.05] Uncertainty in Vmag
49- 54 F6.3 mag Imag [22.6/25.5] The average HST/ACS I band magnitude
56- 60 F5.3 mag e_Imag [0.006/0.04] Uncertainty in Imag
62- 66 F5.2 d Per [4.5/29.8] Period
68- 72 F5.3 mag Vamp [0.2/1.6] The V band amplitude
74- 78 F5.3 mag Iamp [0.1/2.8] The I band amplitude
80- 84 F5.3 arcmin r [1/5.4] Angular radial distance from
galaxy center
86- 91 F6.3 [-] [O/H] [-3.6/-3.3] Log O/H metallicity
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 07-Apr-2015