J/A+A/671/A157 MW, SMC and LMC classical Cepheids metallicity (Hocde+, 2023)
Metallicity estimations of MW, SMC, and LMC classical Cepheids from the shape
of the V- and I-band light curves.
Hocde V., Smolec R., Moskalik P., Ziolkowska O., Singh Rathour R.
<Astron. Astrophys. 671, A157 (2023)>
=2023A&A...671A.157H 2023A&A...671A.157H (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Magellanic Clouds ; Stars, variable ;
Abundances, [Fe/H] ; Optical
Keywords: stars: variables: Cepheids - Galaxy: abundances -
techniques: photometric - techniques: spectroscopic -
Magellanic Clouds - methods: data analysis
Abstract:
Estimating the metallicity of classical Cepheids is of prime
importance for studying metallicity effects on stellar evolution and
the chemical evolution of galaxies, as well as on the
period-luminosity relation used on the extragalactic distance scale.
Our first aim is to establish new empirical relations for estimating
the iron content of classical Cepheids for short and long periods
based on Fourier parameters from the V- and I-band light curves.
We go on to apply these relations to Cepheids from data on the Milky
Way (MW) as well as the Small and Large Magellanic Clouds (SMC and
LMC) from the literature.
We retrieved the metallicities of 586 fundamental-mode Cepheids from
spectroscopic determinations in the literature and we found
well-sampled light curves for 545 of them in different V-band
catalogs. We then described the shape of these light curves by
applying a Fourier decomposition and we fit the empirical relations
between the Fourier parameters and the spectroscopic metallicities
individually, for short-period (2.5<P<6.3-days) and long-period
Cepheids (12<P<40-days). We verified the accuracy of these
relations by applying them to V-band light curves of Cepheids from
the Small and Large Magellanic Clouds and comparing these derived
metallicities to literature values. We calibrated new interrelations
of Fourier parameters to convert these empirical relations into the
I band. We then used these I-band relations to derive the
metallicity of fundamental-mode Cepheids from OGLE-IV for MW, SMC, and
LMC (486, 695, and 1697 stars, respectively). Finally, we mapped the
metallicity distribution in these galaxies for the purpose of
investigating potential applications in galactic archeology.
For short-period Cepheids, our best fit is given for a relation based
on explicit amplitude terms A1 and A2 of the first and second
harmonic, respectively. In the V and I bands, these empirical
relations are found with an intrinsic scatter (rms) of 0.12dex. This
relation performs well for estimations of [Fe/H] between about -0.5
and 0.1dex, but it remains uncertain outside this range because of the
lack of a spectroscopic metallicity required for the calibration. For
long-period Cepheids, we found a metallicity dependence on the Fourier
parameters A1, phi21, and R41. We found an intrinsic scatter of
0.25dex when using this relation.
The empirical relations in the V and I bands allow us to derive
the mean metallicity of a sample of MW, SMC, and LMC Cepheids that is
in agreement with literature values within 1σ. We also show
that these relations are precise enough to reconstruct the radial
metallicity gradients within the MW from OGLE data. The empirical
relations in the V and I bands that are calibrated in this work
for short- and long-period Cepheids provide a useful new tool for
estimating the metallicity of Cepheids that are not accessible via
spectroscopy. The calibration can be improved with further
high-resolution spectroscopic observations of metal-poor Cepheids and
homogeneous photometries in the V and I bands.
Description:
We provide the calibration sample composed of low-order Fourier
coefficients from V-band light curves of 545 Cepheids together with
metallicity determined from high-resolution spectroscopy gathered from
literature. We also provide metallicity estimations from the I-band
light curves for MW, LMC and SMC Cepheids.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 103 545 Calibration sample of the V-band empirical
relation
tablea2.dat 48 486 Metallicity estimations of 486 MW Cepheids
from OGLE I-band (Galactic Disk + Bulge)
tablea3.dat 48 1697 Metallicity estimations of 1697 LMC Cepheids
from OGLE I-band light curves
tablea4.dat 48 695 Metallicity estimations of 695 SMC Cepheids
from OGLE I-band light curves
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 28 A28 --- Name Star name
30- 37 A8 --- Source V-band light curve reference (1)
39- 44 F6.3 d Period Period derived using Lomb-Scargled method
46- 51 F6.3 [-] [Fe/H] High-resolution spectroscopy scaled to solar
abundance A(Fe)=7.50
53- 55 A3 --- Ref Reference of [Fe/H] value (2)
57- 61 F5.3 mag A1 Amplitude of the first harmonic
from Fourier decomposition
63- 67 F5.3 rad phi21 Fourier phase phi21=phi2-2phi1
69- 73 F5.3 rad phi31 Fourier phase phi31=phi3-3phi1
75- 79 F5.3 rad phi41 Fourier phase phi41=phi4-4phi1
81- 85 F5.3 --- R21 Amplitude ratio R21=A2/A1
87- 91 F5.3 --- R31 Amplitude ratio R31=A3/A1
93- 97 F5.3 --- R41 Amplitude ratio R41=A4/A1
99-103 F5.3 mag sigma Fourier fit uncertainty of the V-band
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Note (1): V-band references as follows:
ASAS-SN = Jayasinghe et al., 2018MNRAS.477.3145J 2018MNRAS.477.3145J, Cat. II/366
ASAS = Pojmanski, 2002AcA....52..397P 2002AcA....52..397P, Cat. II/264
BER08 = Berdnikov 2008, Cat. II/285
OGLE-III = Soszynski et al., 2008AcA....58..163S 2008AcA....58..163S, Cat. J/AcA/58/163
OGLE-IV = Soszynski et al., 2010AcA....60...17S 2010AcA....60...17S, Cat. J/AcA/60/17
Note (2): [Fe/H] references as follows:
L18 = Luck (2018AJ....156..171L 2018AJ....156..171L, Cat. J/AJ/156/171) (re-scaled to
solar values, then used as a reference for offset correction of
Galactic Cepheids from others source)
L11 = Luck & Lambert (2011AJ....142..136L 2011AJ....142..136L, Cat. J/AJ/142/136),
compiled by Groenewegen, 2018A&A...619A...8G 2018A&A...619A...8G, Cat. J/A+A/619/A8
(-0.071 offset correction)
G14 = Genovali et al., (2014A&A...566A..37G 2014A&A...566A..37G, Cat. J/A+A/566/A37),
compiled by Groenewegen, 2018A&A...619A...8G 2018A&A...619A...8G, Cat. J/A+A/619/A8
(-0.071 offset correction)
G15 = Genovali et al., (2015A&A...580A..17G 2015A&A...580A..17G, Cat. J/A+A/580/A17),
compiled by Groenewegen, 2018A&A...619A...8G 2018A&A...619A...8G, Cat. J/A+A/619/A8
(-0.071 offset correction)
M15 = Martin et al., 2015MNRAS.449.4071M 2015MNRAS.449.4071M, compiled by Groenewegen,
2018A&A...619A...8G 2018A&A...619A...8G, Cat. J/A+A/619/A8
(-0.071 offset correction)
A16 = Andrievsky et al., 2016MNRAS.461.4256A 2016MNRAS.461.4256A, compiled by Groenewegen,
2018A&A...619A...8G 2018A&A...619A...8G, Cat. J/A+A/619/A8
(-0.071 offset correction)
T22 = Trentin et al., 2022MNRAS.519.2331T 2022MNRAS.519.2331T, no offset applied
K22 = Kovtyukh et al., 2022MNRAS.510.1894K 2022MNRAS.510.1894K, (-0.06 offset correction)
R21 = Ripepi et al., 2021MNRAS.508.4047R 2021MNRAS.508.4047R, Cat. J/MNRAS/508/4047,
no offset applied
L17 = Lemasle et al., 2017A&A...608A..85L 2017A&A...608A..85L, LMC and SMC Cepheids
R08 = Romaniello et al., 2008A&A...488..731R 2008A&A...488..731R, SMC Cepheids corrected
from possible offset of -0.11 dex (see Romaniello et al.,
2022A&A...658A..29R 2022A&A...658A..29R, Cat. J/A+A/658/A29).
R22 = Romaniello et al., 2022A&A...658A..29R 2022A&A...658A..29R, Cat. J/A+A/658/A29,
LMC Cepheids
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Byte-by-byte Description of file: tablea2.dat tablea3.dat tablea4.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Name Star name
19- 20 I2 h RAh Right Ascension (J2000)
22- 23 I2 min RAm Right Ascension (J2000)
25- 29 F5.2 s RAs Right Ascension (J2000)
31 A1 --- DE- Declination sign (J2000)
32- 33 I2 deg DEd Declination (J2000)
35- 36 I2 arcmin DEm Declination (J2000)
38- 41 F4.1 arcsec DEs Declination (J2000)
43- 48 F6.3 --- [Fe/H] Estimated [Fe/H] from OGLE I-band LC (1)
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Note (1): Metallicity estimations in the I-band are estimated as follows:
For tablea2.dat:
- For short-period Cepheids:
[Fe/H] = (10.69±0.90)A1 + (-19.96±1.58)A2 -0.60±0.07)
- For long-period Cepheids:
[Fe/H] = (6.43±0.76)A1+(-6.03±0.89)R41+(-0.77±0.13)phi21+(1.66±0.40)
For tablea3.dat:
- For short-period Cepheids:
[Fe/H]=10.69 A1+(-19.96)A2-0.60
- For long-period Cepheids:
[Fe/H]=6.43A1-6.03R41-0.77phi21+1.66
With individual uncertainties of 0.12 and 0.25dex for short and long-periods
respectively, derived from the rms of these relations.
For tablea4.dat:
- For short-period Cepheids :
[Fe/H]=10.69A1-19.96A2-0.60±0.07
- For long-period Cepheids :
[Fe/H]=6.43A1-6.03R41-0.77phi21+1.66
With individual uncertainties of 0.12 and 0.25dex for short and long-periods
respectively, derived from the rms of these relations.
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Acknowledgements:
Vincent Hocde, vhocde(at)camk.edu.pl
(End) Patricia Vannier [CDS] 21-Feb-2023