J/A+A/619/A8 Cepheid period-luminosity-metallicity relation (Groenewegen, 2018)
The Cepheid period-luminosity-metallicity relation based on Gaia DR2 data.
Groenewegen M.A.T.
<Astron. Astrophys. 619, A8 (2018)>
=2018A&A...619A...8G 2018A&A...619A...8G (SIMBAD/NED BibCode)
ADC_Keywords: Stars, distances; Parallaxes, trigonometric
Keywords: stars: distances - Cepheids - distance scale - parallaxes
Abstract:
We use parallax data from the Gaia second data release (GDR2),
combined with parallax data based on HIPPARCOS and HST data, to derive
the period-luminosity-metallicity (PLZ) relation for Galactic
classical cepheids (CCs) in the V, K, and Wesenheit WVK bands.
An initial sample of 452 CCs are extracted from the literature with
spectroscopically derived iron abundances. Reddening values,
classifications, pulsation periods, and mean V- and K-band magnitudes
are taken from the literature. Based on nine CCs with a
goodness-of-fit (GOF) statistic smaller than 8 and with an accurate
non-Gaia parallax (σπ comparable to that in GDR2), a
parallax zero-point offset of -0.049±0.018mas is derived. Selecting
a GOF statistic smaller than 8 removes about 40% of the sample most
likely related due to binarity. Excluding first overtone and
multi-mode cepheids and applying some other criteria reduces the
sample to about 200 stars.
The derived PL(Z) relations depend strongly on the parallax zero-point
offset. The slope of the PL relation is found to be different from the
relations in the LMC at the 3σ level. Fixing the slope to the
value found in the LMC leads to a distance modulus (DM) to the LMC of
order 18.7mag, larger than the canonical distance. The canonical DM
of around 18.5 mag would require a parallax zero-point offset of order
-0.1mas. Given the strong correlation between zero point, period
and metallicity dependence of the PL relation, and the parallax
zero-point offset there is no evidence for a metallicity term in the
PLZ relation.
The GDR2 release does not allow us to improve on the current distance
scale based on CCs. The value of and the uncertainty on the parallax
zero-point offset leads to uncertainties of order 0.15mag on the
distance scale. The parallax zero-point offset will need to be known
at a level of 3µas or better to have a 0.01mag or smaller effect on
the zero point of the PL relation and the DM to the LMC.
Description:
The sample of stars is given, with their properties.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 116 452 Sample of stars
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-2014)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name Variable star name (1)
17- 24 A8 --- Type Classification of the variability (2)
25 A1 --- n_Type [+] Note on Type (3)
27- 32 F6.3 d Period Pulsation period, taken from the VSX catalog
(Watson et al., 2006, Cat. B/vsx)
34- 39 F6.3 mag Vmag V-band magnitude
41 I1 --- r_Vmag Reference for V magnitude (4)
45- 50 F6.3 mag Jmag J-band magnitude
52- 57 F6.3 mag Hmag H-band magnitude
59- 64 F6.3 mag Kmag K-band magnitude
66- 72 A7 --- r_Jmag Reference for JHK magnitudes (5)
74- 76 A3 --- Qual In case of single-epoch 2MASS data the
quality-flag is listed if it is not AAA
78 A1 --- o_Kmag ? Available number of K magnitudes if multiple
singe-epoch data was used to obtain the
median magnitude (6)
80- 84 F5.3 mag E(B-V) Colour excess (some corrections have been
applied, see main text)
86- 90 F5.3 mag e_E(B-V) rms uncertainty on colour excess
92 I1 --- r_E(B-V) Reference for E(B-V) (7)
94- 98 F5.2 [-] [Fe/H]1 ? Iron abundance
100 I1 --- r_[Fe/H]1 ? Reference for [Fe/H]1 (8)
102-106 F5.2 [-] [Fe/H]2 ? Iron abundance
108 I1 --- r_[Fe/H]2 ? Reference for [Fe/H]2 (8)
110-114 F5.2 [-] [Fe/H]3 ? Iron abundance
116 I1 --- r_[Fe/H]3 ? Reference for [Fe/H]3 (8)
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Note (1): The last three objects refer to, respectively
ASAS J181024-2049.6, ASAS J171305-4323.0, and
ASAS J184443-0401.5 (or BD -04 4569).
Note (2): The classification of the variability is discussed in the main text,
mainly from the VSX catalog Watson06. See the main text for discussion.
An "?" is added when there are different classifications in the literature.
Note (3): Based on the analysis some classifications are changed, see main text.
These stars are marked by a +.
Note (4): V-band magnitude reference as follows:
1 = Mel'nik et al., 2015, Cat. J/AN/336/70
2 = Berdnikov et al., 20002, Cat. J/A+AS/143/211
3 = Moffett & Barnes (1985ApJS...58..843M 1985ApJS...58..843M)
4 = Groenewegen, 2013, Cat. J/A+A/550/A70
5 = Martin et al., 2015MNRAS.449.4071M 2015MNRAS.449.4071M
6 = mean magnitudes derived in the present paper from data in
Berdnikov, 2008, Cat. II/285 (for V1359 Aql, BC Aql, FQ Lac, QQ Per,
SU Sct, and V526 Aql), the Optical Monitor Camera (OMC) onboard INTEGRAL
OMC2003 https://sdc.cab.inta-csic.es/omc/secure/form_busqueda.jsp
(V1048 Cen, V556 Cas, V1019 Cas, and V411 Lac), and
Garcia-Melendo (2001Ap&SS.275..479G 2001Ap&SS.275..479G) for LO Cam.
7 = APASS (AAVSO Photometric All Sky Survey, Henden et a., 2016, Cat. II/336)
with correction of -0.03mag applied.
Note (5): JHK-band magnitude references as follows:
1 = Monson & Pierce, 2011, Cat. J/ApJS/193/12, intensity-mean magnitude in
the original photometric system
2 = Laney & Stobie, Laney & Stobie, intensity-mean magnitude in
the original photometric system
3 = Laney (priv. comm.) as quoted in Genovali et al., 2014,
Cat. J/A+A/566/A37, intensity-mean magnitude in the original
photometric system
4 = Feast et al., 2008, Cat. J/MNRAS/386/2115, intensity-mean magnitude in
the original photometric system
5 = Barnes et al., 1997PASP..109..645B 1997PASP..109..645B, intensity-mean magnitude in the
original photometric system
6 = Welch et al., 1984ApJS...54..547W 1984ApJS...54..547W, intensity-mean magnitude in the
original photometric system
7 = Genovali et al., 2014, Cat. J/A+A/566/A37, based on single-epoch 2MASS
data and template fitting
8 = Schechter et al., 1992AJ....104.1930S 1992AJ....104.1930S
9 = McGonegal et al., 1983ApJ...269..641M 1983ApJ...269..641M
10 = 2MASS, Cutri et al., 2003, Cat. II/246
11 = DENIS, Cat. B/denis
12 = UKIDSS DR6, Lucas et al., 2012, Cat. II/316
13 = α UMi: COBE-DIRBE flux at 1.25 and 2.2µm converted to 2MASS,
see main text.
Note (6): In that case, the available magnitudes were de-reddened, then
transformed to the 2MASS system, and reddened again. The magnitudes quoted
are thus "observed" magnitudes on the 2MASS system.
Note (7): Reddening value reference as follows:
1 = Fernie et al. (1995IBVS.4148....1F 1995IBVS.4148....1F)
http://www.astro.utoronto.ca/DDO/research/cepheids/table_colourexcess.html
multiplied by 0.94
2 = Acharova et al., 2012, Cat. J/MNRAS/420/1590, without scaling
3 = Luck & Lambert, 2011, Cat. J/AJ/142/136 (scaling by 0.99)
4 = Caldwell & Coulson, 1987AJ.....93.1090C 1987AJ.....93.1090C (scaling by 0.987)
5 = Kashuba et al., 2016, Cat. J/MNRAS/461/839 (scaling by 0.94)
6 = Martin et al., 2015MNRAS.449.4071M 2015MNRAS.449.4071M (scaling by 0.97)
7 = Sziladi et al., 2007A&A...473..579S 2007A&A...473..579S (scaling by 0.92)
8 = based on 3D reddening models (see text)
9 = Andrievsky et al., 2016MNRAS.461.4256A 2016MNRAS.461.4256A, without scaling
Note (8): [Fe/H] references as follows:
1= Genovali et al., 2014, Cat. J/A+A/566/A37
2= Genovali et al., 2015, Cat. J/A+A/580/A17
3= Ngeow, 2012, Cat. J/ApJ/747/50
4= Luck & Lambert, 2011, Cat. J/AJ/142/136
5= Acharova et al., 2012, Cat. J/MNRAS/420/1590, with correction
+0.055dex applied
6= Sziladi et al., 2007A&A...473..579S 2007A&A...473..579S, with correction +0.032dex applied
7= Martin et al., 2015MNRAS.449.4071M 2015MNRAS.449.4071M, with correction +0.030dex applied
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Acknowledgements:
Martin Groenewegen, martin.groenewegen(at)oma.be
(End) Patricia Vannier [CDS] 06-Aug-2018