J/MNRAS/481/1195 Gaia DR2 RR Lyrae stars as standard candles (Muraveva+, 2018)
RR Lyrae stars as standard candles in the Gaia Data Release 2 Era.
Muraveva T., Delgado H.E., Clementini G., Sarro L.M., Garofalo A.
<Mon. Not. R. Astron. Soc., 481, 1195-1211 (2018)>
=2018MNRAS.481.1195M 2018MNRAS.481.1195M (SIMBAD/NED BibCode)
ADC_Keywords: Parallaxes, trigonometric ; Stars, variable ; Magellanic Clouds
Keywords: parallaxes - stars: variables: RR Lyrae -
galaxies: distances and redshifts - Magellanic Clouds
Abstract:
We present results from the analysis of 401 RR Lyrae stars (RRLs)
belonging to the field of the Milky Way (MW). For a fraction of them
multiband (V, Ks, W1) photometry, metal abundances, extinction values,
and pulsation periods are available in the literature and accurate
trigonometric parallaxes measured by the Gaia mission alongside Gaia
G-band time-series photometry have become available with the Gaia Data
Release 2 (DR2) on 2018 April 25. Using a Bayesian fitting approach,
we derive new near-, mid-infrared period-absolute
magnitude-metallicity (PMZ) relations and new absolute
magnitude-metallicity relations in the visual (MV-[Fe/H]) and G
bands (MG-[Fe/H]), based on the Gaia DR2 parallaxes. We find the
dependence of luminosity on metallicity to be higher than usually
found in the literature, irrespective of the passband considered.
Running the adopted Bayesian model on a simulated data set we show
that the high-metallicity dependence is not caused by the method, but
likely arises from the actual distribution of the data and the
presence of a zero-point offset in the Gaia parallaxes. We infer a
zero-point offset of -0.057 mas, with the Gaia DR2 parallaxes being
systematically smaller. We find the RR Lyrae absolute magnitude in the
V, G, Ks, and W1 bands at metallicity of [Fe/H]=-1.5dex and period of
P=0.5238d, based on Gaia DR2 parallaxes to be MV=0.66±0.06mag,
MG=0.63±0.08mag, MKs=-0.37±0.11mag, and
MW1=-0.41±0.11mag, respectively.
Description:
Following Gaia Collaboration et al. (2017A&A...605A..79G 2017A&A...605A..79G, Cat.
J/A+A/605/A79), we select a sample of 403 MW field RRLs studied by
Dambis et al. (2013MNRAS.435.3206D 2013MNRAS.435.3206D, Cat. J/MNRAS/435/3206), who have
collected and homogenized literature values of period, pulsation mode,
extinction in the visual passband (AV), metal abundance ([Fe/H]),
and intensity-averaged magnitudes in the Johnson V, 2MASS Ks, and
WISE W1 passbands. Of the 403 RRLs Dambis et al., we discarded two
objects. BB Vir turned out to be a blend of two stars and the rather
long period of BI Tel (P=1.17d) would place the star in the Anomalous
Cepheid domain. Our final sample consists of 401 RRLs, of which 366
pulsate in the fundamental mode and 35 in the first-overtone mode. We
have cross-matched our catalogue of 401 RRLs against the Gaia DR2
catalogue available through the Gaia Archive web site using a
cross-match radius of 4 arcsec, and recovered the DR2 parallaxes for
all of them. The complete data set, namely identifications,
parallaxes, positions, and mean G magnitudes from the Gaia DR2
catalogue, alongside the period, pulsation mode, extinction, metal
abundance and mean V, Ks, and W1 magnitudes available in the
literature for these 401 RRLs, are provided in Table 1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 153 401 Data set for the 401 RRLs
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/MNRAS/435/3206 : Catalog of parameters of Galactic RR Lyrae variables
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Star Name
11- 29 I19 --- GaiaDR2 Gaia DR2 source ID
31- 39 F9.5 deg RAdeg Right Ascension (ICRS) at Ep=2015.5 from
Gaia DR2
41- 49 F9.5 deg DEdeg Declination (ICRS) at Ep=2015.5 from Gaia DR2
51- 56 F6.3 mas plx Parallax from GAIA DR2
58- 62 F5.3 mas e_plx Error on plx
64- 65 A2 --- Type RRL type
67 A1 --- f_Type [a] Flag on Type (1)
69- 74 F6.4 d P Period
76 A1 --- f_P [a] Flag on P (1)
78- 83 F6.3 mag Vmag ? Mean V magnitude (2)
85- 89 F5.3 mag e_Vmag ? Error on Vmag
91- 96 F6.3 mag Ksmag Mean Ks magnitude (2)
98-102 F5.3 mag e_Ksmag Error on Ksmag
104 A1 --- f_Ksmag [b] Flag on Ksmag (3)
106-111 F6.3 mag W1mag ? Mean W1 magnitude (2)
113-117 F5.3 mag e_W1mag ? Error on W1mag (4)
119-126 F8.5 mag Gmag ? Mean G magnitude
128-134 F7.5 mag e_Gmag ? Error on Gmag
136-140 F5.2 --- [Fe/H] ? Metallicity on the Zinn & West
(1984ApJS...55...45Z 1984ApJS...55...45Z) metallicity scale
142-145 F4.2 --- e_[Fe/H] ? Error on [Fe/H]
147-151 F5.3 mag Avmag Extinction in the V band
153 A1 --- f_Avmag ? Flag on Avmag (1)
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Note (1): Flag as follows:
a = Parameters were changed according to updated informations
Note (2): Mean V, Ks, and W1 magnitudes from Dambis et al. (2013MNRAS.435.3206D 2013MNRAS.435.3206D)
Note (3): Flag as follows:
b = For the 32 RRLs with singe epoch measurements in the Ks band an
uncertainty for the mean Ks magnitudes of 0.175mag was assumed
Note (4): An additional uncertainty of 0.02mag was added to the uncertainties
in the mean W1 magnitudes presented in the table while running the
model
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 08-Jun-2022