scholarly journals Standard Galactic field RR Lyrae II: a Gaia DR2 calibration of the period–Wesenheit–metallicity relation

2019 ◽  
Vol 490 (3) ◽  
pp. 4254-4270 ◽  
Author(s):  
Jillian R Neeley ◽  
Massimo Marengo ◽  
Wendy L Freedman ◽  
Barry F Madore ◽  
Rachael L Beaton ◽  
...  

ABSTRACT RR Lyrae stars have long been popular standard candles, but significant advances in methodology and technology have been made in recent years to increase their precision as distance indicators. We present multiwavelength (optical UBVRcIc and Gaia G, BP, RP; near-infrared JHKs; mid-infrared [3.6], [4.5]) period–luminosity–metallicity (PLZ), period–Wesenheit–metallicity (PWZ) relations, calibrated using photometry obtained from the Carnegie RR Lyrae Program and parallaxes from the Gaia second data release for 55 Galactic field RR Lyrae stars. The metallicity slope, which has long been predicted by theoretical relations, can now be measured in all passbands. The scatter in the PLZ relations is on the order of 0.2 mag, and is still dominated by uncertainties in the parallaxes. As a consistency check of our PLZ relations, we also measure the distance modulus to the globular cluster M4, the Large Magellanic Cloud and the Small Magellanic Cloud, and our results are in excellent agreement with estimates from previous studies.

2004 ◽  
Vol 193 ◽  
pp. 189-192
Author(s):  
M. Dall’Ora ◽  
G. Bono ◽  
J. Storm ◽  
V. Ripepi ◽  
V. Testa ◽  
...  

AbstractWe present U, B, V, I (SUSI@NTT) and J,Ks (SOFI@NTT) photometry of the Large Magellanic Cloud (LMC) cluster Reticulum. The observing strategy and data reduction (DAOPHOTII/ALLFRAME) allowed us to reach an accuracy of the order of 0.01 – 0.03 mag in all the bands at limiting magnitudes typical of RR Lyrae stars. Reticulum hosts a sizable sample of RR Lyrae stars (32), and we supply an accurate distance estimate using the RR Lyrae K-band Period-Luminosity-Metallicity (PLZK) relation. This method presents several advantages when compared with the MV vs [Fe/H] relation, since it is only marginally affected by off-ZAHB evolutionary effects and reddening corrections.


2000 ◽  
Vol 176 ◽  
pp. 203-207
Author(s):  
Piotr Popowski

AbstractI demonstrate that the two unexpected results in the local Universe: anomalous intrinsic (V – I)0 colors of RR Lyrae stars and clump giants in the Galactic center, and very short distances to Magellanic Clouds inferred from clump giants, can be at least partially resolved with a modified coefficient of selective extinction AV/E(V – I). With this modification, I find a new clump-giant distance modulus to the Large Magellanic Cloud, μLMC = 18.27 ± 0.07, which is 0.09 larger than the Udalski (1998b) result. When distance estimates from the red clump, RR Lyrae stars and the eclipsing binary HV2274 are combined, one obtains μLMC = 18.31 ± 0.04 (internal).


2003 ◽  
Vol 598 (1) ◽  
pp. 597-609 ◽  
Author(s):  
C. Alcock ◽  
D. R. Alves ◽  
A. Becker ◽  
D. Bennett ◽  
K. H. Cook ◽  
...  

2000 ◽  
Vol 176 ◽  
pp. 172-175 ◽  
Author(s):  
G. Clementini ◽  
A. Bragaglia ◽  
L. Di Fabrizio ◽  
E. Carretta ◽  
R. G. Gratton

AbstractThe Large Magellanic Cloud (LMC) is widely considered a corner-stone of the astronomical distance scale. However, a difference of 0.2−0.3 mag exists in its distance as predicted by the short and long distance scales. Distances to the LMC from Population II objects are founded on the RR Lyrae variables. We have undertaken an observational campaign devoted to the definition of the average apparent luminosity, and to the study of the mass–metallicity relation for RR Lyrae stars in the bar of the LMC. These are compared with analogous quantities for cluster RR Lyrae stars. The purpose is to see whether an intrinsic difference in luminosity, possibly due to a difference in mass, might exist between field and cluster RR Lyrae stars, which could be responsible for the well-known dichotomy between short and long distance scales. Preliminary results are presented on the V and B − V light curves, the average apparent visual magnitude, and the pulsational properties of 102 RR Lyrae stars in the bar of the LMC, observed at ESO in January 1999. The photometric data are accurately tied to the Johnson photometric system. Comparison is presented with the photometry of RR Lyrae stars in the bar of the LMC obtained by the MACHO collaboration (Alcock et al. 1996). Our sample includes 9 double-mode RR Lyrae stars selected from Alcock et al. (1997) for which an estimate of the metal abundance from the ΔS method is presented.


2009 ◽  
Vol 502 (2) ◽  
pp. 505-514 ◽  
Author(s):  
J. Borissova ◽  
M. Rejkuba ◽  
D. Minniti ◽  
M. Catelan ◽  
V. D. Ivanov

2012 ◽  
Vol 8 (S289) ◽  
pp. 116-125 ◽  
Author(s):  
G. Bono ◽  
L. Inno ◽  
N. Matsunaga ◽  
K. Genovali ◽  
B. Lemasle ◽  
...  

AbstractWe present new and independent estimates of the distances to the Magellanic Clouds (MCs) using near-infrared (NIR) and optical–NIR period–Wesenheit (PW) relations. The slopes of the PW relations are, within the dispersion, linear over the entire period range and independent of metal content. The absolute zero points were fixed using Galactic Cepheids with distances based on the infrared surface-brightness method. The true distance modulus we found for the Large Magellanic Cloud—(m − M)0 = 18.48 ± 0.01 ± 0.10 mag—and the Small Magellanic Cloud—(m − M)0 = 18.94 ± 0.01 ± 0.10 mag—agree quite well with similar distance determinations based on robust distance indicators. We also briefly discuss the evolutionary and pulsation properties of MC Cepheids.


2021 ◽  
Vol 922 (1) ◽  
pp. 20
Author(s):  
Anupam Bhardwaj ◽  
Marina Rejkuba ◽  
G. C. Sloan ◽  
Marcella Marconi ◽  
Soung-Chul Yang

Abstract Messier 15 (NGC 7078) is an old and metal-poor post core-collapse globular cluster that hosts a rich population of variable stars. We report new optical (gi) and near-infrared (NIR, JK s ) multi-epoch observations for 129 RR Lyrae, 4 Population II Cepheids (3 BL Herculis, 1 W Virginis), and 1 anomalous Cepheid variable candidate in M15 obtained using the MegaCam and the WIRCam instruments on the 3.6 m Canada–France–Hawaii Telescope. Multi-band data are used to improve the periods and classification of variable stars, and determine accurate mean magnitudes and pulsational amplitudes from the light curves fitted with optical and NIR templates. We derive optical and NIR period–luminosity relations for RR Lyrae stars which are best constrained in the K s band, m K s = − 2.333 ( 0.054 ) log P + 13.948 ( 0.015 ) with a scatter of only 0.037 mag. Theoretical and empirical calibrations of RR Lyrae period–luminosity–metallicity relations are used to derive a true distance modulus to M15: 15.196 ± 0.026 (statistical) ± 0.039 (systematic) mag. Our precise distance moduli based on RR Lyrae stars and Population II Cepheid variables are mutually consistent and agree with recent distance measurements in the literature based on Gaia parallaxes and other independent methods.


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