ﻻ يوجد ملخص باللغة العربية
The zero point of the reddening toward the Large Magellanic Cloud (LMC) has been the subject of some dispute. Its uncertainty propagates as a systematic error for methods which measure the extragalactic distance scale through knowledge of the absolute extinction of LMC stars. In an effort to resolve this issue, we used three different methods to calibrate the most widely-used metric to predict LMC extinction, the intrinsic color of the red clump, $(V-I)_{RC,0}$, for the inner $sim$3 degrees of that galaxy. The first approach was to empirically calibrate the color zeropoints of the BaSTI isochrones over a wide metallicity range of ${Delta}rm{[Fe/H]} approx 1.10$ using measurements of red clump stars in 47 Tuc, the Solar Neighborhood, and NGC 6791. From these efforts we also measure these properties of the Solar Neighborhood red clump, ($V-I$, $G_{BP}-K_{s}$, $G-K_{s}$, $G_{RP}-K_{s}$, $J-K_{s}$, $H-K_{s}$, $M_{I}$, $M_{Ks}$)$_{RC,0} =$ (1.02, 2.75, 2.18, 1.52, 0.64, 0.15, $-$0.23, $-$1.63). The second and third methods were to compare the observed colors of the red clump to those of Cepheids and RR Lyrae in the LMC. With these three methods, we estimated the intrinsic color of the red clump of the LMC to be $(V-I)_{RC,0,rm{LMC}} = { approx 0.93,0.91 pm 0.02,0.89 pm 0.02}$ respectively, and similarly using the first and third method we estimated $ (V-I)_{RC,0,rm{SMC}} = {approx 0.85,0.84 pm 0.02 }$ respectively for the Small Magellanic Cloud. We estimate the luminosities to be $M_{I,RC,rm{LMC}}=-0.26$ and $M_{I,RC,rm{SMC}}=-0.37$. We show that this has important implications for recent calibrations of the tip of the red giant branch in the Magellanic Clouds used to measure $H_0$.
We present the most extensive and detailed reddening maps of the Magellanic Clouds (MCs) derived from the color properties of Red Clump (RC) stars. The analysis is based on the deep photometric maps from the fourth phase of the Optical Gravitational
Although core helium-burning red clump (RC) stars are faint at ultraviolet wavelengths, their ultraviolet-optical color is a unique and accessible probe of their physical properties. Using data from the GALEX All Sky Imaging Survey, Gaia Data Release
Red clump (RC) stars are widely used as an excellent standard candle. To make them even better, it is important to know the dependence of their absolute magnitudes on age and metallicity. We observed star clusters in the Large Magellanic Cloud to fil
In this paper JK_s data from the VISTA Magellanic Cloud (VMC) survey are used to investigate the tip of the red giant branch (TRGB) as a distance indicator. A linear fit to recent theoretical models is used which reads M_{K_s} = -4.196 -2.013 (J-K_s)
I review the literature covering the issue of interstellar extinction toward the Milky Way bulge, with emphasis placed on findings from planetary nebulae, RR Lyrae, and red clump stars. I also report on observations from HI gas and globular clusters.