Surface brightness control3/10/2023 ![]() ![]() In the course of the Araucaria project ( Gieren et al. 2008), a few dozen extremely scarce long-period eclipsing systems composed of late-type clump giants were cataloged ( Graczyk et al. Late-type eclipsing-binary systems provide the opportunity of measuring accurate distances by combining the linear diameter (derived from the light curve and velocimetry) and angular diameters (derived from a surface-brightness color relation, SBCR) of their components.īased on the observation of some 35 million stars in the LMC for more than 20 yr during the Optical Gravitational Lensing Experiment (OGLE Udalski et al. (2019) achieved a 1.9% precision by relying on the distance to the Large Magellanic Cloud (LMC), which is the best anchor point for the cosmic distance scale ( Schaefer 2008 Walker et al. In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of 2% or better ( Komatsu et al. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. It also indicates that it is possible to combine interferometric observations at different wavelengths when the SBCR is calibrated. The consistency of the infrared and visible angular diameters and SBCR reinforces the result of 1% precision and accuracy recently achieved on the distance of the LMC using the eclipsing-binary technique. The SBCR we obtain in the visible has a dispersion of 0.04 magnitude and is consistent with the one derived in the infrared (0.018 magnitude).Ĭonclusions. For the four stars in common observed by both VEGA/CHARA and PIONIER/VLTI, we find a 1 σ agreement for the angular diameters. The average precision we obtain on the limb-darkened angular diameters of the eight stars in our sample is 2.4%. The derived limb-darkened angular diameters were combined with a homogeneous set of infrared magnitudes in order to constrain the SBCR. Observations of eight G–K giants were obtained with the VEGA/CHARA instrument. ![]() We calibrate the SBCR for red giant stars in the 2.1 ≤ V − K ≤ 2.5 color range using homogeneous VEGA/CHARA interferometric data secured in the visible domain, and compare it to the relation based on infrared interferometric observations, which were used to derive the distance to the LMC. It was for instance used to derive the distance of eclipsing binaries in the Large Magellanic Cloud (LMC), which led to its distance determination with an accuracy of 1%.Īims. The surface brightness – color relationship (SBCR) is a poweful tool for determining the angular diameter of stars from photometry. Université de Lyon, Université Lyon 1, Ecole Normale Supérieure de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon UMR5574,Ĭontext. LESIA (UMR 8109), Observatoire de Paris, PSL, CNRS, UPMC, Univ. Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS UMI 3386), Departamento de Astronomía, Universidad de Chile, Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS,ĭepartamento de Astronomía, Universidad de Concepción, Astronomical objects: linking to databases.Including author names using non-Roman alphabets.Suggested resources for more tips on language editing in the sciences Punctuation and style concerns regarding equations, figures, tables, and footnotes Finally, to orchestrate a controlled analysis, the concept of reproducibility is discussed: this paper itself is exactly reproducible (commit 751467d). For a detailed list of improvements after version 0.10, see the most recent manual. Segment is also able to detect the localized HII regions as "clumps" much more successfully. Another major change is the final growth strategy of its true detections, for example NoiseChisel is able to detect the outer wings of M51 down to S/N of 0.25, or 25.97 mag/arcsec2 on a single-exposure SDSS image (r-band). The most important change until version 0.10 is that NoiseChisel's segmentation features have been moved into a new program called Segment. The 10th stable version of Gnuastro was released in August 2019 and NoiseChisel has significantly improved: detecting even fainter signal, enabling better user control over its inner workings, and many bug fixes. It was introduced in 2015 and released within a collection of data analysis programs and libraries known as GNU Astronomy Utilities (Gnuastro). NoiseChisel is a program to detect very low signal-to-noise ratio (S/N) features with minimal assumptions on their morphology. ![]()
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |