ELSA and the frontiers of astrometry

ELSA stands for the ambitious goal of `European Leadership in Space Astrometry'. In this closing contribution I will examine how the ELSA network has advanced this goal. I also look ahead to the time when the Gaia data will be published and consider what needs to be done to maintain European leadership.Comment: Closing remarks at the ELSA conference "Gaia: at the frontiers of astrometry". Proceedings editors: C. Turon, F. Arenou & F. Meynadie

A catalog of known Galactic K-M stars of class I, candidate RSGs, in Gaia DR2

We investigate individual distances and luminosities of a sample of 889 nearby candidate red supergiants with reliable parallaxes (plx/plxerr > 4 and RUWE < 2.7) from Gaia DR2. The sample was extracted from the historical compilation of spectroscopically derived spectral types by Skiff (2014), and consists of K-M stars that are listed with class I at least once. The sample includes well-known red supergiants from Humphreys (1978), Elias et al. (1985), Jura and Kleinmann (1990), and Levesque et al. (2005). Infrared and optical measurements from the 2MASS, CIO, MSX, WISE, MIPSGAL, GLIMPSE, and NOMAD catalogs allow us to estimate the stellar bolometric magnitudes. We analyze the stars in the luminosity versus effective temperature plane and confirm that 43 sources are highly-probably red supergiants with Mbol<-7.1 mag. 43% of the sample is made of stars with masses > 7 Msun. Another 30% of the sample consists of giant stars.Comment: 14 pages, 7 Figures, accepted by ApJ. See https://somethingaboutrsgstars.wordpress.com/ or http://staff.ustc.edu.cn/~messine

Gaia archive

The Gaia archive is being designed and implemented by the DPAC Consortium. The purpose of the archive is to maximize the scientific exploitation of the Gaia data by the astronomical community. Thus, it is crucial to gather and discuss with the community the features of the Gaia archive as much as possible. It is especially important from the point of view of the GENIUS project to gather the feedback and potential use cases for the archive. This paper presents very briefly the general ideas behind the Gaia archive and presents which tools are already provided to the community.Comment: Proceedings of the XXXVII Meeting of the Polish Astronomical Societ

Simulations of Adaptive Optics with a Laser Guide Star for SINFONI

The SINFONI instrument for ESO's VLT combines integral field spectroscopy and adaptive optics (AO). We discuss detailed simulations of the adaptive optics module. These simulations are aimed at assessing the AO module performance, specifically for operations with extended sources and a laser guide star. Simulated point spread function (PSF) images will be used to support scientific preparations and the development of an exposure time calculator, while simulated wavefront sensor measurements will be used to study PSF reconstruction methods. We explain how the adaptive optics simulations work, focusing on the realistic modelling of the laser guide star for a curvature wavefront sensor. The predicted performance of the AO module is discussed, resulting in recommendations for the operation of the SINFONI AO module at the telescope.Comment: 12 pages, 6 figures, to appear in SPIE conference proceedings vol 5490, "Advancements in Adaptive Optics", eds. D. Bonaccini, B.L. Ellerbroek, R. Ragazonni, Glasgow UK, 21-25 June 200

Simultaneous measurement of multiple parameters of a subwavelength structure based on the weak value formalism

A mathematical extension of the weak value formalism to the simultaneous measurement of multiple parameters is presented in the context of an optical focused vector beam scatterometry experiment. In this example, preselection and postselection are achieved via spatially-varying polarization control, which can be tailored to optimize the sensitivity to parameter variations. Initial experiments for the two-parameter case demonstrate that this method can be used to measure physical parameters with resolutions at least 1000 times smaller than the wavelength of illumination

OB Associations

Since the previous (1990) edition of this meeting enormous progress in the field of OB associations has been made. Data from X-ray satellites have greatly advanced the study of the low-mass stellar content of associations, while astrometric data from the Hipparcos satellite allow for a characterization of the higher-mass content of associations with unprecedented accuracy. We review recent work on the OB associations located within 1.5 kpc from the Sun, discuss the Hipparcos results at length, and point out directions for future research.Comment: To appear in The Physics of Star Formation and Early Stellar Evolution II, eds C.J. Lada & N. Kylafis (Kluwer Academic), 30 pages, 9 EPS-figures, LaTeX using crckapb.sty, epsfig.sty, amssymb.st