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Period-luminosity diagram of long period variables in the Magellanic Clouds. New aspects revealed from Gaia Data Release 2
Mowlavi, N.; Lecoeur-Taïbi, I.; Lebzelter, T. +4 more
Context. The period-luminosity diagram (PLD) has proven to be a powerful tool for studying populations of pulsating red giants. Gaia Data Release 2 (DR2) provides a large data set including many long-period variables (LPVs) on which this tool can be applied.
Aims: We investigate the location of LPVs from the Large and Small Magellanic Clouds …
HD 101584: circumstellar characteristics and evolutionary status
Lindqvist, M.; Olofsson, H.; Bergman, P. +8 more
Context. There is growing evidence that red giant evolution is often affected by an interplay with a nearby companion, in some cases taking the form of a common-envelope evolution.
Aims: We have performed a study of the characteristics of the circumstellar environment of the binary object HD 101584, that provides information on a likely evolu…
Transit least-squares survey. II. Discovery and validation of 17 new sub- to super-Earth-sized planets in multi-planet systems from K2
Heller, René; Hippke, Michael; Rodenbeck, Kai
The extended Kepler mission (K2) has revealed more than 500 transiting planets in roughly 500 000 stellar light curves. All of these were found either with the box least-squares algorithm or by visual inspection. Here we use our new transit least-squares (TLS) algorithm to search for additional planets around all K2 stars that are currently known …
Systematic investigation of chemical abundances derived using IR spectra obtained with GIANO
Ryde, N.; Ludwig, H. -G.; Bonifacio, P. +11 more
Context. Detailed chemical abundances of Galactic stars are needed in order to improve our knowledge of the formation and evolution of our galaxy, the Milky Way.
Aims: We took advantage of the GIANO archive spectra to select a sample of Galactic disc stars in order to derive their chemical inventory and to compare the abundances we derived fr…
12,660 Spotted Stars toward the OGLE Galactic Bulge Fields
Soszyński, I.; Udalski, A.; Szymański, M. K. +12 more
We present the discovery and statistical analysis of 12,660 spotted variable stars toward and inside the Galactic bulge from the Optical Gravitational Lensing Experiment (OGLE) data that are over two decades long. We devise a new method of dereddening of individual stars toward the Galactic bulge where strong and highly nonuniform extinction is pr…
The Galactic Bulge Diffuse Emission in Broadband X-Rays with NuSTAR
Wik, Daniel R.; Krivonos, Roman; Perez, Kerstin
The diffuse hard X-ray emission that fills the Galactic center, bulge, and ridge is believed to arise from unresolved populations of X-ray binary systems. However, the identity of the dominant class of accreting objects in each region remains unclear. Recent studies of Fe line properties and the low-energy (<10 keV) X-ray continuum of the bulge…
The behaviour of chemical elements in 62 Am star candidates
Giarrusso, M.; Leone, F.; Busà, I. +3 more
In this paper, we present the results of a spectroscopic campaign devoted to ascertain the actual nature of a sample of 155 objects reported as uncertain peculiar stars in the General catalogue of Ap, Am, and HgMn stars. Spectroscopic observations have been obtained with Catania Astrophysical Observatory Spectropolarimeter. We derive for all the o…
New type II Cepheids from VVV data towards the Galactic center
Minniti, D.; Zoccali, M.; Contreras Ramos, R. +5 more
Context. The Galactic center (GC) is the densest region of the Milky Way. Variability surveys towards the GC potentially provide the largest number of variable stars per square degree within the Galaxy. However, high stellar density is also a drawback due to blending. Moreover, the GC is affected by extreme reddening, therefore near infrared obser…
Cooling in the X-ray halo of the rotating, massive early-type galaxy NGC 7049
Simionescu, A.; Gaspari, M.; Sun, M. +9 more
The relative importance of the physical processes shaping the thermodynamics of the hot gas permeating rotating, massive early-type galaxies is expected to be different from that in non-rotating systems. Here, we report the results of the analysis of XMM-Newton data for the massive, lenticular galaxy NGC 7049. The galaxy harbours a dusty disc of c…
The course of the Orphan Stream in the Northern Galactic hemisphere traced with Gaia DR2
van der Marel, Roeland P.; Fardal, Mark A.; Sohn, Sangmo Tony +1 more
The Orphan Stream is one of the most prominent tidal streams in the Galactic halo. Using data on red giants, RR Lyrae, and horizontal branch stars from Gaia and other surveys, we determine the proper motion of the Orphan Stream over a path of more than 90° on the sky. We also provide updated tracks for the sky position, distance, and radial veloci…