In a framework where galaxies form hierarchically, extended stellar haloes are predicted to be an ubiquitous feature around Milky Way-like galaxies and to consist mainly of the shredded stellar component of smaller galactic systems. The type of accreted stellar systems are expected to vary according to the specific accretion and merging history of
What is the Milky Way outer halo made of?. High resolution spectroscopy of distant red giantsBattaglia, G. et al.122017
What Is the Redshift of the Gamma-ray BL Lac Source S4 0954+65?
High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by the MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in 2015 February, making the determination of its distance particularly relevantLandoni, M. et al.
Wide-field Precision Kinematics of the M87 Globular Cluster System
We present the most extensive combined photometric and spectroscopic study to date of the enormous globular cluster (GC) system around M87, the central giant elliptical galaxy in the nearby Virgo Cluster. Using observations from DEIMOS and the Low Resolution Imaging Spectrometer at Keck, and Hectospec on the Multiple Mirror Telescope, we derive newStrader, Jay et al.
Widely separated binary systems of very low-mass stars
In this paper we review some recent detections of wide binary brown dwarf systems and discuss them in the context of the multiplicity properties of very low-mass stars and brown dwarfs.Phan-Bao, N. et al.
Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1
The black hole binary, Cyg X-1, is generally observed in one of two long duration X-ray states: a low flux, hard spectrum state (most common) and a high flux, soft spectrum state (rare). Models predict that the high/ soft state corresponds to a high mass transfer phase in the binary, and since the X-ray source is fueled by accretion from theGies, D. R. et al.
Wind variability of LBV stars
General properties of Luminous Blue Variables (LBV) have been reviewed by Lamers (1987). The LBV's are all close to the Humphreys-Davidson luminosity upper limit. The semi periods of the photometric microvariations with Delta V is about 0.1m are about twice as large as for normal supergiants of the same L and Teff, and 4-20 times larger than theIsraelian, G. L.