Search Publications
A celestial matryoshka: dynamical and spectroscopic analysis of the Albireo system
Drimmel, Ronald; Bastian, Ulrich; Sozzetti, Alessandro +4 more
We present a spectroscopic characterization and a new orbital solution for the binary system β Cyg Aa/Ac (MCA 55), the primary component ( β Cyg A) of the well-known wide double star Albireo. By matching evolutionary tracks to the physical parameters of all three Albireo stars ( β Cyg Aa, Ac, and B) as obtained from a spectroscopic analysis of TIG…
MUSE narrow field mode observations of the central kinematics of M15
Dalessandro, Emanuele; Kamann, Sebastian; Sollima, Antonio +4 more
We present observations of the stellar kinematics of the centre of the core collapsed globular cluster M15 obtained with the MUSE integral field spectrograph on the Very Large Telescope operating in narrow field mode. Thanks to the use of adaptive optics, we obtain a spatial resolution of 0.1 arcsec and are able to reliably measure the radial velo…
Pairs of giant shock waves (N-waves) in merging galaxy clusters
Churazov, Eugene; Zhuravleva, Irina; Zhang, Congyao
When a subcluster merges with a larger galaxy cluster, a bow shock is driven ahead of the subcluster. At a later merger stage, this bow shock separates from the subcluster, becoming a 'runaway' shock that propagates down the steep density gradient through the cluster outskirts and approximately maintains its strength and the Mach number. Such shoc…
Data reduction and calibration accuracy of the imaging Fourier transform spectrometer SITELLE
Prunet, S.; Drissen, L.; Martin, T.
SITELLE, an imaging Fourier Transform Spectrometer, is part of the Canada-France-Hawaii instrument suite. It delivers spectral cubes covering an 11 arcmin × 11 arcmin field of view with a seeing-limited spatial resolution and a tunable spectral resolution (R ~ 1-10 000) in selected bands of the visible range (350-900 nm). We present a complete pic…
Dynamically produced moving groups in interacting simulations
Craig, Peter; Chakrabarti, Sukanya; Quillen, Alice +1 more
We show that smoothed particle hydrodynamics (SPH) simulations of dwarf galaxies interacting with a Milky Way-like disc produce moving groups in the simulated stellar disc. We analyse three different simulations: one that includes dwarf galaxies that mimic the Large Magellanic Cloud, Small Magellanic Cloud, and the Sagittarius dwarf spheroidal; an…
Application of a new X-ray reflection model to V1223 Sagittarii
Ishida, Manabu; Hayashi, Takayuki; Kitaguchi, Takao
In intermediate polars (IPs), the intrinsic thermal emissions from white dwarfs (WDs) have typically been studied. Few reports have analysed X-ray reflections from WDs. We recently developed an elaborate IP-reflection spectral model. Herein, we report the first application of a reflection model with an IP thermal model to the spectra of the bright…
Updated values of solar gravitational moments J2n using HMI helioseismic inference of internal rotation
Meftah, M.; Mecheri, R.
The solar gravitational moments J2n are important astronomical quantities whose precise determination is relevant for solar physics, gravitational theory and high precision astrometry, and celestial mechanics. Accordingly, we propose in the present work to calculate new values of J2n (for n = 1, 2, 3, 4, and 5) using recent t…
BAT99-9 - a WC4 Wolf-Rayet star with nitrogen emission: evidence for binary evolution?
Aadland, Erin; Massey, Philip; Hillier, D. John +1 more
An analysis of the Large Magellanic Cloud (LMC) WC4 star BAT99-9 (HD 32125, FD 4, Brey 7, WS 3) shows that the star still contains photospheric nitrogen. Three N emission features (N V λλ1238, 1242, N IV λ1719, and N IV λλ3479-3485) are unambiguously identified in the spectrum. CMFGEN models of the star yield an N/C ratio of 0.004 ± 0.002 (by numb…
Neutral-neutral synthesis of organic molecules in cometary comae
Charnley, S. B.; Cordiner, M. A.
Remote and in situ observations of cometary gases have revealed the presence of a wealth of complex organic molecules, including carbon chains, alcohols, imines, and the amino acid glycine. Such chemical complexity in cometary material implies that impacts by comets could have supplied reagents for prebiotic chemistry to young planetary surfaces. …
Orbital parameters of the hierarchical triplet system CN Lyn
Liao, WenPing; Qian, ShengBang; Li, LinJia
CN Lyn is an intriguing triplet system that contains three equal-mass components. However, the orbital parameters of this rare triple system are still unknown. By monitoring the system since 2016 October 19, 13 eclipse times have been obtained. We discover that the observed minus calculated (O - C) diagram of CN Lyn shows a cyclical variation with…