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K2-106, a system containing a metal-rich planet and a planet of lower density
Deeg, H.; Erikson, A.; Fridlund, M. +43 more
Aims: Planets in the mass range from 2 to 15 M⊕ are very diverse. Some of them have low densities, while others are very dense. By measuring the masses and radii, the mean densities, structure, and composition of the planets are constrained. These parameters also give us important information about their formation and evolution, an…
The formation of the Milky Way halo and its dwarf satellites; a NLTE-1D abundance analysis. I. Homogeneous set of atmospheric parameters
Jablonka, P.; North, P.; Sitnova, T. +2 more
We present a homogeneous set of accurate atmospheric parameters for a complete sample of very and extremely metal-poor stars in the dwarf spheroidal galaxies (dSphs) Sculptor, Ursa Minor, Sextans, Fornax, Boötes I, Ursa Major II, and Leo IV. We also deliver a Milky Way (MW) comparison sample of giant stars covering the - 4 < [Fe/H] < - 1.7 m…
SHARP - IV. An apparent flux-ratio anomaly resolved by the edge-on disc in B0712+472
Vegetti, S.; McKean, J. P.; Auger, M. W. +6 more
Flux-ratio anomalies in quasar lenses can be attributed to dark matter substructure surrounding the lensing galaxy and thus used to constrain the substructure mass fraction. Previous applications of this approach infer a substructure abundance that is potentially in tension with the predictions of Λ cold dark matter cosmology. However, the assumpt…
Dominant dark matter and a counter-rotating disc: MUSE view of the low-luminosity S0 galaxy NGC 5102
Cappellari, Michele; Walcher, C. Jakob; Mitzkus, Martin
The kinematics and stellar populations of the low-mass nearby S0 galaxy NGC 5102 are studied from integral field spectra taken with the Multi-Unit Spectroscopic Explorer. The kinematic maps reveal for the first time that NGC 5102 has the characteristic 2σ peaks indicative of galaxies with counter-rotating discs. This interpretation is quantitative…
Evolution of the ion environment of comet 67P during the Rosetta mission as seen by RPC-ICA
Henri, Pierre; Alho, Markku; Simon Wedlund, Cyril +10 more
Rosetta has followed comet 67P from low activity at more than 3.6 au heliocentric distance to high activity at perihelion (1.24 au) and then out again. We provide a general overview of the evolution of the dynamic ion environment using data from the RPC-ICA ion spectrometer. We discuss where Rosetta was located within the evolving comet magnetosph…
Hot gas around SN 1998bw: Inferring the progenitor from its environment
Galbany, L.; Schady, P.; Krühler, T. +3 more
Spatially resolved spectroscopy of the environments of explosive transients carries detailed information about the physical properties of the stellar population that gave rise to the explosion, and thus the progenitor itself. Here, we present new observations of ESO184-G82, the galaxy hosting the archetype of the γ-ray burst/supernova connection, …
CMB constraints on the inflaton couplings and reheating temperature in α-attractor inflation
Drewes, Marco; Kang, Jin U.; Mun, Ui Ri
We study reheating in α-attractor models of inflation in which the inflaton couples to other scalars or fermions. We show that the parameter space contains viable regions in which the inflaton couplings to radiation can be determined from the properties of CMB temperature fluctuations, in particular the spectral index. This may be the only way to …
Lessons from the Auriga discs: the hunt for the Milky Way's ex situ disc is not yet over
Monachesi, Antonela; Springel, Volker; Grand, Robert J. J. +7 more
We characterize the contribution from accreted material to the galactic discs of the Auriga Project, a set of high-resolution magnetohydrodynamic cosmological simulations of late-type galaxies performed with the moving-mesh code AREPO. Our goal is to explore whether a significant accreted (or ex situ) stellar component in the Milky Way disc could …
2WHSP: A multi-frequency selected catalogue of high energy and very high energy γ-ray blazars and blazar candidates
Giommi, P.; Padovani, P.; Chang, Y. -L. +1 more
Aims: High synchrotron peaked blazars (HSPs) dominate the γ-ray sky at energies higher than a few GeV; however, only a few hundred blazars of this type have been cataloged so far. In this paper we present the 2WHSP sample, the largest and most complete list of HSP blazars available to date, which is an expansion of the 1WHSP catalogue of γ-ra…
VLT/FORS2 comparative transmission spectroscopy II: Confirmation of a cloud deck and Rayleigh scattering in WASP-31b, but no potassium?
Nikolov, Nikolay; Gibson, Neale P.; Sing, David K. +4 more
We present transmission spectroscopy of the hot-Jupiter WASP-31b using the FOcal Reducer and low dispersion Spectrograph 2 (FORS2) on the Very Large Telescope during two primary transits. The observations cover a wavelength range of ≈400-840 nm. The light curves are corrupted by significant systematics, but these were to first-order invariant with…