Search Publications
3D core kinematics of NGC 6362: central rotation in a dynamically evolved globular cluster
Vesperini, Enrico; Dalessandro, Emanuele; Kamann, Sebastian +4 more
We present a detailed 3D kinematic analysis of the central regions (R < 30 arcsec) of the low mass and dynamically evolved galactic globular cluster (GC) NGC 6362. The study is based on data obtained with ESO-VLT/MUSE used in combination with the adaptive optics module and providing ~3000 line-of-sight radial velocities, which have been complem…
D/H in the refractory organics of comet 67P/Churyumov-Gerasimenko measured by Rosetta/COSIMA
Hilchenbach, M.; Merouane, S.; Engrand, C. +11 more
The D/H ratio is a clue to the origin and evolution of hydrogen-bearing chemical species in Solar system materials. D/H has been observed in the coma of many comets, but most such measurements have been for gaseous water. We present the first in situ measurements of the D/H ratios in the organic refractory component of cometary dust particles coll…
The substructure of the Perseus star-forming region: a survey with Gaia DR2
Scholz, Aleks; Teixeira, Paula S.; Pavlidou, Tatiana
We use photometric and kinematic data from Gaia DR2 to explore the structure of the star-forming region associated with the molecular cloud of Perseus. Apart from the two well-known clusters, IC 348 and NGC 1333, we present five new clustered groups of young stars, which contain between 30 and 300 members, named Autochthe, Alcaeus, Heleus, Electry…
The PAU Survey: narrow-band photometric redshifts using Gaussian processes
Alarcon, Alex; Carretero, Jorge; Castander, Francisco J. +16 more
We study the performance of the hybrid template machine learning photometric redshift (photo-z) algorithm DELIGHT, which uses Gaussian processes, on a subset of the early data release of the Physics of the Accelerating Universe Survey (PAUS). We calibrate the fluxes of the 40 PAUS narrow bands with six broad-band fluxes (uBVriz) in the Cosmic Evol…
Metallicities from high-resolution spectra of 49 RR Lyrae variables
Dall'Ora, Massimo; Bono, Giuseppe; Fiorentino, Giuliana +12 more
Accurate metallicities of RR Lyrae are extremely important in constraining period-luminosity-metallicity (PLZ) relationships, particularly in the near-infrared. We analyse 69 high-resolution spectra of Galactic RR Lyrae stars from the Southern African Large Telescope. We measure metallicities of 58 of these RR Lyrae stars with typical uncertaintie…
Characterization of 92 southern TESS candidate planet hosts and a new photometric [Fe/H] relation for cool dwarfs
Nordlander, Thomas; Casagrande, Luca; Žerjal, Maruša +7 more
We present the results of a medium-resolution optical spectroscopic survey of 92 cool ($3000 \,\mathrm{ K}\lesssim T_{\rm eff} \lesssim 4500\,$K) southern TESS candidate planet hosts, and describe our spectral fitting methodology used to recover stellar parameters. We quantify model deficiencies at predicting optical fluxes, and while our techniqu…
Constraining the shear acceleration model for the X-ray emission of large-scale extragalactic jets
Tavecchio, F.
The nature of the intense X-ray emission from powerful extragalactic jets at large (>1 kpc) scale is still debated. The scenario that invokes the inverse Compton scattering of the cosmic microwave background by electrons is challenged by the lack of gamma-ray emission in the GeV band. An alternative assumes synchrotron emission by a distinct po…
A transit timing variation observed for the long-period extremely low-density exoplanet HIP 41378 f
Triaud, Amaury H. M. J.; Wheatley, Peter J.; Bayliss, Daniel +47 more
HIP 41378 f is a temperate 9.2 ± 0.1 R⊕ planet with period of 542.08 d and an extremely low density of 0.09 ± 0.02 g cm-3. It transits the bright star HIP 41378 (V = 8.93), making it an exciting target for atmospheric characterization including transmission spectroscopy. HIP 41378 was monitored photometrically between the dat…
Search for globular clusters associated with the Milky Way dwarf galaxies using Gaia DR2
Koposov, Sergey E.; Huang, Kuan-Wei
We report the result of searching for globular clusters (GCs) around 55 Milky Way (MW) satellite dwarf galaxies within the distance of 450 kpc from the Galactic Centre except for the Large and Small Magellanic Clouds and the Sagittarius dwarf. For each dwarf, we analyse the stellar distribution of sources in Gaia DR2, selected by magnitude, proper…
Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations
Verscharen, Daniel; Velli, Marco; Bale, Stuart D.
One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfvénic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the Sun into interplanetary space. We present a framework based on two-fluid magnetohydrodynamics to estimate the flu…