Search Publications
Orbital inclination and mass of the exoplanet candidate Proxima c
Kervella, Pierre; Arenou, Frédéric; Schneider, Jean
We analyze the orbital parameters of the recently discovered exoplanet candidate Proxima c using a combination of its spectroscopic orbital parameters and Gaia DR2 astrometric proper motion anomaly. We obtain an orbital inclination of i = 152 ± 14 deg, corresponding to a planet mass of mc = 12-5+12 M⊕, c…
Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations. Discussion of recent studies
Mann, G.; Warmuth, A.
Context. In solar flares, energy is released impulsively and is partly converted into thermal energy of hot plasmas and kinetic energy of accelerated nonthermal particles. It is crucial to constrain the partition of these two energy components to understand energy release and transport as well as particle acceleration in solar flares. Despite nume…
An X-ray activity cycle on the young solar-like star ɛ Eridani
Ducci, L.; Wolter, U.; Orlando, S. +7 more
Chromospheric Ca II activity cycles are frequently found in late-type stars, but no systematic programs have been created to search for their coronal X-ray counterparts. The typical time scale of Ca II activity cycles ranges from years to decades. Therefore, long-lasting missions are needed to detect the coronal counterparts. The XMM-Newton satell…
NOEMA redshift measurements of bright Herschel galaxies
Berta, S.; Omont, A.; Lagache, G. +31 more
Using the IRAM NOrthern Extended Millimeter Array (NOEMA), we conducted a program to measure redshifts for 13 bright galaxies detected in the Herschel Astrophysical Large Area Survey with S500 µm ≥ 80 mJy. We report reliable spectroscopic redshifts for 12 individual sources, which are derived from scans of the 3 and 2 mm bands, co…
NuSTAR/XMM-Newton monitoring of the Seyfert 1 galaxy HE 1143-1810. Testing the two-corona scenario
Bianchi, S.; Cappi, M.; Ponti, G. +11 more
Aims: We test the two-corona accretion scenario for active galactic nuclei in the case of the "bare" Seyfert 1 galaxy HE 1143-1810.
Methods: We perform a detailed study of the broad-band UV-X-ray spectral properties and of the short-term variability of HE 1143-1810. We present results of a joint XMM-Newton and NuSTAR monitoring of the so…
The Fornax 3D project: Non-linear colour-metallicity relation of globular clusters
Viaene, S.; Hilker, M.; Pinna, F. +15 more
Globular cluster (GC) systems of massive galaxies often show a bimodal colour distribution. This has been interpreted as a metallicity bimodality, created by a two-stage galaxy formation where the red, metal-rich GCs were formed in the parent halo and the blue metal-poor GCs were accreted. This interpretation, however, crucially depends on the ass…
First direct observation of a torsional Alfvén oscillation at coronal heights
Kohutova, P.; Verwichte, E.; Froment, C.
Context. Torsional Alfvén waves are promising candidates for the transport of energy across different layers of the solar atmosphere. They have been predicted theoretically for decades. Previous detections of Alfvén waves so far have however mostly relied on indirect signatures.
Aims: We present the first direct observational evidence of a fu…
Web of the giant: Spectroscopic confirmation of a large-scale structure around the z = 6.31 quasar SDSS J1030+0524
Comastri, Andrea; Zamorani, Giovanni; Vito, Fabio +14 more
We report on the spectroscopic confirmation of a large-scale structure around the luminous z = 6.31 quasi-stellar object (QSO) SDSS J1030+0524, powered by a one billion solar mass black hole. The structure is populated by at least six members, namely, four Lyman-break galaxies (LBGs), and two Lyman alpha emitters (LAEs). The four LBGs were identif…
Fundamental stellar parameters of benchmark stars from CHARA interferometry. I. Metal-poor stars
White, T. R.; Casagrande, L.; Jofré, P. +4 more
Context. Benchmark stars are crucial as validating standards for current as well as future large stellar surveys of the Milky Way. However, the number of suitable metal-poor benchmark stars is currently limited, owing to the difficulty in determining reliable effective temperatures (Teff) in this regime.
Aims: We aim to construct a…
[C II] 158 µm self-absorption and optical depth effects
Beuther, H.; Stutzki, J.; Güsten, R. +7 more
Context. The [C II] 158 µm far-infrared fine-structure line is one of the most important cooling lines of the star-forming interstellar medium (ISM). It is used as a tracer of star formation efficiency in external galaxies and to study feedback effects in parental clouds. High spectral resolution observations have shown complex structures in…