Search Publications
Derivation of parameters for 3748 FGK stars using H-band spectra from APOGEE Data Release 14
Rojas-Ayala, Bárbara; Delgado Mena, Elisa; Blanco-Cuaresma, Sergi +1 more
Context. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed the H-band spectra of over 200 000 stars with R ∼ 22 000.
Aims: The main motivation for this work is to test an alternative method to the standard APOGEE pipeline (APOGEE Stellar Parameter and Chemical Abundances Pipeline, ASPCAP) to derive parameters in…
No universal connection between the vertical magnetic field and the umbra-penumbra boundary in sunspots
Solanki, S. K.; Lagg, A.; Löptien, B. +1 more
Context. It has been reported that the boundary between the umbra and the penumbra of sunspots occurs at a canonical value of the strength of the vertical magnetic field, independently of the size of the spot. This critical field strength is interpreted to be the threshold for the onset of magnetoconvection.
Aims: Here we investigate the reas…
Physical parameters of selected Gaia mass asteroids
Geier, S.; Pál, A.; Molnár, L. +36 more
Context. Thanks to the Gaia mission, it will be possible to determine the masses of approximately hundreds of large main belt asteroids with very good precision. We currently have diameter estimates for all of them that can be used to compute their volume and hence their density. However, some of those diameters are still based on simple thermal m…
Monitoring clumpy wind accretion in supergiant fast-X-ray transients with XMM-Newton
Romano, P.; Ferrigno, C.; Bozzo, E.
Supergiant fast-X-ray transients (SFXTs) are a sub-class of supergiant high-mass X-ray binaries hosting a neutron star accreting from the stellar wind of a massive OB companion. Compared to the classical systems, SFXTs display a pronounced variability in X-rays that has long been (at least partly) ascribed to the presence of clumps in the stellar …
Correcting the effect of magnetic tongues on the tilt angle of bipolar active regions
López Fuentes, M. C.; Mandrini, C. H.; Démoulin, P. +2 more
Context. The magnetic polarities of bipolar active regions (ARs) exhibit elongations in line-of-sight magnetograms during their emergence. These elongations are referred to as magnetic tongues and attributed to the presence of twist in the emerging magnetic flux-ropes (FRs) that form ARs.
Aims: The presence of magnetic tongues affects the mea…
Extended radio emission associated with a breakout eruption from the back side of the Sun
Palmerio, E.; Kilpua, E. K. J.; Lynch, B. J. +1 more
Context. Coronal mass ejections (CMEs) on the Sun are the largest explosions in the Solar System that can drive powerful plasma shocks. The eruptions, shocks, and other processes associated to CMEs are efficient particle accelerators and the accelerated electrons in particular can produce radio bursts through the plasma emission mechanism.
Ai…
KIC 8975515: A fast-rotating (γ Dor - δ Sct) hybrid star with Rossby modes and a slower δ Sct companion in a long-period orbit
Jofré, P.; Lampens, P.; Samadi-Ghadim, A. +1 more
Aims: KIC 8975515 is a double-lined spectroscopic binary system with hybrid nature. Regular monitoring with the échelle spectrograph HERMES show that both components have matching atmospheric properties (Teff ∼ 7400 K), and that one of them is a fast rotator (v sin i = 162 versus 32 km s-1). Our aim is to study the Keple…
The young stellar content of the giant H II regions M 8, G333.6-0.2, and NGC 6357 with VLT/KMOS
Henning, T.; Kaper, L.; De Ridder, J. +14 more
Context. The identification and characterisation of populations of young massive stars in (giant) H II regions provides important constraints on (i) the formation process of massive stars and their early feedback on the environment, and (ii) the initial conditions for population synthesis models predicting the evolution of ensembles of stars.
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Successful application of PSF-R techniques to the case of the globular cluster NGC 6121 (M 4)
Massari, D.; Fiorentino, G.; Milli, J. +4 more
Context. Precise photometric and astrometric measurements on astronomical images require an accurate knowledge of the point spread function (PSF). When the PSF cannot be modelled directly from the image, PSF-reconstruction techniques become the only viable solution. So far, however, their performance on real observations has rarely been quantified…
Molecular gas in the central region of NGC 7213
Pozzi, F.; Hatziminaoglou, E.; Vignali, C. +4 more
We present a multi-wavelength study (from X-ray to mm) of the nearby low-luminosity active galactic nucleus NGC 7213. We combine the information from the different bands to characterise the source in terms of contribution from the AGN and the host-galaxy interstellar medium. This approach allows us to provide a coherent picture of the role of the …