Search Publications
A 3D view of the Hyades stellar and sub-stellar population
Smart, R. L.; Lodieu, N.; Pérez-Garrido, A. +1 more
Aims: Our scientific goal is to provide a 3D map of the nearest open cluster to the Sun, the Hyades, combining the recent release of Gaia astrometric data, ground-based parallaxes of sub-stellar member candidates and photometric data from surveys which cover large areas of the cluster.
Methods: We combined the second Gaia release with gr…
Optical polarised phase function of the HR 4796A dust ring
Pinte, C.; Ménard, F.; Avenhaus, H. +23 more
Context. The scattering properties of the dust originating from debris discs are still poorly known. The analysis of scattered light is however a powerful remote-sensing tool to understand the physical properties of dust particles orbiting other stars. Scattered light is indeed widely used to characterise the properties of cometary dust in the sol…
A method for global inversion of multi-resolution solar data
de la Cruz Rodríguez, J.
Understanding the complex dynamics and structure of the upper solar atmosphere strongly benefits from the use of a combination of several diagnostics. Frequently, such diverse diagnostics can only be obtained from telescopes and/or instrumentation operating at widely different spatial resolution. To optimize the utilization of such data, we propos…
Stellar ages, masses, and radii from asteroseismic modeling are robust to systematic errors in spectroscopy
Hekker, S.; Basu, S.; Stokholm, A. +2 more
Context. The search for twins of the Sun and Earth relies on accurate characterization of stellar and the exoplanetary parameters age, mass, and radius. In the modern era of asteroseismology, parameters of solar-like stars are derived by fitting theoretical models to observational data, which include measurements of their oscillation frequencies, …
The missing light of the Hubble Ultra Deep Field
Borlaff, Alejandro; Eliche-Moral, M. Carmen; Beckman, John E. +11 more
Context. The Hubble Ultra Deep field (HUDF) is the deepest region ever observed with the Hubble Space Telescope. With the main objective of unveiling the nature of galaxies up to z ∼ 7 - 8, the observing and reduction strategy have focused on the properties of small and unresolved objects, rather than the outskirts of the largest objects, which ar…
A census of massive stars in NGC 346. Stellar parameters and rotational velocities
Dufton, P. L.; Lennon, D. J.; Evans, C. J. +2 more
Spectroscopy for 247 stars towards the young cluster NGC 346 in the Small Magellanic Cloud has been combined with that for 116 targets from the VLT-FLAMES Survey of Massive Stars. Spectral classification yields a sample of 47 O-type and 287 B-type spectra, while radial-velocity variations and/or spectral multiplicity have been used to identify 45 …
HST spectra reveal accretion in MY Lupi
France, K.; Alcalá, J. M.; Manara, C. F. +5 more
The mass accretion rate is a crucial parameter for the study of the evolution of accretion discs around young low-mass stellar and substellar objects (YSOs). We revisit the case of MY Lup, an object where VLT/X-shooter data suggested a negligible mass accretion rate, and show it to be accreting on a level similar to other Class II YSOs in Lupus ba…
Multiphase quasar-driven outflows in PG 1114+445. I. Entrained ultra-fast outflows
Piconcelli, Enrico; Tombesi, Francesco; Serafinelli, Roberto +3 more
Substantial evidence in the last few decades suggests that outflows from supermassive black holes (SMBH) may play a significant role in the evolution of galaxies. These outflows, powered by active galactic nuclei (AGN), are thought to be the fundamental mechanism by which the SMBH transfers a significant fraction of its accretion energy to the sur…
The most luminous blue quasars at 3.0 < z < 3.3. I. A tale of two X-ray populations
Marconi, A.; Vignali, C.; Gilli, R. +8 more
We present the X-ray analysis of 30 luminous quasars at z ≃ 3.0 - 3.3 with pointed XMM-Newton observations (28-48 ks) originally obtained by our group to test the suitability of active galactic nuclei as standard candles for cosmological studies. The sample was selected in the optical from the Sloan Digital Sky Survey Data Release 7 to be represen…
Massive galaxies on the road to quenching: ALMA observations of powerful high redshift radio galaxies
Lehnert, Matthew D.; De Breuck, Carlos; Wylezalek, Dominika +10 more
We present 0.″3 (band 6) and 1.″5 (band 3) ALMA observations of the (sub)millimeter dust continuum emission for 25 radio galaxies at 1 < z < 5.2. Our survey reaches a rms flux density of ∼50 µJy in band 6 (200-250 GHz) and ∼20 µJy in band 3 (100-130 GHz). This is an order of magnitude deeper than single-dish 850 µm observat…