Search Publications
The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample
Nowak, G.; Adamów, M.; Niedzielski, A. +3 more
Context. Our knowledge of the intrinsic parameters of exoplanets is as precise as our determinations of their stellar hosts parameters. In the case of radial velocity searches for planets, stellar masses appear to be crucial. But before estimating stellar masses properly, detailed spectroscopic analysis is essential. With this paper we conclude a …
The chemical composition of the oldest nearby open cluster Ruprecht 147
Fu, Xiaoting; Mucciarelli, Alessio; Bragaglia, Angela +2 more
Context. Ruprecht 147 (NGC 6774) is the closest old open cluster, with a distance of less than 300 pc and an age of about 2.5 Gyr. It is therefore well suited for testing stellar evolution models and for obtaining precise and detailed chemical abundance information.
Aims: We combined photometric and astrometric information coming from literat…
Dynamical ages of the young local associations with Gaia
Miret-Roig, N.; Figueras, F.; Antoja, T. +1 more
Context. The young local associations (YLAs) constitute an excellent sample for the study of a variety of astrophysical topics, especially the star formation process in low-density environments. Data from the Gaia mission allows us to undertake studies of the YLAs with unprecedented accuracy.
Aims: We determine the dynamical age and place of …
Cold electrons at comet 67P/Churyumov-Gerasimenko
Henri, P.; Rubin, M.; Vigren, E. +4 more
Context. The electron temperature of the plasma is one important aspect of the environment. Electrons created by photoionization or impact ionization of atmospheric gas have energies 10 eV. In an active comet coma, the gas density is high enough for rapid cooling of the electron gas to the neutral gas temperature (a few hundred kelvin). How coolin…
Precise weak lensing constraints from deep high-resolution Ks images: VLT/HAWK-I analysis of the super-massive galaxy cluster RCS2 J 232727.7-020437 at z = 0.70
Bradač, Maruša; Muzzin, Adam; Schrabback, Tim +16 more
We demonstrate that deep good-seeing VLT/HAWK-I Ks images complemented with g + z-band photometry can yield a sensitivity for weak lensing studies of massive galaxy clusters at redshifts 0.7 ≲ z ≲ 1.1, which is almost identical to the sensitivity of HST/ACS mosaics of single-orbit depth. Key reasons for this good performance are the exc…
A quantitative spectral analysis of 14 hypervelocity stars from the MMT survey
Heber, U.; Irrgang, A.; Kreuzer, S. +1 more
Context. Hypervelocity stars (HVSs) travel so fast that they may leave the Galaxy. The tidal disruption of a binary system by the supermassive black hole in the Galactic center is widely assumed to be their ejection mechanism.
Aims: To test the hypothesis of an origin in the Galactic center using kinematic investigations, the current space ve…
Thermal fracturing on comets. Applications to 67P/Churyumov-Gerasimenko
Jorda, L.; Kührt, E.; Groussin, O. +12 more
We simulate the stresses induced by temperature changes in a putative hard layer near the surface of comet 67P/Churyumov-Gerasimenko with a thermo-viscoelastic model. Such a layer could be formed by the recondensation or sintering of water ice (and dust grains), as suggested by laboratory experiments and computer simulations, and would explain the…
Probing the nature and origin of dust in the reddened quasar IC 4329A with global modelling from X-ray to infrared
Mehdipour, Missagh; Costantini, Elisa
Cosmic dust is a key tracer of structure formation and evolution in the universe. In active galactic nuclei (AGN) the origin and role of dust are uncertain. Here, we have studied dust in the X-ray bright and reddened type-1 quasar IC 4329A, which exhibits an ionised AGN wind. We incorporated high-resolution X-ray and mid-IR spectroscopy, combined …
The WISSH quasars project. V. ALMA reveals the assembly of a giant galaxy around a z = 4.4 hyper-luminous QSO
Fiore, F.; Marconi, A.; Piconcelli, E. +11 more
We present an ALMA high-resolution (0.18″ × 0.21″) observation of the 840 µm continuum and [CII] λ157.74 µm line emission in the WISE-SDSS selected hyper-luminous (WISSH) quasi-stellar object (QSO) J1015+0020, at z ∼ 4.4. Our analysis reveals an exceptional overdensity of [CII]-emitting companions with a very small (<150 km s-1…
Intense C III] λλ1907,1909 emission from a strong Lyman continuum emitting galaxy
Chisholm, J.; Schaerer, D.; Thuan, T. X. +5 more
We have obtained the first complete ultraviolet (UV) spectrum of a strong Lyman continuum (LyC) emitter at low redshift - the compact, low-metallicity, star-forming galaxy J1154+2443 - with a Lyman continuum escape fraction of 46% discovered recently. The Space Telescope Imaging Spectrograph spectrum shows strong Lyα and C III] λ1909 emission, as …