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Masses and ages for metal-poor stars. A pilot programme combining asteroseismology and high-resolution spectroscopic follow-up of RAVE halo stars
Valentini, M.; García, R. A.; Chiappini, C. +10 more
Context. Very metal-poor halo stars are the best candidates for being among the oldest objects in our Galaxy. Samples of halo stars with age determination and detailed chemical composition measurements provide key information for constraining the nature of the first stellar generations and the nucleosynthesis in the metal-poor regime.
Aims: A…
Delayed Circumstellar Interaction for Type Ia SN 2015cp Revealed by an HST Ultraviolet Imaging Survey
Fox, O. D.; Smith, M.; Sullivan, M. +11 more
The nature and role of the binary companion of carbon-oxygen white dwarf stars that explode as Type Ia supernovae (SNe Ia) are not yet fully understood. Past detections of circumstellar material (CSM) that contain hydrogen for a small number of SN Ia progenitor systems suggest that at least some have a nondegenerate companion. In order to constrai…
Host galaxies of high-redshift extremely red and obscured quasars
Brandt, W. N.; Ross, Nicholas P.; Strauss, Michael A. +9 more
We present Hubble Space Telescope 1.4-1.6 µm images of the hosts of 10 extremely red quasars (ERQs) and six type 2 quasar candidates at z = 2-3. ERQs, whose bolometric luminosities range between 1047 and 1048 erg s-1, show spectroscopic signs of powerful ionized winds, whereas type 2 quasar candidates are les…
Spectral variations of Lyman α emission within strongly lensed sources observed with MUSE
Richard, J.; Verhamme, A.; Clément, B. +13 more
We present an analysis of H I Lyman α emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at z=3.5 and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman α haloes are intrinsically similar to the ones typically seen in other MUSE deep fields, the benefits of gravitational lensing a…
Multiepoch Ultraviolet HST Observations of Accreting Low-mass Stars
Espaillat, Catherine C.; Robinson, Connor E.
Variability is a defining characteristic of young low-mass stars that are still accreting material from their primordial protoplanetary disk. Here we present the largest Hubble Space Telescope (HST) variability study of classical T Tauri stars (CTTS) to date. For five of these objects, we obtained a total of 25 spectra with the Space Telescope Ima…
Six new supermassive black hole mass determinations from adaptive-optics assisted SINFONI observations
Krajnović, Davor; Sarzi, Marc; Cappellari, Michele +4 more
Different massive black hole mass - host galaxy scaling relations suggest that the growth of massive black holes is entangled with the evolution of their host galaxies. The number of measured black hole masses is still limited and additional measurements are necessary to understand the underlying physics of this apparent coevolution. We add six ne…
Probing the origin of stellar flares on M dwarfs using TESS data sectors 1-3
Doyle, J. G.; Ramsay, G.; Wu, K. +1 more
Detailed studies of the Sun have shown that sunspots and solar flares are closely correlated. Photometric data from Kepler/K2 has allowed similar studies to be carried out on other stars. Here, we utilize Transiting Exoplanet Survey Satellite (TESS) photometric 2-min cadence of 167 low-mass stars from Sectors 1 to 3 to investigate the relationship…
Overcast on Osiris: 3D radiative-hydrodynamical simulations of a cloudy hot Jupiter using the parametrized, phase-equilibrium cloud formation code EDDYSED
Sing, D. K.; Mikal-Evans, T.; Mayne, N. J. +5 more
We present results from 3D radiative-hydrodynamical simulations of HD 209458b with a fully coupled treatment of clouds using the EDDYSED code, critically, including cloud radiative feedback via absorption and scattering. We demonstrate that the thermal and optical structure of the simulated atmosphere is markedly different, for the majority of our…
Interstellar Medium and Star Formation of Starburst Galaxies on the Merger Sequence
Ho, Luis C.; Li, Zhihui; Zhuang, Ming-Yang +3 more
The interstellar medium is a key ingredient that governs star formation in galaxies. We present a detailed study of the infrared (∼1-500 µm) spectral energy distributions of a large sample of 193 nearby (z≲ 0.088) luminous infrared galaxies (LIRGs) covering a wide range of evolutionary stages along the merger sequence. The entire sample has …
Systematic errors in Gaia DR2 astrometry and their impact on measurements of internal kinematics of star clusters
Vasiliev, Eugene
We use stellar proper motions (PM) from Gaia Data Release 2 for studying the internal kinematics of Milky Way globular clusters. In addition to statistical measurement errors, there are significant spatially correlated systematic errors, which cannot be ignored when studying the internal kinematics. We develop a mathematically consistent procedure…