Search Publications
The high energy spectrum of Proxima Centauri simultaneously observed at X-ray and FUV wavelengths
Czesla, S.; France, K.; Predehl, P. +6 more
The M dwarf Proxima Centauri, the Sun's closest stellar neighbour, is known to be magnetically active and it hosts a likely Earth-like planet in its habitable zone. High-energy radiation from the host star can significantly alter planetary atmospheres in close orbits. Frequent flaring may drive radiation-induced effects such as rapid atmospheric e…
Kharkiv database of asteroid absolute magnitudes: Comparative analysis with other datasets
Muinonen, K.; Penttilä, A.; Kwiatkowski, T. +9 more
We present a database of the absolute magnitudes of asteroids named the Kharkiv Asteroid Absolute Magnitude Database (KhAAMD). The database includes a homogeneous set of the absolute magnitudes for about 400 asteroids in the new HG1G2 magnitude system. We performed a comparative analysis of the asteroid absolute magnitudes be…
Masses, bulk densities, and macroporosities of asteroids (15) Eunomia, (29) Amphitrite, (52) Europa, and (445) Edna based on Gaia astrometry
Granvik, M.; Siltala, L.
Context. Gaia Data Release 2 (DR2) includes milliarcsecond-accuracy astrometry for 14 099 asteroids. One of the main expected scientific applications of these data is asteroid mass estimation via the modeling of perturbations during asteroid-asteroid encounters.
Aims: We explore the practical impact of the Gaia astrometry of asteroids for the…
Linking high- and low-mass star formation. Observation-based continuum modelling and physical conditions
Kristensen, L. E.; Jørgensen, J. K.; Pitts, R. L. +1 more
Context. Astronomers have yet to establish whether high-mass protostars form from high-mass prestellar cores, similar to their lower-mass counterparts, or from lower-mass fragments at the heart of a pre-protostellar cluster undergoing large-scale collapse. Part of the uncertainty is due to a shortage of envelope structure data on protostars of a f…
Radial profiles of lensed z ∼ 1 galaxies on sub-kiloparsec scales
Richard, Johan; Chisholm, John; Schaerer, Daniel +4 more
We study the spatially resolved physical properties of the Cosmic Snake arc in MACS J1206.2-0847 and the arc in Abell 0521 (A521). These are two strongly lensed galaxies at redshifts z = 1.036 and z = 1.044. We used observations of the Hubble Space Telescope (HST) and the Atacama Large Millimeter/submillimeter Array (ALMA). The former gives access…
Probing modified Newtonian dynamics with hypervelocity stars
Gallo, Arianna; Ostorero, Luisa; Chakrabarty, Sankha Subhra +2 more
We show that measuring the velocity components of hypervelocity stars (HVSs) can discriminate between modified Newtonian dynamics (MOND) and Newtonian gravity. Hypervelocity stars are ejected from the Galactic center on radial trajectories with a null tangential velocity component in the reference frame of the Galaxy. They acquire tangential compo…
Tomography of the environment of the COSMOS/AzTEC-3 submillimeter galaxy at z ∼ 5.3 revealed by Lyα and MUSE observations
Dannerbauer, H.; Marino, R.; da Cunha, E. +8 more
Context. Submillimeter galaxies (SMGs) have been proposed as the progenitors of massive ellipticals in the local Universe. Mapping the neutral gas distribution and investigating the gas accretion toward the SMGs at high redshift can provide information on the way SMG environments can evolve into clusters at z = 0.
Aims: In this work, we study…
Data reduction and restoration of spectropolarimetric microlensed hyperspectral imager data
van Noort, M.; Doerr, H. -P.
Context. A microlensed hyperspectral imager (MiHI) is an integral field spectrograph based on a double-sided microlens array.
Aims: To convert the raw data frames of such an instrument to hyperspectral cubes, and restore them to high-resolution science-ready Stokes data, a new kind of data reduction procedure is required.
Methods: An opt…
Breaking the rules at z ≃ 0.45: The rebel case of RBS 1055
Stern, D.; Bianchi, S.; Guainazzi, M. +5 more
Context. Very luminous quasars are unique sources for studying the circumnuclear environment around supermassive black holes. Several components contribute to the overall X-ray spectral shape of active galactic nuclei (AGN). The hot (kTe = 50 − 100 keV) and warm (kTe = 0.1 − 1 keV) coronae are responsible for the hard and sof…
Empirical relations between the intensities of Lyman lines of H and He+
Vial, J. -C.; Auchère, F.; Bocchialini, K. +9 more
Context. Empirical relations between major UV and extreme UV spectral lines are one of the inputs for models of chromospheric and coronal spectral radiances and irradiances. They are also needed for the interpretation of some of the observations of the Solar Orbiter mission.
Aims: We aim to determine an empirical relation between the intensit…