Search Publications
Astrometric mass measurement of compact companions in binary systems with Gaia
Liu, Jifeng; Gao, Jian; Liao, Shilong +3 more
Context. For binary systems with an unseen primary and a luminous secondary, the astrometric wobble of the secondary could be used to study the primary. With Gaia, it is possible to measure the mass of the black hole or neutron star with a luminous companion (hereafter BH/NS-LC).
Aims: Our aim is to provide a method for predicting Gaia's abil…
He-star donor AM CVn stars and their progenitors as LISA sources
Yungelson, L.; Liu, W. -M.; Kuranov, A.
Context. Ultracompact cataclysmic variables (CVs) of the AM CVn type are deemed to be important verification sources for the future space gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA).
Aims: We model the present-day Galactic population of AM CVn stars with He-star donors. Such a population has long expecte…
A first eROSITA view of ultracool dwarfs
Salvato, M.; Stelzer, B.; Coffaro, M. +2 more
We present the first X-ray detections of ultracool dwarfs (UCDs) from the first all-sky survey of the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) onboard the Russian Spektrum-Roentgen-Gamma mission. We use three publicly available input catalogs of spectroscopically confirmed UCDs and Gaia-selected UCD candidates that togeth…
Emission line star catalogues post-Gaia DR3. A validation of Gaia DR3 data using the LAMOST OBA emission catalogue
Arun, R.; Manoj, P.; Paul, K. T. +9 more
Aims.Gaia Data Release 3 (DR3) and further releases have the potential to identify and categorise new emission-line stars in the Galaxy. We perform a comprehensive validation of astrophysical parameters from Gaia DR3 with the spectroscopically estimated emission-line star parameters from the LAMOST OBA emission catalogue. Method. We compare differ…
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…