Search Publications
Accurate oxygen abundance of interstellar gas in Mrk 71 from optical and infrared spectra
Weiner, Benjamin; Spilker, Justin; Fadda, Dario +9 more
The heavy element content (`metallicity') of the Universe is a record of the total star formation history. Gas-phase metallicity in galaxies, as well as its evolution with time, is of particular interest as a tracer of accretion and outflow processes. However, metallicities from the widely used electron temperature (Te) method are typic…
Universality in the random walk structure function of luminous quasi-stellar objects
Tang, Ji-Jia; Wolf, Christian; Tonry, John
Rapidly growing black holes are surrounded by accretion disks that make them the brightest objects in the Universe. Their brightness is known to be variable, but the causes of this are not implied by simple disk models and still debated. Due to the small size of accretion disks and their great distance, there are no resolved images addressing the …
The use of double-mode RR Lyrae stars as robust distance and metallicity indicators
Wang, Shu; Deng, Licai; Chen, Xiaodian +1 more
RR Lyrae stars are one of the primary distance indicators for old stellar populations such as globular clusters, dwarf galaxies and galaxies. Typically, fundamental-mode RR Lyr stars are used for distance measurements, and their accuracy is strongly limited by the dependence of absolute magnitudes on metallicity, in both the optical and infrared b…
Photochemical depletion of heavy CO isotopes in the Martian atmosphere
Montmessin, Franck; Belyaev, Denis A.; Fedorova, Anna A. +12 more
The atmosphere of Mars is enriched in heavy isotopes with respect to Earth as a result of the escape of the atmosphere to space over billions of years. Estimating this enrichment requires a rigorous understanding of all atmospheric processes that contribute to the evolution of isotopic ratios between the lower and upper atmosphere, where escape pr…
An intense narrow equatorial jet in Jupiter's lower stratosphere observed by JWST
de Pater, Imke; Wong, Michael H.; Fletcher, Leigh N. +18 more
The atmosphere of Jupiter has east-west zonal jets that alternate as a function of latitude as tracked by cloud motions at tropospheric levels. Above and below the cold tropopause at ~100 mbar, the equatorial atmosphere is covered by hazes at levels where thermal infrared observations used to characterize the dynamics of the stratosphere lose part…
Vertical wind structure in an X-ray binary revealed by a precessing accretion disk
Fabian, A. C.; Reynolds, C. S.; Pinto, C. +11 more
The accretion of matter onto black holes and neutron stars often leads to the launching of outflows that can greatly affect the environments surrounding the compact object. An important means of studying these winds is through X-ray absorption line spectroscopy, which allows us to probe their properties along a single sightline, but usually provid…
Whistler-mode waves in Mercury's magnetosphere observed by BepiColombo/Mio
Sahraoui, Fouad; Kasaba, Yasumasa; Omura, Yoshiharu +10 more
Whistler-mode chorus waves are natural electromagnetic emissions known to play a key role in electron acceleration and loss mechanisms via wave-particle interactions in planetary magnetospheres. Chorus waves have not yet been detected in Mercury's magnetosphere due to the lack of suitable instruments in the probes that previously visited the plane…
An irradiated-Jupiter analogue hotter than the Sun
Maoz, Dan; Hallakoun, Na'ama; Leibundgut, Bruno +10 more
Planets orbiting close to hot stars experience intense extreme-ultraviolet radiation, potentially leading to atmosphere evaporation and to thermal dissociation of molecules. However, this extreme regime remains mainly unexplored due to observational challenges. Only a single known ultra-hot giant planet, KELT-9b, receives enough ultraviolet radiat…
Strong gravitational lensing by AGNs as a probe of the quasar-host relations in the distant Universe
Djorgovski, S. G.; Courbin, Frédéric; Sluse, Dominique +4 more
The tight correlations found between the mass of supermassive black holes and the luminosities, stellar masses and velocity dispersions of their host galaxies are often interpreted as a sign of their co-evolution. Studying these correlations across redshift provides a powerful insight into the evolutionary path followed by the quasar and its host …
A strangely light neutron star within a supernova remnant
Doroshenko, Victor; Santangelo, Andrea; Pühlhofer, Gerd +1 more
To constrain the equation of state of cold dense matter, astrophysical measurements are essential. These are mostly based on observations of neutron stars in the X-ray band, and, more recently, also on gravitational wave observations. Of particular interest are observations of unusually heavy or light neutron stars which extend the range of centra…