Search Publications
Quantifying the structure of strong gravitational lens potentials with uncertainty-aware deep neural networks
Vernardos, Georgios; Tsagkatakis, Grigorios; Pantazis, Yannis
Gravitational lensing is a powerful tool for constraining substructure in the mass distribution of galaxies, be it from the presence of dark matter sub-haloes or due to physical mechanisms affecting the baryons throughout galaxy evolution. Such substructure is hard to model and is either ignored by traditional, smooth modelling, approaches, or tre…
Titan's neutral atmosphere seasonal variations up to the end of the Cassini mission
Flasar, F. M.; Lavvas, P.; Coustenis, A. +4 more
In this paper we report new results concerning the seasonal atmospheric evolution near Titan's poles and equator in terms of temperature and composition using nadir spectra acquired by the Cassini Composite Infrared Spectrometer (CIRS) at high spectral resolution during the last year of the Cassini mission in 2017 complementing previous investigat…
Detection of Pb II in the Ultraviolet Spectra of Three Metal-poor Stars
Beers, Timothy C.; Placco, Vinicius M.; Holmbeck, Erika M. +8 more
We report the first detection of the Pb II line at 2203.534 Šin three metal-poor stars, using ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. We perform a standard abundance analysis assuming local thermodynamic equilibrium (LTE) to derive lead (Pb, Z = 82) abundances. The Pb II line …
The large-scale magnetic field of the eccentric pre-main-sequence binary system V1878 Ori
Hussain, G. A. J.; Alecian, E.; Kochukhov, O. +4 more
We report time-resolved, high-resolution optical spectropolarimetric observations of the young double-lined spectroscopic binary V1878 Ori. Our observations were collected with the ESPaDOnS spectropolarimeter at the Canada-France-Hawaii Telescope through the BinaMIcS large programme. V1878 Ori A and B are partially convective intermediate mass wea…
Tracking the year-to-year variation in the spectral energy distribution of the narrow-line Seyfert 1 galaxy Mrk 335
Komossa, S.; Gallo, L. C.; Grupe, D. +5 more
Multiwavelength monitoring of Mrk 335 with Swift between 2007 and 2019 are used to construct annual spectral energy distributions (SEDs) and track year-to-year changes. Non-contemporaneous archival data prior to 2007 are used to build a bright state SED. In this work, the changes are examined and quantified to build the foundation for future SED m…
Detection of green line emission in the dayside atmosphere of Mars from NOMAD-TGO observations
Aoki, S.; Vandaele, A. C.; Daerden, F. +13 more
The oxygen emission at 557.7 nm is a ubiquitous component of the spectrum of the terrestrial polar aurora and the reason for its usual green colour1. It is also observed as a thin layer of glow surrounding the Earth near 90 km altitude in the dayside atmosphere2,3 but it has so far eluded detection in other planets. Here we r…
The Archetypal Ultra-diffuse Galaxy, Dragonfly 44, Is not a Dark Milky Way
Bogdán, Ákos
Due to the peculiar properties of ultra-diffuse galaxies (UDGs), understanding their origin presents a major challenge. Previous X-ray studies demonstrated that the bulk of UDGs lack substantial X-ray emission, implying that they reside in low-mass dark matter halos. This result, in concert with other observational and theoretical studies, pointed…
Deuterated Polycyclic Aromatic Hydrocarbons in the Interstellar Medium: The C-D Band Strengths of Monodeuterated Species
Li, Aigen; Yang, X. J.; Glaser, R.
Deuterium (D) is one of the light elements created in the Big Bang. As the Galaxy evolves, the D/H abundance in the interstellar medium (ISM) decreases from its primordial value due to astration. However, the observed gas-phase D/H abundances of some sightlines in the local Galactic ISM are substantially lower than the expected reduction by astrat…
Study of the low-order Δν-ρ¯ relation for moderately rotating δ Scuti stars and its impact on their characterization
Suárez, J. C.; García Hernández, A.; Rodón, J. R. +1 more
The large separation in the low-radial order regime is considered as a highly valuable observable to derive mean densities of δ Scuti stars, due to its independence with rotation. Up to now, theoretical studies of this Δν- ${\bar{\rho}}$ relation have been limited to 1D non-rotating models and 2D pseudo-evolutionary models. The present work aims a…
Two new double-lined spectroscopic binary white dwarfs
Bergeron, P.; Kilic, Mukremin; Bédard, A. +1 more
We present radial velocity observations of four binary white dwarf candidates identified through their overluminosity. We identify two new double-lined spectroscopic binary systems, WD 0311-649 and WD 1606+422, and constrain their orbital parameters. WD 0311-649 is a 17.7 h period system with a mass ratio of 1.44 ± 0.06 and WD 1606+422 is a 20.1 h…