Search Publications
Uranus ring occultation observations: 1977-2006
Nicholson, Philip D.; French, Richard G.; Sicardy, Bruno +25 more
The Uranian rings were discovered serendipitously on 10 March 1977 during a stellar occultation (Elliot et al., 1977a; Millis et al., 1977), and a rich set of subsequent Earth-based occultations revealed that these narrow and sharp-edged rings were eccentric and inclined, precessing under the gravitational influence of the oblate central planet. C…
Spectropolarimetry and spectral decomposition of high-accreting narrow-line Seyfert 1 galaxies
Czerny, Bożena; Martínez-Aldama, Mary Loli; Panda, Swayamtrupta +7 more
Context. Narrow-line Seyfert 1 (NLSy1) galaxies have been shown to have high Eddington ratios and relatively small black hole mass. The measurement of these black hole masses is based on the virial relation that is dependent on the distribution of the line-emitting gas and the viewing angle to the source. Spectropolarimetry enables us to probe the…
UV-FIR SED modelling of AGNs in IR-luminous galaxies up to z 2.5: understanding the effects of torus models
Pope, A.; Kirkpatrick, A.; Yun, M. +2 more
UV-FIR spectral energy distribution (SED) modelling is an effective way to disentangle emission between star formation (SF) and active galactic nuclei (AGNs) in galaxies; however, this approach becomes uncertain for composite AGNs/SF galaxies that comprise 50-70 per cent of IR-samples. Cosmic X-ray background (XRB) models require a large fraction …
The Temporal Brightening of Uranus' Northern Polar Hood From HST/WFC3 and HST/STIS Observations
Wong, Michael H.; Fletcher, Leigh N.; Irwin, Patrick G. J. +8 more
Hubble Space Telescope Wide-Field Camera 3 (HST/WFC3) observations spanning 2015 to 2021 confirm a brightening of Uranus' north polar hood feature with time. The vertical aerosol model of Irwin et al. (2023, https://doi.org/10.1038/s41550-023-02047-0) (IRW23), consisting of a deep haze layer…
The Accretion History of AGN: The Spectral Energy Distributions of X-Ray-luminous Active Galactic Nuclei
Kirkpatrick, Allison; Koss, Michael; Boquien, Médéric +17 more
Spectral energy distributions (SEDs) from X-ray to far-infrared (FIR) wavelengths are presented for a sample of 1246 X-ray-luminous active galactic nuclei (AGNs; L 0.5-10 keV > 1043 erg s-1), with z spec < 1.2, selected from Stripe 82X, COSMOS, and GOODS-N/S. The rest-frame SEDs show a wide spread …
A Survey of Herbig Ae/Be Multiplicity
Bouvier, J.; Beuzit, J. -L.; Thomas, S. J. +5 more
Although the majority of Herbig Ae/Be (HAEBE) stars are likely multiple systems, relatively few multiples have been identified. We aim to create a statistically significant survey of HAEBE multiplicity as a function of stellar mass, to shed light on mixed-mass star formation. Two independent adaptive optics IR imaging surveys were conducted, betwe…
The ESO UVES/FEROS Large Programs of TESS OB pulsators. I. Global stellar parameters from high-resolution spectroscopy
Sana, Hugues; Bowman, Dominic M.; Aerts, Conny +7 more
Context. Modern stellar structure and evolution theory suffers from a lack of observational calibration for the interior physics of intermediate- and high-mass stars. This leads to discrepancies between theoretical predictions and observed phenomena that are mostly related to angular momentum and element transport. Analyses of large samples of mas…
Searching for magnetic fields in pulsating A-type stars: the discovery of a strong field in the probable δ Sct star HD 340577 and a null result for the γ Dor star HR 8799
Ilyin, I.; Hubrig, S.; Schöller, M. +2 more
Numerous δ Sct and γ Dor pulsators are identified in the region of the Hertzsprung-Russell diagram that is occupied by chemically peculiar magnetic Ap stars. The connection between δ Sct and γ Dor pulsations and the magnetic field in Ap stars is however not clear: theory suggests for magnetic Ap stars some critical field strengths for pulsation mo…
Degree of stochastic asymmetry in the tidal tails of star clusters
Prusti, T.; Beccari, G.; Boffin, H. M. J. +4 more
Context. Tidal tails of star clusters are commonly understood to be populated symmetrically. Recently, the analysis of Gaia data revealed large asymmetries between the leading and trailing tidal tail arms of the four open star clusters Hyades, Praesepe, Coma Berenices, and NGC 752.
Aims: As the evaporation of stars from star clusters into the…
Effects of Temperature on Visible and Infrared Spectra of Mercury Minerals Analogues
Langevin, Yves; Poulet, François; Perna, Davide +12 more
Mercury's peculiar orbit around the Sun (3:2 spin-orbit resonance) and lack of atmosphere result in one the widest temperature ranges experienced at the surface of a planetary body in the solar system. Temperature variations affect the physical and, therefore, spectral properties of minerals to varying degrees; thus, it is crucial to study them in…