Search Publications
Environmental processing in cluster core galaxies at z = 1.7
Castignani, G.; Combes, F.; Salomé, P.
Today, the brightest cluster galaxies (BCGs) are passive and very massive galaxies at the center of their clusters, and they still accrete mass through swallowing companions and gas from cooling flows. However their formation history is not well known. We report CO(4→3) and continuum map observations of the SpARCS1049+56 BCG at z = 1.709, one of t…
Galaxy and mass assembly: luminosity and stellar mass functions in GAMA groups
Wang, L.; Brough, S.; Holwerda, B. W. +14 more
How do galaxy properties (such as stellar mass, luminosity, star formation rate, and morphology) and their evolution depend on the mass of their host dark matter halo? Using the Galaxy and Mass Assembly group catalogue, we address this question by exploring the dependence on host halo mass of the luminosity function (LF) and stellar mass function …
Steady Wind-blown Cavities within Infalling Rotating Envelopes: Application to the Broad Velocity Component in Young Protostars
Johnstone, Doug; Cabrit, Sylvie; Kristensen, Lars E. +1 more
Wind-driven outflows are observed around a broad range of accreting objects throughout the universe, ranging from forming low-mass stars to supermassive black holes. We study the interaction between a central isotropic wind and an infalling, rotating envelope, which determines the steady-state cavity shape formed at their interface under the assum…
A Small-scale Filament Eruption Inducing a Moreton Wave, an EUV Wave, and a Coronal Mass Ejection
Xue, Zhike; Yan, Xiaoli; Wang, Jincheng +3 more
With the launch of the Solar Dynamic Observatory, many extreme ultraviolet (EUV) waves have been observed during solar eruptions. However, joint observations of Moreton and EUV waves are still relatively rare. We present an event in active region NOAA 12740 wherein a small-scale filament eruption simultaneously results in a Moreton wave, an EUV wa…
Ganymede's Far-Ultraviolet Reflectance: Constraining Impurities in the Surface Ice
Nichols, J. D.; Raut, U.; Retherford, K. D. +2 more
We present reflectance spectra of Ganymede's leading and trailing hemispheres in the wavelength range 138-215 nm, obtained by the Hubble Space Telescope Cosmic Origins Spectrograph (HST/COS) in 2014. The most notable feature of both spectra is the absence of a sharp water absorption edge at ~165 nm, seen in laboratory measurements of ice reflectiv…
Cloud Atlas: High-precision HST/WFC3/IR Time-resolved Observations of Directly Imaged Exoplanet HD 106906b
Schneider, Glenn; Metchev, Stanimir; Apai, Dániel +10 more
HD 106906b is an $\sim 11{M}_{\mathrm{Jup}}, ∼15 Myr old directly imaged exoplanet orbiting at an extremely large distance from its host star. The wide separation (7"11) between HD 106906b and its host star greatly reduces the difficulty in direct-imaging observations, making it one of the most favorable directly imaged exoplanets for detailed cha…
Identifying Active Kelvin-Helmholtz Vortices on Saturn's Magnetopause Boundary
Delamere, P. A.; Johnson, J. R.; Burkholder, B. L. +1 more
For ∼2,000 Cassini magnetopause encounters, we analyse plasma and magnetic fields. The boundary can be unstable to the Kelvin-Helmholtz instability (KHI), which can drive large-scale flows identifiable in plasma measurements. Bulk flow reversed from the expected direction near the magnetopause can indicate vorticity associated with active KH, and …
Linking the small-scale relativistic winds and the large-scale molecular outflows in the z = 1.51 lensed quasar HS 0810+2554
Cappi, M.; Vignali, C.; Comastri, A. +7 more
We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of the quadruply lensed z = 1.51 quasar HS 0810+2554 which provide useful insight on the kinematics and morphology of the CO molecular gas and the ∼ 2 mm-continuum emission in the quasar host galaxy. Lens modelling of the mm-continuum and the spectrally integrated CO(J = 3…
Properties of the Milky Way's Old Populations Based on Photometric Metallicities of the OGLE RR Lyrae Stars
Soszyński, I.; Udalski, A.; Szymański, M. K. +11 more
We have used photometric data on almost 91 000 fundamental-mode RR Lyr stars (type RRab) detected by the OGLE survey to investigate properties of old populations in the Milky Way. Based on their metallicity distributions, we demonstrate that the Galaxy is built from three distinct old components: halo, bulge, and disk. The distributions reach thei…
An ancient double degenerate merger in the Milky Way halo
Vennes, Stéphane; Ferrario, Lilia; Kawka, Adela
We present an analysis and re-appraisal of the massive, carbon-enriched (DQ) white dwarf (WD) LP 93-21. Its high mass ( ≈1.1 M⊙) and membership to the class of warm DQ WDs, combined with its peculiar halo kinematics suggest that this object is the product of an ancient stellar merger event, most likely that of two WDs. Furthermore, the …