Search Publications
Is stellar multiplicity universal? Tight stellar binaries in the Orion nebula Cluster
Duchêne, G.; Bouvier, J.; Lacour, S. +2 more
We present a survey for the tightest visual binaries among 0.3-2 M⊙ members of the Orion nebula Cluster (ONC). Among 42 targets, we discovered 13 new 0.025-0.15 arcsec companions. Accounting for the Branch bias, we find a companion star fraction (CSF) in the 10-60 au range of 21^{+8}_{-5} per cent, consistent with that observed in other…
New PARSEC data base of α-enhanced stellar evolutionary tracks and isochrones - I. Calibration with 47 Tuc (NGC 104) and the improvement on RGB bump
Fu, Xiaoting; Girardi, Léo; Marigo, Paola +4 more
Precise studies on the Galactic bulge, globular cluster, Galactic halo, and Galactic thick disc require stellar models with α enhancement and various values of helium content. These models are also important for extra-Galactic population synthesis studies. For this purpose, we complement the existing PARSEC models, which are based on the solar par…
Dark matter contraction and stellar-mass-to-light ratio gradients in massive early-type galaxies
Auger, Matthew W.; Oldham, Lindsay J.
We present models for the dark and luminous mass structure of 12 strong lensing early-type galaxies. We combine pixel-based modelling of multiband Hubble Space Telescope imaging with Jeans modelling of kinematics obtained from Keck/ESI spectra to disentangle the dark and luminous contributions to the mass. Assuming a generalised NFW (gNFW) profile…
Gravitational lensing reveals extreme dust-obscured star formation in quasar host galaxies
Ivison, R. J.; McKean, J. P.; Isaak, K. G. +8 more
We have observed 104 gravitationally lensed quasars at z ∼ 1-4 with Herschel/SPIRE, the largest such sample ever studied. By targeting gravitational lenses, we probe intrinsic far-infrared (FIR) luminosities and star formation rates (SFRs) more typical of the population than the extremely luminous sources that are otherwise accessible. We detect 7…
Connecting the X-ray properties of weak-line and typical quasars: testing for a geometrically thick accretion disk
Brandt, W. N.; Shen, Yue; Luo, B. +8 more
We present X-ray and multiwavelength analyses of 32 weak emission-line quasars (WLQs) selected in a consistent and unbiased manner. New Chandra 3.1-4.8 ks observations were obtained for 14 of these WLQs with C IV rest-frame equivalent widths (REWs) of 5-15 Å, and these serve as an X-ray observational "bridge" between previously studied WLQs with C…
Resolving Quiescent Galaxies at z ≳ 2. I. Search for Gravitationally Lensed Sources and Characterization of Their Structure, Stellar Populations, and Line Emission
Ellis, Richard S.; Belli, Sirio; Newman, Andrew B. +1 more
Quiescent galaxies at z ≳ 2 are compact and have weak or absent emission lines, making it difficult to spatially resolve their kinematics and stellar populations using ground-based spectroscopy. Gravitationally lensed examples provide a promising route forward, but such objects are very rare. We describe a search in the fields of 232 galaxy cluste…
Introducing a New Inventory of Large Martian Landslides
Crosta, G. B.; Frattini, P.; Valbuzzi, E. +1 more
Landslides have been observed in different terrestrial environments and also on planets, satellites, and asteroids. Long runout landslides are strongly dependent on the initial mass position, material and slope path properties, topographic relief, and presence of volatiles. Therefore, landslides represent a means for the description of rock proper…
Rings and Gaps in Protoplanetary Disks: Planets or Snowlines?
Williams, Jonathan P.; van der Marel, Nienke; Bruderer, Simon
High-resolution Atacama Large Millimeter/submillimeter Array observations of protoplanetary disks have revealed that many, if not all, primordial disks consist of ring-like dust structures. The origin of these dust rings remains unclear, but a common explanation is the presence of planetary companions that have cleared gaps along their orbit and t…
In situ collection of dust grains falling from Saturn's rings into its atmosphere
Postberg, Frank; Schmidt, Jürgen; Spahn, Frank +16 more
Saturn's main rings are composed of >95% water ice, and the nature of the remaining few percent has remained unclear. The Cassini spacecraft's traversals between Saturn and its innermost D ring allowed its cosmic dust analyzer (CDA) to collect material released from the main rings and to characterize the ring material infall into Saturn. We rep…
Transverse Wave Induced Kelvin-Helmholtz Rolls in Spicules
De Pontieu, B.; Schmit, D.; Pereira, T. M. D. +2 more
In addition to their jet-like dynamic behavior, spicules usually exhibit strong transverse speeds, multi-stranded structure, and heating from chromospheric to transition region temperatures. In this work we first analyze Hinode and IRIS observations of spicules and find different behaviors in terms of their Doppler velocity evolution and collectiv…