Search Publications
Bending waves in the Milky Way's disc from halo substructure
Widrow, Lawrence M.; Chequers, Matthew H.; Darling, Keir
We use N-body simulations to investigate the excitation of bending waves in a Milky Way-like disc-bulge-halo system. The dark matter halo consists of a smooth component and a population of subhaloes, while the disc is composed of thin and thick components. Also, considered is a control simulation where all of the halo mass is smoothly distributed.…
Heavy X-ray obscuration in the most luminous galaxies discovered by WISE
Stern, D.; Brandt, W. N.; Comastri, A. +11 more
Hot dust-obscured galaxies (DOGs) are hyperluminous (L8-1000 µm > 1013 L⊙) infrared galaxies with extremely high (up to hundreds of K) dust temperatures. The sources powering both their extremely high luminosities and dust temperatures are thought to be deeply buried and rapidly accreting supermassive blac…
Spiral arm crossings inferred from ridges in Gaia stellar velocity distributions
Steinmetz, Matthias; Chiappini, Cristina; Minchev, Ivan +7 more
The solar neighbourhood contains disc stars that have recently crossed spiral arms in the Galaxy. We propose that boundaries in local velocity distributions separate stars that have recently crossed and been more strongly perturbed by a particular arm from those that haven't. Ridges in the stellar velocity distributions constructed from the second…
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…
GAMA/G10-COSMOS/3D-HST: Evolution of the galaxy stellar mass function over 12.5 Gyr
Robotham, A. S. G.; Driver, S. P.; Wright, A. H.
Using a combined and consistently analysed GAMA, G10-COSMOS, and 3D-HST data set, we explore the evolution of the galaxy stellar mass function over lookback times t_L \in [0.2,12.5] { h^{-1}_{70} Gyr}. We use a series of volume-limited samples to fit Schechter functions in bins of ∼constant lookback time and explore the evolution of the best-fitti…
Is the Milky Way still breathing? RAVE-Gaia streaming motions
Gilmore, G.; Freeman, K. C.; Watson, F. +26 more
We use data from the Radial Velocity Experiment (RAVE) and the Tycho-Gaia astrometric solution (TGAS) catalogue to compute the velocity fields yielded by the radial (VR), azimuthal (Vϕ),and vertical (Vz) components of associated Galactocentric velocity. We search in particular for variation in all three velocity co…