Search Publications
AGN accretion and black hole growth across compact and extended galaxy evolution phases
Kocevski, Dale D.; Aird, James; Coil, Alison L.
The extent of black hole growth during different galaxy evolution phases and the connection between galaxy compactness and active galactic nucleus (AGN) activity remain poorly understood. We use Hubble Space Telescope imaging of the CANDELS fields to identify star-forming and quiescent galaxies at z = 0.5-3 in both compact and extended phases and …
The effect of hierarchical structure of the surface dust layer on the modelling of comet gas production
Blum, J.; Hartogh, P.; Bentley, M. S. +3 more
A hierarchical model of microstructure of cometary dust seems to accurately capture the morphological complexity of these particles as observed by the Rosetta mission to the 67P/Churyumov-Gerasimenko. The main aim of this work is to investigate how uncertainties in the knowledge of the microstructure of the surface layer affect our estimates of ga…
Exoplanets in the Galactic context: planet occurrence rates in the thin disc, thick disc, and stellar halo of Kepler stars
Bashi, Dolev; Zucker, Shay
In order to gain a better understanding of planet formation and evolution, it is important to examine the statistics of exoplanets in the Galactic context. By combining information on stellar elemental abundances and kinematics, we constructed separate samples of Kepler stars according to their affiliation to the Galactic components of thin disc, …
Probing the Galactic halo with RR lyrae stars - III. The chemical and kinematic properties of the stellar halo
Tian, Haijun; Liu, Gaochao; Huang, Yang +3 more
Based on a large spectroscopic sample of ~4300 RR Lyrae stars with metallicity, systemic radial velocity, and distance measurements, we present a detailed analysis of the chemical and kinematic properties of the Galactic halo. Using this sample, the metallicity distribution function (MDF) as a function of r and the velocity anisotropy parameter β …
The K2-OjOS Project: New and revisited planets and candidates in K2 campaigns 5, 16, & 18
Bonavera, L.; González-Nuevo, J.; Korth, J. +28 more
We present the first results of K2-OjOS, a collaborative project between professional and amateur astronomers primarily aimed to detect, characterize, and validate new extrasolar planets. For this work, 10 amateur astronomers looked for planetary signals by visually inspecting the 20 427 light curves of K2 campaign 18 (C18). They found 42 planet c…
The galaxy-halo size relation of low-mass galaxies in FIRE
Faucher-Giguère, Claude-André; Wetzel, Andrew; Feldmann, Robert +7 more
Galaxy sizes correlate closely with the sizes of their parent dark matter haloes, suggesting a link between halo formation and galaxy growth. However, the precise nature of this relation and its scatter remains to be understood fully, especially for low-mass galaxies. We analyse the galaxy-halo size relation (GHSR) for low-mass ($M_\star \sim 10^{…
Age dissection of the vertical breathing motions in Gaia DR2: evidence for spiral driving
Debattista, Victor P.; Khachaturyants, Tigran; Ghosh, Soumavo
Gaia DR2 has revealed breathing motions in the Milky Way, with stars on both sides of the Galactic mid-plane moving coherently towards or away from it. The generating mechanism of these breathing motions is thought to be spiral density waves. Here, we test this hypothesis. Using a self-consistent, high-resolution simulation with star formation, an…
TESS discovery of a sub-Neptune orbiting a mid-M dwarf TOI-2136
Triaud, Amaury H. M. J.; Latham, David W.; Howell, Steve B. +63 more
We present the discovery of TOI-2136 b, a sub-Neptune planet transiting a nearby M4.5V-type star every 7.85 d, identified through photometric measurements from the Transiting Exoplanet Survey Satellite (TESS) mission. The host star is located 33 pc away with a radius of R* = 0.34 ± 0.02 R⊙, a mass of $0.34\pm 0.02 \, \mathrm{…
Across the green valley with HST grisms: colour evolution, crossing time-scales, and the growth of the red sequence at z = 1.0-1.8
Ravindranath, Swara; Willott, Chris J.; Bradač, Maruša +6 more
We measure the colour evolution and quenching time-scales of z = 1.0-1.8 galaxies across the green valley. We derive rest-frame NUVrK colours and select blue-cloud, green-valley, and red-sequence galaxies from the spectral energy distribution modelling of CANDELS GOODS-South and UDS multiband photometry. Separately, we constrain the star-formation…
XMM-Newton observations of the narrow-line Seyfert 1 galaxy IRAS 13224-3809: X-ray spectral analysis II
Fabian, Andrew C.; Reynolds, Christopher S.; Jiang, Jiachen +4 more
Previously, we modelled the X-ray spectra of the narrow-line Seyfert 1 galaxy IRAS 13224-3809 using a disc reflection model with a fixed electron density of 1015 cm-3. An additional blackbody component was required to fit the soft X-ray excess below 2 keV. In this work, we analyse simultaneously five flux-resolved XMM-Newton …