Search Publications
Extending optical flare models to the UV: results from comparing of TESS and GALEX flare observations for M Dwarfs
Loyd, R. O. Parke; Jackman, James A. G.; Richey-Yowell, Tyler +3 more
The ultraviolet (UV) emission of stellar flares may have a pivotal role in the habitability of rocky exoplanets around low-mass stars. Previous studies have used white-light observations to calibrate empirical models which describe the optical and UV flare emission. However, the accuracy of the UV predictions of models has previously not been test…
The extended 'stellar halo' of the Ursa Minor dwarf galaxy
Sestito, Federico; Jensen, Jaclyn; McConnachie, Alan W. +9 more
Stellar candidates in the Ursa Minor (UMi) dwarf galaxy have been found using a new Bayesian algorithm applied to Gaia EDR3 data. Five of these targets are located in the extreme outskirts of UMi, from ~5 to 12 elliptical half-light radii (rh), where rh(UMi) = 17.32 ± 0.11 arcmin, and have been observed with the high-resoluti…
Galaxy interactions are the dominant trigger for local type 2 quasars
Ramos Almeida, C.; Tadhunter, C.; Pierce, J. C. S. +8 more
The triggering mechanism for the most luminous, quasar-like active galactic nuclei (AGN) remains a source of debate, with some studies favouring triggering via galaxy mergers, but others finding little evidence to support this mechanism. Here, we present deep Isaac Newton Telescope/Wide Field Camera imaging observations of a complete sample of 48 …
15 000 ellipsoidal binary candidates in TESS: Orbital periods, binary fraction, and tertiary companions
Maoz, Dan; Rix, Hans-Walter; Green, Matthew J. +5 more
We present a homogeneously selected sample of 15 779 candidate binary systems with main sequence primary stars and orbital periods shorter than 5 d. The targets were selected from TESS full-frame image light curves on the basis of their tidally induced ellipsoidal modulation. Spectroscopic follow-up suggests a sample purity of 83 ± 13 per cent. In…
Euclid preparation - XXIII. Derivation of galaxy physical properties with deep machine learning using mock fluxes and H-band images
Cimatti, A.; Aghanim, N.; Burigana, C. +197 more
Next-generation telescopes, like Euclid, Rubin/LSST, and Roman, will open new windows on the Universe, allowing us to infer physical properties for tens of millions of galaxies. Machine-learning methods are increasingly becoming the most efficient tools to handle this enormous amount of data, because they are often faster and more accurate than tr…
The origin and fate of the Gaia phase-space snail
Bovy, Jo; Tremaine, Scott; Frankel, Neige
The Gaia snail is a spiral feature in the distribution of solar-neighbourhood stars in position and velocity normal to the Galactic midplane. The snail probably arises from phase mixing of gravitational disturbances that perturbed the disc in the distant past. The most common hypothesis is that the primary disturbance resulted from a passage of th…
CO or no CO? Narrowing the CO abundance constraint and recovering the H2O detection in the atmosphere of WASP-127 b using SPIRou
Vinatier, Sandrine; Gaidos, Eric; Cowan, Nicolas B. +24 more
Precise measurements of chemical abundances in planetary atmospheres are necessary to constrain the formation histories of exoplanets. A recent study of WASP-127 b, a close-in puffy sub-Saturn orbiting its solar-type host star in 4.2 d, using Hubble Space Telescope (HST) and Spitzer revealed a feature-rich transmission spectrum with strong excess …
Massive dark matter haloes at high redshift: implications for observations in the JWST era
Wang, Kai; Chen, Yangyao; Mo, H. J.
The presence of massive galaxies at high z as recently observed by JWST appears to contradict the current ΛCDM cosmology. Here, we aim to alleviate this tension by incorporating uncertainties from three sources in counting galaxies: cosmic variance, error in stellar mass estimation, and backsplash enhancement. Each of these factors significantly i…
Dynamically constraining the length of the Milky way bar
Price-Whelan, Adrian M.; Hawkins, Keith; Lucey, Madeline +5 more
We present a novel method for constraining the length of the Galactic bar using 6D phase-space information to directly integrate orbits. We define a pseudo-length for the Galactic bar, named RFreq, based on the maximal extent of trapped bar orbits. We find the RFreq measured from orbits is consistent with the RFreq…
Signs of environmental effects on star-forming galaxies in the Spiderweb protocluster at z = 2.16
Tanaka, I.; Dannerbauer, H.; Daikuhara, K. +11 more
We use multi-object near-infrared spectroscopy with VLT/KMOS to investigate the role of the environment in the evolution of the ionized gas properties of narrow-band-selected H α emitters (HAEs) in the Spiderweb protocluster at z = 2.16. Based on rest-frame optical emission lines, H α and [N II]λ6584, we confirm the cluster membership of 39 of our…