Search Publications
The Hubble Space Telescope UV Legacy Survey of Galactic globular clusters - XXI. Binaries among multiple stellar populations
Salaris, M.; Anderson, J.; Milone, A. P. +17 more
A number of scenarios for the formation of multiple populations in globular clusters (GCs) predict that second generation (2G) stars form in a compact and dense subsystem embedded in a more extended first-generation (1G) system. If these scenarios are accurate, a consequence of the denser 2G formation environment is that 2G binaries should be more…
A versatile tool for cluster lensing source reconstruction - I. Methodology and illustration on sources in the Hubble Frontier Field Cluster MACS J0717.5+3745
Treu, Tommaso; Birrer, Simon; Yang, Lilan
We describe a general-purpose method to reconstruct the intrinsic properties of sources lensed by the gravitational potential of foreground clusters of galaxies. The tool LENSTRUCTION is implemented in the publicly available multipurpose gravitational lensing software LENSTRONOMY, in order to provide an easy and fast solution to this common astrop…
An expanded catalogue of low surface brightness galaxies in the Coma cluster using Subaru/Suprime-Cam
Forbes, Duncan A.; Romanowsky, Aaron J.; Alabi, Adebusola B. +2 more
We present a catalogue of low surface brightness (LSB) galaxies in the Coma cluster obtained from deep Subaru/Suprime-Cam V- and R-band imaging data within a region of $\mathord {\sim }4$ deg2. We increase the number of LSB galaxies presented in Yagi et al. (2016) by a factor of $\mathord {\sim }3$ and report the discovery of 29 new ult…
A spectroscopic test of the rotational modulation origin of periodic Kepler photometric variability of A-type stars
Wade, G. A.; Sikora, J.; Rowe, J.
High-precision space-based photometry obtained by the Kepler and TESS missions has revealed evidence of rotational modulation associated with main-sequence (MS) A- and late B-type stars. Generally, such variability in these objects is attributed to inhomogeneous surface structures (e.g. chemical spots), which are typically linked to strong magneti…
Activity and differential rotation of the early M dwarf Kepler-45 from transit mapping
Marsden, S. C.; Carter, B. D.; Valio, A. +1 more
Little is known of the activity and differential rotation of low luminosity, early M dwarfs from direct observation. We present the first stellar activity analysis of star-spots and faculae for the hot Jupiter hosting M1V dwarf Kepler-45 from Kepler transit light curves. We find star-spot and facula temperatures contrasting a few hundred degrees w…
Braking indices of young radio pulsars: theoretical perspective
Igoshev, Andrei P.; Popov, Sergei B.
Recently, Parthsarathy et al. analysed long-term timing observations of 85 young radio pulsars. They found that 15 objects have absolute values of braking indices ranging ∼10-3000, far from the classical value n = 3. They also noted a mild correlation between measured value of n and characteristic age of a radio pulsar. In this article, we systema…
From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc
Xiang, Maosheng; Rix, Hans-Walter; El-Badry, Kareem +3 more
Stars born at the same time in the same place should have formed from gas of the same element composition. But most stars subsequently disperse from their birth siblings, in orbit and orbital phase, becoming 'field stars'. Here, we explore and provide direct observational evidence for this process in the Milky Way disc, by quantifying the probabil…
Differences and similarities of stellar populations in LAEs and LBGs at z ∼ 3.4-6.8
Boquien, M.; Hernán-Caballero, A.; Arrabal Haro, P. +6 more
Lyman alpha emitters (LAEs) and Lyman break galaxies (LBGs) represent the most common groups of star-forming galaxies at high z, and the differences between their inherent stellar populations (SPs) are a key factor in understanding early galaxy formation and evolution. We have run a set of SP burst-like models for a sample of 1558 sources at 3.4 &…
Constraining the distance to the North Polar Spur with Gaia DR2
Alves, João; Speagle, Joshua S.; Zucker, Catherine +3 more
The North Polar Spur (NPS) is one of the largest structures observed in the Milky Way in both the radio and soft X-rays. While several predictions have been made regarding the origin of the NPS, modelling the structure is difficult without precise distance constraints. In this paper, we determine accurate distances to the southern terminus of the …
New insight into the stellar mass function of Galactic globular clusters
Hilker, M.; Baumgardt, H.; Sollima, A. +2 more
We present the results of the analysis of deep photometric data of 32 Galactic globular clusters. We analysed 69 parallel field images observed with the Wide Field Channel of the Advanced Camera for Surveys of the Hubble Space Telescope which complemented the already available photometry from the globular cluster treasury project covering the cent…