Search Publications
The evolution of surface magnetic fields in young solar-type stars II: the early main sequence (250-650 Myr)
Donati, J. -F.; Petit, P.; Vidotto, A. A. +6 more
There is a large change in surface rotation rates of sun-like stars on the pre-main sequence and early main sequence. Since these stars have dynamo-driven magnetic fields, this implies a strong evolution of their magnetic properties over this time period. The spin-down of these stars is controlled by interactions between stellar and magnetic field…
Evidence for a variable Ultrafast Outflow in the newly discovered Ultraluminous Pulsar NGC 300 ULX-1
Fabian, A. C.; Pinto, C.; Bachetti, M. +5 more
Ultraluminous pulsars are a definite proof that persistent super-Eddington accretion occurs in nature. They support the scenario according to which most Ultraluminous X-ray Sources (ULXs) are super-Eddington accretors of stellar mass rather than sub-Eddington intermediate mass black holes. An important prediction of theories of supercritical accre…
Retrieval of planetary and stellar properties in transmission spectroscopy with AURA
Madhusudhan, Nikku; Apai, Dániel; Rackham, Benjamin V. +1 more
Transmission spectroscopy provides a powerful probe of the atmospheric properties of transiting exoplanets. To date, studies of exoplanets in transit have focused on inferring their atmospheric properties such as chemical compositions, cloud/haze properties, and temperature structures. However, surface inhomogeneities in the host stars of exoplane…
Age as a major factor in the onset of multiple populations in stellar clusters
Martocchia, S.; Dalessandro, E.; Salaris, M. +16 more
It is now well established that globular clusters (GCs) exhibit star-to-star light-element abundance variations (known as multiple populations, MPs). Such chemical anomalies have been found in (nearly) all the ancient GCs (more than 10 Gyr old) of our Galaxy and its close companions, but so far no model for the origin of MPs is able to reproduce a…
Cluster mass calibration at high redshift: HST weak lensing analysis of 13 distant galaxy clusters from the South Pole Telescope Sunyaev-Zel'dovich Survey
Simon, P.; Schrabback, T.; Foley, R. J. +26 more
We present an HST/Advanced Camera for Surveys (ACS) weak gravitational lensing analysis of 13 massive high-redshift (zmedian = 0.88) galaxy clusters discovered in the South Pole Telescope (SPT) Sunyaev-Zel'dovich Survey. This study is part of a larger campaign that aims to robustly calibrate mass-observable scaling relations over a wide…
Snake in the Clouds: a new nearby dwarf galaxy in the Magellanic bridge*
Casey, Andrew R.; Erkal, Denis; Belokurov, Vasily +9 more
We report the discovery of a nearby dwarf galaxy in the constellation of Hydrus, between the Large (LMC) and the Small Magellanic Clouds (SMC). Hydrus 1 is a mildly elliptical ultrafaint system with luminosity MV ∼ -4.7 and size 53 ± 3 pc, located 28 kpc from the Sun and 24 kpc from the LMC. From spectroscopy of ∼30 member stars, we mea…
Halo substructure in the SDSS-Gaia catalogue: streams and clumps
Myeong, G. C.; Evans, N. W.; Belokurov, V. +2 more
We use the Sloan Digital Sky Survey (SDSS)-Gaia Catalogue to identify six new pieces of halo substructure. SDSS-Gaia is an astrometric catalogue that exploits SDSS data release 9 to provide first epoch photometry for objects in the Gaia source catalogue. We use a version of the catalogue containing 245 316 stars with all phase-space coordinates wi…
Intracluster light at the Frontier - II. The Frontier Fields Clusters
Trujillo, Ignacio; Montes, Mireia
Multiwavelength deep observations are a key tool to understand the origin of the diffuse light in clusters of galaxies: the intracluster light (ICL). For this reason, we take advantage of the Hubble Frontier Fields (HFF) survey to investigate the properties of the stellar populations of the ICL of its six massive intermediate redshift (0.3 < z …
Metal-enriched galactic outflows shape the mass-metallicity relationship
Chisholm, J.; Leitherer, C.; Tremonti, C.
The gas-phase metallicity of low-mass galaxies increases with increasing stellar mass (M*) and is nearly constant for high-mass galaxies. Theory suggests that this tight mass-metallicity relationship is shaped by galactic outflows removing metal-enriched gas from galaxies. Here, we observationally model the outflow metallicities of the …
Multiple stellar populations in Magellanic Cloud clusters - VI. A survey of multiple sequences and Be stars in young clusters
Di Criscienzo, M.; Anderson, J.; Milone, A. P. +16 more
The split main sequences (MSs) and extended MS turnoffs (eMSTOs) detected in a few young clusters have demonstrated that these stellar systems host multiple populations differing in a number of properties such as rotation and, possibly, age. We analyse Hubble Space Telescope photometry for 13 clusters with ages between ∼40 and ∼1000 Myr and of dif…